I managed to injure my left leg when I was wrestling around with those massive batteries for the solar power system so my physical activity was seriously limited for a couple of weeks. Yesterday was the first day I felt comfortable enough to get out on the bike for an extended ride, and it was a great day to start. Was absolutely beautiful out with temps in the high 70s and a gentle breeze.
I injured my left calf pretty seriously back in the 1990s in a farm accident. Took me 6 weeks to recover from that one and ever since I’ve had to be cautious with that leg. Lugging 100 lb batteries down the basement stairs and into the battery cabinet didn’t do the leg any good. Neither did repeatedly kneeling down on the floor to work on wiring.
Out in the gardens the irises are coming into full bloom. They don’t bloom for very long but when they do that whole area is covered with these amazing flowers in brilliant blue, purple and yellow. When the sun hits them the colors are so brilliant they almost glow.
More solar stuff: I really need to do some meaningful testing of the EG4 system to get some basic data about run times and things like that. I can guess how long the batteries will last when running the house off the EG4 system but I don’t have any actual operational data giving me actual run times under particular sets of circumstances and things like that. Two days ago I started it up, took the house off-grid and ran entirely from the EG4 system starting at 7 AM and ending at 3 PM, a total of 8 hours. At the end of that time the batteries were still at about 78% capacity because we had a pretty good day for solar production. While that was interesting I really need to see how long I can run the house just off the batteries, with no solar power at all.
The string of Newpowa panels have been peaking at around 1,000 watts, and the HQST panels at around 600 watts. That’s less their rated peak output which should be around 1,320 and 800 respectively. The HQST panels were putting out close to 700W earlier this year so I know they can do better than what I’m seeing. And the weather was clear with bright sunshine…
Or was it? The sky looked clear when looking straight up, but if you’d look towards the horizon it was a different story. The wind shifted again and we’re back to getting air quality alerts because of the forest fires in Canada. It looks clear and sunny but it really isn’t. There is a significant amount of fine particulate material floating around in the atmosphere that is cutting back on the amount of solar radiation that is reaching the ground. What it boils down to is that I theoretically have enough solar out there to take my batteries from about 50% to near 100% in one day of full sun. In reality, with variable cloud conditions and the smoke from the fires, I’m lucky if I get half of that.
(And I can sure tell there are air quality problems with my allergies, too. I was up at 3 AM this morning with my head so stuffed up I could hardly breathe. I gave up trying to get back to sleep. Since all of this air quality stuff started I’ve been having problems sleeping, stuffed up sinuses, etc. Makes it very hard for me to stay asleep. I’ve generally been waking up around 3 or 4 AM and find it almost impossible to get back to sleep again. Running on four or five hours of sleep is unpleasant. Sigh…)
Speaking of battery charging I got one of these in earlier this week from Signature Solar, the EG4 Chargeverter, a 48V battery charger that plugs into a 240V AC power source to rapidly recharge LiFePo batteries. This thing can put out up to 100 Amps which means it could fully recharge my 15 KWh of batteries in just 3 hours. It’s only been on the market for a few months and I’m curious to see how well it works so when I get a chance to check it out I’ll talk about it in the future.
Now why would someone need one of these? After all a lot of modern inverters like my EG4 6500EX already have built in AC battery chargers. I could wire my EG4s directly to the house’s AC power and they would automatically keep the batteries topped up even when there is no solar. But a lot of these systems are sold to people who are entirely off the grid. They have no connection to the grid at all. (And my system has no grid connection.) If they don’t get enough solar power to keep their batteries topped up, they have to resort to using a gasoline powered generator to charge them up. And that’s where the problems come in. These cheap, gasoline generators often produce very dirty power that isn’t even close to a pure sine wave and which can damage electronics. This chargeverter apparently doesn’t care how dirty the AC power coming into it may be. So if you’re living entirely off the grid, or if you’re going through an extended blackout and there isn’t enough solar to keep the batteries charged, you could plug this thing into a cheap Harbor Freight generator to charge your batteries and not have to worry about damaging anything.
I have a 7,500W Generac gasoline generator sitting out in the garage and this thing should plug right into it so I’ll be testing this out in the near future. If it works as advertised it will probably be kept permanently wired up to the bus bars in the battery cabinet. I doubt if it will get much use but it could come in very handy if we have an extended power outage.
What I’ll probably do is run my batteries down to about 25% and then try charging them with the chargeverter connected to the Generac and see what happens.
Now that I’ve been actually using the solar power system for a few days I’ve run into a few interesting quirks. First the solar charging system. Other people with the EG4 6500EX inverter, or who are thinking of buying one, have been following along so I thought I’d warn you about this.
Up in that photo are 5 new 220W solar panels from Newpowa. I picked up 6 of those because I badly need more solar but I don’t have a lot of space to put them. These from Newpowa were the smallest size 200W panels I could find and that’s why I bought ’em. The charger in the EG4 is rated between 80V to 500V input from solar. That’s the minimum amount of voltage it takes to “trigger” so to speak the charger, and the maximum voltage it can handle from the solar panels.
Those five panels in series were putting out about 91 volts, which should have been enough to make the charger work properly. But apparently not. When I plugged them into the EG4 it looked like I was only getting about 450 – 500 watts out of panels that should have been putting out at least 75% – 90% of their rated capacity under the conditions I had that day. They were putting out half of what they should have.
I went back out, checked all of the connectors, all of the wires, made sure I had everything wired properly and couldn’t find any problems. The EG4 has two solar chargers so I plugged into the second one. Nope, same thing, I was only getting a little over 500W under full sun.
Grr, so now what… Could it be that 91V wasn’t enough? I had one more panel that I didn’t have room for. I shuffled things around and connected up all six panels and then checked. I was now getting a bit over 100V and…920W? Yeah, 920 watts. Adding that one panel, kicking the voltage up another 10V doubled the amount of power the panels were putting out.
So apparently that 80V lower limit on the solar charger in the EG4 isn’t quite accurate. I had to push 100V into it in order to get the charge controller to get it to work properly. So if you have one of these things and you aren’t getting the wattage out of your solar panels you think you should, check your voltage. If your panels are putting out less than 100V that could be it.
The other oddity is also related to solar charging. Before I configured the two inverters to work in parallel I was using one inverter alone for testing. It exhibits some interesting behavior. If I had the inverter physically turned off with the switch on the front panel and plugged solar power into it, it would turn itself on and start charging the batteries.
I personally find this a bit troubling. If I have a device that is physically turned off, I expect it to remain off. Period. Now I can understand why they might do this. If you’ve been using the system from battery only and drain the batteries down and shut the system off, it might then start to recharge the batteries automatically when it begins to get solar power. It turned on only the solar charger, not the inverter, so it wasn’t putting out AC so that was something at least.
Once I put the two units in parallel, that behavior changed. When I plugged solar into the turned off master inverter, it would still turn itself on with the power switch turned off. But it wouldn’t actually charge the batteries. It looked like it was in charging mode but it really wasn’t. It indicated it was getting only 47W of power out of solar panels that were putting out 500W. Eventually I figured out that both units need to be physically turned on with the power switch before it will now start actually charging the batteries. I find that disappointing as well. I’d prefer to be able to do what I did before, which was to use the unit to charge the batteries without having to switch the inverters on. Running an inverter while it’s just “idling” along without drawing power from it uses a small but still significant amount of power from the system. Each inverter takes somewhere between 70 – 90 watts of power, or 140W – 180W for the pair. And that’s 140+ watts that could be going into the batteries.
One last observation. These things aren’t exactly quiet. The fans on the EG4s run all the time the units are operating, and depending on the load on the units those fans quickly ramp up in speed. Tucked away in the basement this isn’t a problem but if you’re putting them near a living space some people could find the fans more than a little annoying.
One last thing about the solar system. I finally got the batteries mounted in the cabinet. And found that my existing battery cables going from the inverters to the batteries are too short because of course they are. So it’s time to get out the crimping tools and spend even more money on overpriced copper cable. Always something…
We moved the two raised beds from the north side of the backyard to the south side. In the previous location they were starting to get shaded out by a fast growing maple tree and a spruce tree. Growing conditions there were getting worse every year. Now that the ash tree is gone the area where we moved them now gets full sun all day long. Moving them was simple but took a lot of physical labor. Had to shovel out all of the dirt in them, drag them over to the new location and then shovel all the dirt back into them.
We’re doing some decorative work as well. An old, crumbling stone wall is being pulled out along the west side of the garage and being replaced with block, so we got a pallet full of blocks coming in the near future.
I’m not looking forward to that project. I am, at heart, a lazy person when it comes right down to it. I’ve developed an allergy to hard physical labor over the last few years. Still, it needs to get done.
Let’s see, what else? Oh, I found this while I was biking around the other day and I had to stop and take a picture of it.
We have some interesting people around here, including some who are pretty good folk artists. From the road I thought this was a real person for a brief moment when I saw the hi-viz vest.
And let’s finish up with a cat.
We had to take care of our youngest son’s cat for a few days while he was on vacation and she, being a cat, decided she owned the house.
Yeah, that title is probably a lie. I’ll probably talk more about it in the future as I gain experience with this. I’ll certainly let you know if I run into problems. And you’re probably getting tired of reading about as I am of writing about it so let me wrap this all up.
The good news is that the damned thing actually works. I got tired of waiting for some miscellaneous parts to arrive to do the final installation and cobbled together a messy looking but safe wiring configuration so I could get on with testing the inverters. That may look like a mess down there, but it is, frankly, a lot better looking than some of the wiring I’ve seen people turn out on Youtube and other places.
But it is a mess that works and, believe it or not, is safe. And the battery cabinet is here now so today this whole thing is going to get torn down and put back together the right way and will meet building codes, etc.
I fired the sucker up. I went through the “commissioning” procedures in the manuals to set the two inverters up to run in 240V split phase, rebooted everything and it all started up and, well, damn. It actually worked! I had the entire house was running off-grid, running from the inverters, batteries and solar panels. Everything in the house was working just as it did running off the grid. Lights, microwave, coffee maker, even the 240V appliances like the stove and clothes dryer. Just for the heck of it I fired up my big table saw in the wood shop. The lights flickered a bit when it first kicked in, but they do that even when I’m running off grid power. End result is I ran the house for the rest of the afternoon off the two inverters with no problems at all before shutting it down and pulling the plug, so to speak, so I could start prepping to put in the battery cabinet.
So, it works! I actually put together something that works? Wow…
So for those of you who are interested in all the technical stuff and some observations about the equipment, let me get on with us. Some of this I’ve mentioned before but I want to make sure I covered everything for those of you who are interested in putting together a solar power system yourselves. And yes, I’m going to include the actual retail cost of all of this as well along the way. So so be warned this could get long.
So let’s start with the inverters.
What I have are two EG4 6500EX all in one inverters. Each one can handle a sustained load of 6,500 watts with a surge capacity of 13,000W for up to 5 seconds. When some equipment (like my table saw or sump pumps) first start up they can demand huge amounts of power for a brief time, so that’s why that surge capacity is important. Both of them together give me 13KW load capacity, more than enough to run the entire house.
Each inverter has two MPPT solar charge controllers. Each of the two chargers can handle up to 4,000 watts of solar panels at 80 to 500 volts. And I can tell you that they absolutely have to have at least that 80V before they’ll start charging the batteries. Anyway that’s some pretty hefty solar charging capacity. If I’d max out the capacity of both inverters I could feed about 16KW of solar power into these things.
If the inverter is connected to grid power it can charge the batteries off the grid, or off solar, or off both, or prioritize one source over another. And I’m told these things, if hooked to the grid, will pass through grid power to your house, and switch to battery/solar power in case of a blackout, and do it in 10 ms. I don’t have mine hooked to the grid and don’t plan to so I’m not going to be able to test that.
The battery chargers, both solar powered and grid powered, can be configured to deal with just about any kind of 48V battery system you might have, ranging from old fashioned lead acid batteries up to state of the art LiFePo batteries like the EG4LLs I have. You can set maximum and minimum voltages, rate of charge, you name it. In my case I just told it I was using EG4LL batteries and it automatically sets itself up properly. It also has battery communications as well to talk to the battery management systems most LiFePo batteries have these days. And I should add that the inverters are UL listed as well so they should be able to pass inspection.
And, of course, two of these units can be paralleled together so that when combined they work as a single 240V split phase system, which is how I have mine configured at the moment. One inverter is set as the master and the other as the slave, and a setting in the menu has to be changed to make sure that the slave’s sine wave is 180 degrees out of phase with the other inverter. That took maybe all of a minute to configure.
And if the 13KW that two of these together make isn’t enough for you, you can connect up to six of the things if you need more power.
There are lots more options and settings and other things that I’m not going to get into because it would take forever and I don’t really care about a lot of them. If you’re interested in all of that you can download the manual from Signature Solar.
So, let’s talk cost. Personally I think that considering the capacity of these inverters and the things they can do they’re pretty inexpensive, $1,299 each. Since I wanted 240V I needed two of them. Signature Solar had a combo deal that included two EG 6500EX inverters, two PV cutoff switches, two battery disconnect switches (which you need to meet code) and some cables and a few other goodies for a bit less than $3,000, so that’s what I ended up buying.
I am not urging you to buy EG4 equipment by any means. These are just the ones I ended up getting because they suited my needs. There are a lot of different inverters on the market and most of them work pretty well. Some are better than others. But as you go shopping around you will find that a lot of different brands seem to have remarkably similar specifications, and even seem to look quite a bit alike except for the case. That’s because they are basically the same inverter, just packaged differently. I know of at least two other inverters, sold under different brand names, that are exactly the same as the EG4 6500 that I have. There are some minor differences, like the EG4 can handle higher PV voltages, but other than that they’re identical except for the case and graphics and they all come out of the same factories in Taiwan and Singapore.
Batteries are the most expensive part of a system like this. 48V LiFePo batteries are expensive. But when the sheer energy storage capacity of these things is taken into consideration, along with their life span, they actually are very cost effective.
What I ended up getting were EG4LL, 48V, 5,120 Wh capacity server rack style LiFePo batteries. These are “smart” batteries with built in battery management systems and both RS485 and CAN communications capability and fancy full color LCD screens. They have a 10 year warranty and it’s claimed that after 7,000 charge/discharge cycles they’ll still have 80% of their original capacity left.
A word about battery safety. You’ve probably heard all kinds of stories about lithium batteries exploding, starting unquenchable fires and all of that. These are not those types of batteries. These are lithium iron phosphate, LiFePo, and they use a different chemistry. They do not explode, do not turn into raging infernos, etc. And just for the extra paranoid people out there (like me), these particular model batteries have their own fire suppression systems built in. I saw a demonstration where they took one of these batteries, piled a bunch of flammable material on it and started the sucker on fire. After burning for a few minutes, the suppression system triggered and the battery put the fire out. Cool, I said. I’ll take those, please.
The LCD screens let you monitor all kinds of stuff that I’m sure will interest someone. The only thing I really care about is if they work or not, and they do. But if there are problems you can even monitor the state of health of individual cells in the battery if you need to. If you want to save a few bucks EG4 also sells batteries that have the same capacity as these, but without the fancy displays.
The batteries have communications ports which allows them to be connected to the EG4 inverter which directly monitors the battery conditions so it doesn’t over charge them, charge them too fast, discharge the too fast, etc. If you have more than one, one battery is set up as the “master” which connects to the inverter, and the other batteries comm ports are daisy chained to the master battery. There are DIP switches on the front of each battery that you need to set so the communications system can figure out which one is which. Don’t worry, it’s easy. The batteries come with a booklet that has a chart showing exactly how to set the switches.
The batteries come with short (very short) battery cables designed to to connect them to the busbars in a battery cabinet. If you aren’t going to use a battery cabinet you’re going to have to buy or make your own cables to connect them to your own busbars. If you need to go down that route you need to remember that the cables connecting multiple batteries to a busbar need to be the same length and gauge. If the cables aren’t matched in length and gauge it means they aren’t going to have the same resistance. You want the load on each individual battery to be as evenly distributed as possible. That’s why you need to use busbars rather than just daisy chaining the batteries together. It helps to distribute the load more evenly.
And if you’re going to make your own, go get yourself a decent hydraulic crimping tool! I do not recommend one of those cheap crimpers that you whack with a big hammer. I don’t trust those things. You risk damaging the cable, damaging the lug, and not making a very good connection inside of the lug. A decent hydraulic crimper will set you back about $100 or so, which seems like a lot. but if you’re making cables for a power system that’s costing $10,000 or more, do you really want to cheap out on a crimping tool and risk making bad connections?
If you haven’t had to buy heavy gauge copper wire recently you’re in for a shock. Two 10 foot pieces of 4 gauge copper battery cable costs about $170 off Amazon. And while it is very nice cable and it comes with a bag of copper connecting lugs that’s still a heck of a lot of money. That’s another reason to go with a battery rack like the one I got. That big steel box may cost $500 but making or buying cables to hook the individual batteries to a wall mounted busbar is going to cost you several hundred dollars by itself.
The EG4LL batteries sell for $1,750 each. I have three of then for a total cost of $5,250. You can save a few bucks by going with batteries that don’t have all of the bells and whistles that these do,. The cheapest 48V server rack style LiFepo batteries that I’ve seen for sale are are around $1,500, so you could save yourself about $250 per battery by doing some shopping around.
So the running total right now for the system is about $3,000 for the inverters and $5,250 for the batteries, a total of $8,250.
But we’re not done yet.
To put together a system like this a lot of other misc. parts are needed, and perhaps also some specialty tools like that crimper I talked about. I strongly recommend you get a decent torque wrench to make sure all of those electrical connections are torqued to the proper specifications. You don’t want to end up having to ship an inverter or battery back to the manufacturer, at your cost, because you snapped off a bolt or stripped out the threads on a connector trying to hook something up.
You also need some test equipment like a decent voltmeter and an amp meter. If you don’t already have all of that, you need to add that cost into the total price. Test equipment isn’t expensive and if you’re fiddling around with electrical equipment you need to have it anyway.
Let’s talk battery cabinet. The one in that photo came from Signature Solar and cost me about $500. It’s big enough to hold 6 batteries, has the busbars to connect to the batteries already installed, and it’s built like a freaking tank. It’s made of heavy gauge steel with a locking door, and has heavy duty wheels that can handle the weight because it can hold something like a quarter of a ton of batteries. And as I said it can save you enough money in cables to pay for itself.
Feel free to make your own if you’re handy that way. Just make sure it has adequate ventilation (batteries do get warm under normal operation) and that it can be secured somehow to keep people from fiddling around with it.
There are some safety items you absolutely are going to need. First you need battery cutoff switches between the inverters and the batteries so you can kill power to the inverters quickly in case of an emergency. Look at the photo up there. The two small gray boxes under the first inverter are first a PV cutoff switch and to the right of that the battery cutoff/circuit breaker. I only just got those mounted when I took the photo so they aren’t hooked up yet. The batteries have their own circuit breakers and I have a PV cutoff already in the system that you can’t see in this photo so I don’t have these hooked up yet. The final wiring job will have a PV switch and battery breaker for both inverters.
A decent PV cutoff switch is about $90. The breaker is about $70. I got two of each in the package deal I bought from signature solar. Total cost about $320 if you have to buy them separately.
Oh, and did I mention your solar panels need to be grounded? Yeah, they do. Almost all solar panels, at least the ones I’ve seen, will already have holes, often marked with a special grounding symbol, on the frames. Generally you daisy chain a grounding wire to every panel, then that wire goes to a grounding rod near the panels.
I should add that I already had a lot of the stuff I needed like spare wire, connectors, conduit, etc. laying around because I’m an amateur radio person and I’m constantly tinkering with antennas and fun stuff like that so I already had ground wire, grounding rods and other misc. bits on the shelf.
Now we come to the house side of things. You somehow need to get the power produced by those inverters into your house’s electrical system.
First you need to run suitably sized wiring from the inverters to your service panel. The EG4 manual recommends 6 gauge wire which is going to be sufficient to carry the amperage the inverters can produce. In my case I used 6/2 (6 gauge wire, 1 hot, one neutral, and one ground). That stuff ain’t cheap either. It runs about $3.50 per foot here. That’s why ideally your inverters will be reasonably close to your service panel. Depending on regulations in your area that cable may need to be run through conduit. Even the relatively short run I had to make ended up costing me close to $300 in wire for that, not including the cost of the conduit.
Now I am going to give the usual disclaimer here about using a licensed electrician to make any modifications necessary to the service panel that feeds electricity to your house. In a lot of jurisdictions it may even be illegal for you to make any modifications to your house’s electrical service.
It’s Money Time
So here’s the total cost of this whole house off grid (sort of) alternative energy system, not including solar panels. This number includes the two inverters, three batteries, all of the cables, connectors, switches, electrical wiring, etc. It includes the crimping tool, a cable cutter, torque wrench, wiring to the house panel, circuit breakers, screws, bolts, etc. Prices are rounded. It does not include the cost of Bob the electrician who makes sure I don’t blow things up and keeps the inspectors happy.
Inverter combo deal including 2 EG4 6500EX inverters, two battery breaker boxes, 2 PV disconnect switches and some misc. bits and pieces: $3,000.
Three EG4LL 48V server rack style batteries at $1,750 each: $5,250
Battery cabinet: $500
Equipment total from Signature Solar: $8750.
Wait, we’re not quite done yet.
Now we need to add in the misc. costs for wire, cables, connectors, a few speciality tools I had to buy. I won’t itemize all of that. That all added up to about $2,500 rounded to the nearest hundred bucks. Wire is crazy expensive right now, a transfer switch that is eventually going to be hooked into the system set me back almost $500, some circuit breakers for the electrical panel, conduit, fittings. Oh, and lunch for Bob is in there somewhere too I think.
Grand total, not including solar panels: $11,950.
My original cost estimates for this project, minus solar panels, was around $12K to $13K so estimates were spot on.
Now let’s talk solar panels. Solar panel prices are currently sitting at a bit more than $1 to $1.50 per watt. And a system this size is going to need a lot of watts to charge the batteries in a reasonable amount of time even without trying to run your house off solar as well. It’s going to take quite a bit of solar power to keep this system fed. There are 15 KWh of batteries to keep charged plus one would want to get as much solar power as possible to feed through the inverters directly into the house to use solar power directly, not just charge batteries.
I only have my original 800W of solar out there right now, but I just got in 1,320W of solar panels last week and if the budget permits I’ll be adding another 1,320W by the end of June and I’ll have more than 3KW of solar sitting out there.
To make a long story a bit shorter, total cost for this whole project, including solar panels, is going to be right around $15K
Now let’s talk about taxes. There is a federal tax credit for up to 30% of the cost of alternative energy projects, including solar. I’m not exactly sure of all of the details because that’s what I pay my accountant for (Hi, Eric, how you doing? Recover from tax season yet?) Theoretically I could get up to $4,500 in federal tax credits. I doubt if I will. Considering what the tax system is like in the US I’ll be surprised if I get anything at all. But let’s say I do. That would bring the cost of this down to $10,500. Ooo, nice. Personally I think that getting a solar power system that can run my entire house for ten grand sounds like a pretty good deal.
Is it really worth it though? Even if I get the tax breaks that is a hell of a lot of money and a hell of a lot of work. I talked about pay back times and other factors involved before so I won’t go into that here. All I can say at this point is that only time will tell. If nothing else we’ll have a whole house emergency power system we can fall back on during a blackout even if we don’t save a lot of money on the utility bill.
Oh, and I just heard that all of the electric utilities in the state are pushing for yet another rate increase of anywhere from 4% to 8%. So there’s that. And I have friends in the electric utility industry and from what I hear from them we could be looking at wide spread rolling blackouts if we get above average temperatures, so there’s that too… Hmm, maybe this was a good idea after all.
A few things struck me as we were proceeding with this project.
First is the cost. $15K is a lot of money but if you think about for a moment, is it really all that much? We’re talking about a system that can handle all of the electrical needs of an entire modern household, at least part of the time, for less than the cost of a decent used car. If you can snag the 30% tax credit it makes it look even more attractive.
Second thing that struck me was how ridiculously easy it was to put this system in. If I’d had all of the parts and bits I needed right off the bat I could have installed this whole system in an afternoon and still have had time to go play with the neighbor’s dog before supper. The inverters have become so sophisticated these days that it’s almost a plug-n-play system. You don’t need separate solar charge controllers, separate AC battery chargers, separate battery management systems, etc. Everything is built right in. If you can read a manual, are qualified to do basic electrical wiring, have some basic tools and test equipment, etc. just about any reasonably intelligent person can set this up. Of course there are a lot of, if you’ll excuse the term, idiots out there. Some of them are on Youtube. Start scrounging around on Youtube sometime searching for solar power systems and you’ll see what I mean. And that’s why cities, towns and counties have to have building codes and inspectors and permitting processes.
The third thing that struck me was that I’ve been going on and on and on about this system for this long when I should be going on and on and on and on about biking, nature, photography, gardening, amateur radio and the other stuff I normally bore you with.
So that’s it. It’s time to get back to our regularly scheduled programming. I’ll keep you up to date about the system but unless something major happens it will be more of a sidenote than anything else while I get back to the more important things in life, like screwing around out in the gardens, bothering people on amateur radio, etc.
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So, on Monday, May 1, this is what it looked like outside my front door at 5 AM.
Yes, that’s snow. Nice weather we get here. This is why I haven’t been talking about gardening and bicycling and drone flying and putting up photos of pretty flowers and all that stuff. We had two or three days of summer like weather in March with temperatures in the 80s, and ever since then it’s been like this… cold, wet, cloudly, and now snow. Welcome to Wisconsin. Sigh… The weather has since gotten a bit better. It’s still been so cloudy with occasional rain that we’ve been making pretty much zero solar power. Again, sigh… Of course I shouldn’t complain. I have a friend who lives about 100 miles north of here in the upper peninsula of Michigan and over last week or so he got 52 inches of snow.
What I wanted to talk about is that someone asked why I need two inverters bolted to the wall and not just one. Just one of those inverters can supply 6.5 KW of power, as much as my big Generac gasoline generator, and enough to run almost the entire house as long as we’re careful. So why do I need two of them?
Partly it’s a question of capacity. 6.5 KW is a bit close to the edge for us, so to speak, at least as far as normal daily life is concerned. We may complain about our electric bill but we do like appliances like our coffee makers, our convection oven, etc. With just one inverter there would be times we would be pushing over that 6.5 KW limit. Two inverters give us a comfortable cushion.
The biggest reason though is that we also need 240V power to run some of the appliances in the house. For that we need both inverters. Initially I’m not going to be hooking any 240 appliances into this system because I don’t have eno0ugh batteries and solar panels to handle it, but eventually that’s going to change so I wanted a system that could be switched over easily in the future.
WTF is 240V split phase?
The average person doesn’t know, and doesn’t need to know, what actually goes on in the electrical system of the house. As long as your toaster or computer or TV works when it’s plugged into the wall and the lights turn on when the switch is flipped, that’s all they care about. And for most people that’s fine. But if you want to switch your home to an alternative energy system you need to know what’s going on behind the scenes.
While most of the systems in your house run on 120 VAC, in all likelihood there are some that require more power than a normal 120V line can supply. Things like electric water heaters, clothes dryers, electric stoves, well pumps, etc. will often run on 240V, not 120. The amount of power these appliances require would overload the normal 120V wiring systems in the house. So let me explain what’s going on without this getting complicated.
Well it’s going to get complicated anyway but let’s see what I can do.
What you have coming into your house is two, 120V AC power lines, not one. The two lines can be combined inside your circuit breaker panel to give you 240V to power more power hungry appliances like HVAC systems and clothes dryers.
If you took the front panel off of the main circuit breaker panel in your house it would looks something like the one in the photo below.
Now you’ll notice a couple of things right away if you look at that photo up there carefully. Note that there are two rows of circuit breakers, not one. There is a reason for that and I’ll come to that in a minute.
The next thing I want you to look at is right at the top center of that picture. You’ll see three thick wires coming in from the top. One is black, the 2nd is marked with red tape, and the third runs off to the right of center and is marked with white. Those three lines are what comes in from the service panel attached to the outside of your house and which, in turn, is fed from the utility company. The black wire and the red are the two 120V lines coming into the house and the white is the neutral line.
In your panel are two metal strips called busbars that the two hot wires (sometimes called legs because why not) connect to. Each busbar runs the length of the panel. The circuit breakers in the panel connect to those busbars to get the power that they then send out to the wires that lead to the outlets, lights, etc. in your house.
The circuit breakers on the left side of the panel get their power from L1, and the ones on the right get their power from L2.. Each busbar provides 120V.
So how do you get the 240V? Look at the top of the right row of breakers and you’ll see what looks like two breakers that are joined into one by a bar that connects the two switches together. That’s a 240V breaker.
Well, sort of. It doesn’t actually give you 240V. What it does is tap into both of the busbars at the same times, and lets you run two, 120V hot wires to whatever device that breaker breaker powers. The appliance that circuit energizes can combine both to provide 240V or use the individual 120V lines to power individual circuits in the appliance.
So if you want to design an alternative power system to run your whole house through your existing electrical system, you need a system that provides 120V to both L1 and L2, a 240 split phase system as they call it. And no, I can’t just feed 120V from a single source into both busbars at the same time because L1 and L2 are 180 degrees out of phase with one another and that is important. Or so they tell me.
Okay, so what’s with this phase stuff? Well it gets even more complicated and there is a hell of a lot of misinformation out there about what’s generally called “240V split phase”. There are people out there who will try to tell you that you need 240V split phase to power two phase motors, only there really aren’t any two phase motors out there and there haven’t been in many, many years. Or they’ll tell you you need split phase for electronics which is total BS because almost all modern electronics run off DC not AC…
Okay, look, the reason you have split phase coming into your home… Oh, hell, let’s look at what they’re talking about first of all.
AC stands for alternating current, and it’s called that because it, well, alternates. It doesn’t provide a steady positive voltage the way DC does. It alternates from plus to minus at 60 cycles per second. If you were to hook an oscilloscope up to an AC power line what you’d see on the screen is something like what you see in the picture over there on the left.
If you could look at both L1 and L2 at the same time on an oscilloscope it would look something like the picture over there on the right. The two are 180 degrees out of phase.
Why do we even use this system? It would take me pages and pages to explain all of that so I’ll leave it to you to go scurry over to Wikipedia or somewhere and find out for yourself.
So you have two, 120V lines coming in your house and they are 180 degrees out of phase with one another. Sort of. Kinda. And that’s important for, well, reasons, all right? And the two lines can be combined to give you 240V to power bigger appliances. Or not.
Are you confused yet? I am.
But let’s get back to my setup here. Each of the inverters will supply 1 of the two hot lines needed to get 240. And the two inverters “talk” to each other over a communications line so their sine waves are 180 degrees out of phase when in the split phase mode. Which is important for, well, for reasons. Or so they tell me. That’s what we’re stuck with.
But at the moment I don’t want to run any of my 240V appliances off this system. First of all that equipment sucks up huge amounts of power which would drain my batteries fast. The second issue is that my central air conditioning system quite possibly would require more amperage than my batteries can supply. EG4 recommends having at least 5 batteries in order to supply enough amperage to start up a big HVAC system like mine and I only have 3 at the moment.
To make a long story a bit shorter, I have two inverters because I’ll probably almost certainly need a system that can provide more load capacity than a single inverter would give me, and I eventually may want to expand the system to get 240V if I ever get enough batteries and solar panels up to support it.
But I’ve bored you long enough with this. let’s get on with it…
One of the things I ordered for this system was a battery cabinet to hold the batteries that has its own built in busbar system for connecting the batteries, and which is also lockable to keep people from fiddling with things they shouldn’t. That was on backorder and I got an email from Signature Solar telling me I could either wait, or they could ship me a slightly different model cabinet. Like everyone else they’re still having supply chain issues. I told them I’d take the different model and that should be here Monday. I jury rigged things together so I could test the inverters and charge the batteries but it can’t stay that way. Once the cabinet arrives I can get the batteries properly configured and start putting everything together.
I have more solar panels on order because my 800 watts of solar is woefully inadequate to keep 15 KWh of batteries charged. Those are supposed to be coming May 15 so I’ll need to build frames to hold all of those.
The weather hasn’t been very good but we’ve managed to get some work done out in the gardens. Once things warm up and the skies clear up we’re going to be really busy. We’re taking out a crumbling stone wall and replacing that, moving two of the raised beds to a new location and a bunch of other stuff going out there. MrsGF has had her indoor greenhouse going down in the basement for weeks already starting plants that will get transplanted outdoors as soon as the weather permits.
The brewery called me the other day, asking if I’d make more drinks coasters for them. A couple of good friends opened a brewpub, something they’d dreamed of doing for years. So they bought a building with an existing tavern that had enough room for them to put in their brewery and then… Then Covid hit. And somehow they still managed to pull it off and even managed to pay the bills during that whole mess. And now they’re doing pretty well.
Anyway a while back I found some super cheap plain drinks coasters made from wood and some from paperboard and for the heck of it I fired up Photoshop and made some graphics, putting their logo on one side and an allegedly humorous illustration on the other and then used the laser engraver to burn it into the coasters. i thought they looked a bit on the unprofessional side but they were fun to do so I did a few. I never thought they’d actually use them in the bar. But they did, and apparently the customers loved them. And stole them. Which was okay because it’s good PR for the brewery. So I’ve done dozens, maybe a couple of hundred of these things over the last couple of years and I just got a request for more so I got that going on. People are easily amused, I guess.
But enough of this. I need to get going here. I’ve probably put you to sleep already with all of this. I know I’ve nodded off a couple of times myself…
It’s here! This pallet with 500 lbs. of equipment was delivered from Texas Wednesday last week.
And not only is that pallet full of stuff heavy, it’s expensive, and that’s what I want to talk about today, money.
What I have on that pallet are two, 6500W inverters with built in solar charging systems, three 5 KWh LiFePo batteries, and some misc. parts and cables to make it all work. That pallet up there cost me right around $9,000. And by the time I add in the cost of cables, connectors, bus bars, circuit breakers, the parts I’ll need to connect it all to the house’s electrical systems and a few specialty tools I need, I’ll have about $11,000 invested in this. And then I still need to add more solar panels. Let’s call it a total of about $13,000 for the entire system.
That’s a hell of a lot of money. Or is it, really? Think about it for a moment. When fully configured this system is going to be a complete 13 KW, 240V split phase power generating system that can provide enough power to run the entire house, entirely off grid if I can get enough solar. And if we’re conservative with our electrical usage at night, enough battery capacity to carry us through the night until the sun comes out again. Once you consider that, that $13K price tag begins to seem a bit less shocking.
This system should also qualify for the federal energy tax credit, which means I could get back about 30% of the cost in tax credits. If my accountant can pull that off that would bring my out of pocket cost down to under $10K. But to be honest I’m not counting on that money. The US tax system being as convoluted and laden with pitfalls and booby traps and the like, I am not counting on that money and will be pleasantly surprised if we get it.
So the question now is will this system eventually pay for itself? The answer depends on equations that have a lot of “ifs” in them.
When we ran the numbers on all of this we knew right up front that while this system could handle all of the house’s power requirements, we’re never going to actually achieve that. There is no way that we could put in a system that would take us entirely off the grid. This is, after all, Wisconsin. We get a lot of days up here where we will be generating no solar power at all because of the weather. We can go for a week or more without seeing the sun. So we assumed that, at best, this system might be able to handle half of our electrical usage when averaged out over the course of the year. That is optimistic. I admit that, but it’s a place to start anyway.
Our electric bill right now is averaging around $300/month, $3,600 a year. Half of that is $1,800. We have $13K invested in this system. 13,000 divided by 1,800 is 7.2. So the equipment would pay for itself in about 7 years. That’s really not too bad, all things considered.
If we get the tax credit things look even better. That would bring the cost down to under $10K or so. That would bring the payback time down to about five and a half years.
But as I said, there are a lot of “ifs” in that equation. If the weather cooperates, if the equipment works as specified, if the batteries hold up that long, if we don’t have any significant problems with the system, if we can get enough solar panels up to feed it, if… You get the idea.
If you’re thinking of putting in a system like this yourself, here is another thing to consider. The only reason this system is coming in at this price is because I’m doing almost all of the work myself. I got some estimates on similarly sized systems from contractors and the numbers were a bit eye watering, to say the least. If put in by a professional installer I’d have been looking at prices anywhere from two to four times as much as this. That’s right, prices ranging from about $27,000 to well over $40,000.
Now let’s talk about another aspect some people think about, which is using a system like this to sell power back to the utility company. You’ll hear claims from people that you can make a system like this pay for itself by selling power back to the utility.
Let’s get one thing straight right up front. Utility companies are a government sanctioned monopoly that exists for one reason, to make money. Period. That is their sole reason for existence. And they make money by selling you power. And you with your few little solar panels? They hateyou. You are an existential threat to their existence. Every watt of power you generate yourself is a watt of power they can’t make a profit from by selling to you. Every watt of power you try to sell them is, at best, an inconvenience to them and at worst, something that actually costs them money.
What it boils down to is that the utility company is not your friend. All of that PR fluff and nonsense about them caring about renewable energy and being environmentally friendly and caring so much about solar and wind power? It’s BS. All of it. Pure, unadulterated bull shit.
They will buy your power. If they are forced to by law. But they don’t like it, and they will put as many obstacles in your path that they possibly can. There will be special “fees”, special equipment requirements, special electrical code requirements and I don’t know what all else that are designed specifically to make it as difficult as possible for you to hook your system into the grid to sell them power. In a lot of cases the utilities actively bribe lobby state legislatures to change zoning laws, change permitting processes, change building codes and everything else they can to make it difficult or even impossible for you to sell power back to them.
And even if you do manage to jump through all of the hoops and force them to do it, there’s no guarantee that the rules won’t change tomorrow or next month or next year.
If you can manage to pull it off, good for you. But personally I’m not even going to try. I have no desire to sell power back to the utility. I want to become more independent from the utility company, not tie myself to it even more tightly.
Let’s talk about the grid for a moment.
One of the reasons I started to look into a system like this is because I am not optimistic about the sustainability of this country’s electrical distribution system and power generating capabilities. We are in the process of an enormous change in this country, switching from internal combustion engine powered vehicles and other ICE powered equipment, to vehicles and equipment that is powered by electricity. I am not opposed to this. I think it is a good idea for a variety of reasons.
The problem is that we aren’t ready for it. The electric grid in this country is already so stressed that even relatively minor weather events like a mild heat wave brings the grid to its knees. And now we are embarking on adding tens of millions of electric vehicles and other electrical demands to a system that is already strained to the breaking point. We simply do not have enough electrical generating capacity, first of all. And even if we did, the distribution system, the power lines, sub stations, etc. that distribute that power around the country, is old, rickety, and utterly inadequate to carry the amount of power it will need to deal with in the near future.
Last summer California announced proudly that it was going to ban the sales of ICE powered cars in the near future, as well as the sale of new lawn and garden equipment and other equipment powered by small internal combustion engines. And just days later, the state was forced to issue emergency instructions begging people tonotplug in their EVs to charge them because the grid was strained to the breaking point and they’d have to begin rolling blackouts to reduce the load if people didn’t curb their electric use. Same thing happened here in Wisconsin this past winter, although for different reasons.
We need to upgrade the electrical distribution system. We need to add more electric generating capacity. And we need to do it right now. And no one seems to be in all that big of a hurry to do anything about it.
This is another one of the reasons I am putting in this system, to get at least some kind of independence from the grid, not just to save money on my electric bill. Am I being paranoid? Maybe? But I think the problem is serious enough that I want to take some kind of precautions.
Anyway that’s for this time. Next time I’ll go into some detail about this system.
The weather finally got nice enough to let me get some chores done outside. First thing I had to do was get the solar panels up off the mud. I threw together some temporary frames and supports out of pressure treated lumber. I’m not putting in anything even semi-permanent yet because it’s all going to get changed around and more panels purchased in the near future to feed the new solar system we’re going to be installing. More about that a bit later.
The new setup seems to have made a huge difference in power production. I didn’t get this set up until early afternoon and at that time we were seeing high clouds that were cutting power production, but even with the clouds I was getting 500 watts or more. When the sky did clear momentarily they were peeking at around 750W for a time. At 4:30 PM after the skies had cleared I was still getting about 450W. For most of the afternoon I was running the entire basement, my radio equipment, the grow lights for our seedlings and the heating pad for the little greenhouse we have set up in the basement, the chest freezer and the living room, all running off the Bluetti with more than enough power coming in to run all of that and keep the batteries topped off. Of course there isn’t a heck of a lot of power being used for any of that. I think that peaks at around 600W of load. Still, that’s 600 watts of power we aren’t paying the utility company for.
Today is supposed to be warm and sunny so I’ll see just how much power those panels produce now that they’re more properly oriented. I am really pleased with those HQST panels. They’ve been doing much, much better than i anticipated.
The weather was so nice yesterday that I finally got the bike out of storage, checked over and out on the road again. After about 5+ months of a woefully sedentary lifestyle I was pretty stiff and after about five miles my legs were complaining already. The Vado up there may be an e-bike but it doesn’t do all the work for me. I still have to pedal it and I run it in “eco” mode so it only does about 25% of the work for me. Although I admit I will kick the assistance level when I’m going up a steep hill. Hey, what can I say? I’m old. I’ll be hitting 70 this year.
It was nice to get out on the road again on the bike but there isn’t much to see this time of year. The countryside around here is still mostly, well, looking like this…
Not very appealing but give it a few weeks.
The weather has been, as usual, odd. We went from rainy, cloudy, cold weather with daytime highs of around 40, to 70+ degrees literally overnight. It’s supposed to hit 80 degrees this week before the temps plunge back down into the low 40s again by the weekend.
And now the OMG part…
We made the decision to go ahead and make a significant investment in equipment for a rather large solar power system. I’ll go into all of the details later but we’re sinking a significant amount of money and effort into this and I hope it isn’t going to turn into a fiasco. We’ll see.
I thought I was going to have some time to prep for this. The company I’m buying the stuff from said it would probably take 2 – 3 weeks to put the order together, get it on a truck and ship it here. So no big rush in preparing. I need to clear space out in the basement, a difficult job because our basement is packed with stuff, a lot of which belongs to eldest son, and a lot of it is electronics so it just can’t be shoved down into the storage unit. And because of the condition of our basement there are limited places where a large electrical system can be installed. It’s going to take a long time to clear out space for it. And then I need to get miscellaneous parts like fuses, electrical cable of different types. a new transfer switch or lockout system for the main breaker panel… The list goes on and on.
So I thought I had at least two weeks to get ready for this. I don’t. It’s coming Monday. Something like 500 pounds of stuff on two pallets is going to get dumped off in my driveway sometime on Monday, I’m told. Or at least that’s the projected delivery date according to the shipping company.
The weather here in Wisconsin can get interesting, to say the least. Mostly it’s fairly pleasant up here, but sometimes things get weird. Like blizzards in May. Or the Great Frog Storm of 1956. (That one was scary.) This winter has been remarkably mild with very little snow. Well very little snow until now. I think we got more snow in the first 2 weeks in March than we did during the rest of the winter combined. Now we’re under a storm warning for tomorrow and could get another 5 – 8 inches of snow. Sigh…
But let’s get on with this. I’m sure you have better things to do than listen to me rambling along. I know I do. (Looks at calendar… Well no, it seems I don’t have better things to do. Never mind.)
I thought I was done talking about solar and power systems and all of that for a while. I should have known better because here we go again. That transfer switch I was talking about last time is now installed and working. The kit had everything necessary and installing it is pretty simple. It took maybe an hour to install the whole thing. (Do I really need to include the disclaimer telling you not to go fiddling around with your house’s electrical service because you can get killed if you don’t know what you’re doing?)
It took some time to track down what breakers powered what. A variety of electricians have been in that panel fiddling with things in the years we’ve lived here and not all of them were careful about labeling what they hooked to what, it seems. I was upset by that because these guys are supposed to be professionals. You don’t just shove a new breaker into a panel, hook it to something and leave it unlabeled. Or, even worse, change an existing circuit and then not note down what was changed. I ended up spending a good hour with a circuit tracer running around the house testing outlets and lights before I could even start installing the transfer switch. Fortunately only two or three were mislabeled but that was still concerning. I got out my little label making thingie to make nice, neat labels, only to find my label making thingie didn’t work. (Yeah, it’s been one of those weeks so far. The label maker, the mislabeled circuits, a crimping tool designed to crimp MP4 connectors doesn’t actually crimp things…)
With the transfer switch set up I can change between grid power and the Blutetti with just the flip of a switch. And the transfer switch doesn’t care where it gets power from so I can plug in either the Bluetti or our big Generac gas powered generator.
Planning and Research Problems
If you’ve been following this discussion that started with the Bluetti solar generator thing you know MrsGF and I have decided to put in a relatively large solar power system that can handle much of our electrical needs. We aren’t going “off grid” as they call it because with the weather we get here in Wisconsin it would be difficult, even impossible, to rely on solar for all of our electrical needs. But we could make a significant dent in our electric bill if we manage to pull this off.
But there are problems.
Now we could do something like look at some of the “plug ‘n play” systems from Bluetti, Ecoflow, Generac and others but all of those have serious issues. When it comes to the solar generator people like Bluetti and Ecoflow, the problem is that while they have some pretty nice systems that are fairly easy to install that can handle almost the whole house, you’re locked into those companies for the entire lifetime of the system. You can only use their batteries, their accessories, their adaptors, etc. If something goes wrong with the system the only thing you can do is pack the whole thing up and ship it back to the company which will, maybe, you hope, fix it and maybe, you hope, actually ship it back to you and that it will actually work when it arrives. And that will take weeks at least, maybe even months. And during that time your entire solar energy system is shut down. And let’s be honest, all of the systems from those companies are breathtakingly overpriced when you look at what you actually get for your money.
There are problems with the big brand names like Generac and Tesla as well. Once again you’re at the mercy of a single vendor for all of your equipment. You might be lucky and be in an area that is served by an installer/dealer who can help you when something goes wrong, and something will go wrong eventually, but even so you’re still tied to a single vendor for everything. And even worse, the systems from these companies are eye wateringly expensive for what you get.
And then there are the problems with almost all of the commercial “solar contractors” out there.
If your goal is to gain some independence from the grid you aren’t going to get it from most of the commercial solar contractors out there. What most of them are selling are systems intended to generate power that is sold directly back to the utility, not to make you independent from the grid. They have little, if any, battery backup capability. And with a system like that you are entirely at the mercy of the utility company. They could decide tomorrow to change the rates, add in bogus “connection fees”, even shut you down entirely.
So if you want a system that gives you some independence from the grid, that doesn’t lock you into a single vendor who could very well disappear tomorrow, want to do it as economically as possible, and want a system that is relatively easy to repair when things go wrong, you’re pretty much stuck with trying to build it yourself.
Which brings me to…
The Great Solar System Build
Oh, brother, talk about hyperbole. Sheesh…
Over the next few weeks (or months, because I’m not only lazy I am also a procrastinator of the first order) I’m going to document in excruciating and incredibly boring detail our efforts to build a reasonably large home solar power system from the ground up, complete with system specifications and why we chose those specifications, the search for equipment, dealing with various vendors, issues with wiring and building codes, etc, etc, etc.
For those of you who find this kind of thing eye wateringly boring, well, you have my sympathy. So posts about the solar system will be prominently labeled with a GSSB tag in the title so you can skip those parts and just drop in to look at photos or read the other nonsense I babble about here.
I was going to wrap up this whole Bluetti/solar generator discussion last time but some additional stuff came in email (email@example.com) and other sources, so let’s get on with this.
A couple of people have apparently been spending way too much time on YouTube watching people deliberately blowing up lithium battery packs and expressed the opinion that having a lithium battery in your home is the equivalent of having a rather large bomb waiting to go off at any moment. I won’t bother to point out that there are literally hundreds of millions of lithium batteries out here in the real world that somehow have managed to not blow up or suffer from “runaway thermal events” as they call it. Instead I’ll just mention that the batteries in the Bluetti and in many of these systems use LiFePo battery chemistry which is not only much safer, it also gives the batteries a much longer lifespan. I’ve seen LiFePo batteries being beaten with hammers and rocks, drilled through multiple times, stabbed with fishing spear, had nails driven through them, etc. and none of them exploded or turned into unquenchable blowtorches. They will get hot, they will vent gasses that I would very much want to avoid breathing, but none of them got explody or anything like that. If treated reasonably well LiFePo batteries could potentially continue to work well for years.
I got questions from a couple of people who have a power station or are thinking of getting one and don’t want to have to run extension cords all over the house in order to keep things running during a blackout. Why can’t you just use your house’s existing wiring system? Well you can, sort of. If you look at that photo of the AC200Max over there you’ll see a very large 3 prong socket on the far right. That’s a TT-30 plug, a high amperage connector. Well, sort of high amperage. If I remember right it’s only good for about 20 Amps because of the limitations of the AC200Max’s inverter. It’s intended to feed power to the electrical system of an RV but there’s no reason you can’t use that to supply larger amounts of power to a transfer switch system to feed selected circuits in your home without having to run extension cords everywhere.
So that takes care of… Uh? What’s a transfer switch? Ah I suppose I’m going to have to explain that now.
Okay, here’s the deal. You can’t just pump power from an external generator into your house’s electrical system. If you try most of your power is going to backfeed into the grid, overloading your generator and quite possibly killing some poor lineman working on a pole somewhere trying to restore power during a blackout. And you are not permitted to just shut off the main breaker on your electrical panel, either. In a lot of jurisdictions it is flat out illegal to hook any kind of alternative power source to your house’s wiring without the installation of some kind of transfer switch system.
And here’s an example of one.
That is a Reliance transfer switch kit that I picked up at a local home improvement store for about $300. These things are designed to allow you to take up to 6 individual circuits in your home and let you switch them to work with an external power supply like a generator or something like the Bluetti. A BAC (Big Ass Cable) plugs into the big socket on your generator, and the other end plugs into a BAP (Big Ass Plug) wired into the transfer switch. When you flip the switches on the box up there, you switch that circuit from the LINE, which is your connection to the grid, to the GEN input, which is fed by your generator.
And no, I’m not going to give you instructions on how to install one because I don’t want to be responsible for you electrocuting yourself or starting your house on fire or something like that. These things aren’t hard to put in. There are numerous videos out there showing you exactly how to do it. But I am going to put in the usual disclaimer that you shouldn’t go fiddling around in your circuit breaker box because you can kill yourself or someone else, burn down your house or damage equipment if you don’t know what you’re doing. In a lot of jurisdictions it’s technically illegal for you to do so. Legally you may need to get a permit, hire an actual real electrician to do the work, have it inspected, etc. before you can use one of these. So I’ll leave it at that.
During the weekly staff meeting here at the palatial offices of grouchyfarmer.com someone brought up the topic of maybe looking into some tax credits or something if we did a solar power system, so we’re looking into that to help offset the cost of putting in a 10 – 15 KWh battery system with something like a 8 KW or larger inverter fed with 48V batteries. We’re currently in the planning phase of that. With our electric bill running $300/month here, a decent tax credit and other factors it’s beginning to look as if it might make sense economically to install such a system to take at least part of the house’s needs off the grid.
We already have most of our garden planning done, all the seeds bought already, and are just waiting for the weather to get better so we can get out there and start puttering around in the dirt again. We have a lot of plans, but whether or not any of it will actually get done is something else again. Some of the plans are on the expensive side and if we go ahead with the solar project that might eat up a lot of our discretionary budget for the year. So we’ll see.
I want to do one last article about the Bluetti AC200Max before I move on to other things. I’ve been doing a lot of research into solar power systems, have my own solar power system up now, well, sort of, and I wanted to talk about trying to use one of these in an off-grid situation.
First, though, grouchyfarmer.com has a new email address. It is firstname.lastname@example.org. If you have questions or comments about any of the stuff you see here or even suggestions for future articles you can reach me at that address.
Now let’s get on with what I hope will be the last Bluetti article for a while. I’ve tested this thing with one B300 3KWh expansion battery (you can add two of them) and it’s handled everything I’ve thrown at it. It is working exactly as advertised and I’m very pleased with it. With the extra cost B300 ($2,300) battery it now has 5KWh of power. Preliminary testing indicates that it could keep the furnace going for at least 24 hours, maybe as long as 36 hours. And it will keep our sump pumps going for 2 – 4 hours in heavy spring rains depending on weather conditions.
But one thing I didn’t talk about much was recharging this beast. 5 KWh is a hell of a lot of energy to pump into a battery pack and eventually this thing has to be recharged. That’s where I start to run into what could be potential bottlenecks for some people, especially someone trying to use this as their primary power supply in an off-grid situation.
It comes standard with a big AC charging brick that will put 450W into this unit to recharge it. That’s a lot, but this is also a massive battery which means it’s going to take a considerable amount of time to fill it up from empty. With my system it would take the AC charger alone more than 11 hours to fully recharge it. If I had the 2nd battery pack for a total of 8KWh it would take almost 18 hours to do a full charge. Frankly I think that’s woefully inadequate.
Now I could fudge and fiddle around. The B300 battery has its own AC charging port.I could get a second AC charger and dump another 450W into the battery independently of the AC200Max to get a total 0f 900W AC charging. That would bring the charge time for my 5KWh system down to about five and a half hours.
But they call these things “solar generators”. Where the hell is the solar part of all of this?
Well you generally don’t get the part that actually makes it a solar generator, the solar panels. Those are an extra cost option. Companies like Jackery and Bluetti will gladly sell you their own branded portable folding solar panels. For a price. A really, really big price. Generally two or three times what it would cost you to get the same wattage in generic panels you bought off Amazon or somewhere. Here’s an example.
Bluetti will sell you this:
That’s the PV350. It’s a folding panel intended for temporary use. It folds up into a nice neat package, gives you up to 350 watts of power to dump into your Bluetti, and from all the reviews I’ve seen of it, it is very, very nice.
But dear lord, that price!!! $850 for only 350 watts of power? Seriously? And I’d need two of these things because with just one of them it would take 15 hours to recharge my system. It’s winter here in Wisconsin. The days are short, the sun is low in the sky. We often have clouds. With just one of these panels it would take something like three days to fully charge my system in the winter. And that’s if I wasn’t using the system to power something. Even with two of these panels it would take me more than a day to recharge because I only get about 5-6 hours of usable sunlight a day this time of year.
So I did some shopping around and a great deal of research and finally came up with these:
That’s a set of 4, 100W panels from a company called HQST. So I could get two four panel sets for a total of 800 watts for $550, or I could get two PV350 for a total of 700W for $1,700.
Guess what I bought? Damn right. I may be crazy but I’m not stupid.
And the panels themselves are actually really nice. They’re well made, sturdy, small enough and light enough to be easy to handle. And best of all, they work pretty much exactly as the company claims they do. And I now have all 8 of them outside leaning up against the south side of my garage all hooked up and feeding power into the basement.
Hooking up solar panels is about as easy as it gets. Most of them come equipped with MP4 connectors that just snap together. It’s pretty much impossible to wire them wrong. They just daisy chain together in series, plug in the cable to go to the basement. The AC200Max comes with a pigtail that has MP4 connectors on one end to go to the solar panels, and a T90 connector on the other that plugs into the AC2ooMax. And that’s all there was to it. It took me less than half an hour to set up six panels, hook them together, run a cable into the basement, plug it into the Bluetti and start sucking up all that yummy free solar power.
Well, sort of. I ran into some limitations which kept me from using all 8 panels, but let me tell you about the realities of solar power first of all.
The first thing I learned is that I will almost never get the maximum rated power out of those solar panels. Oh, they don’t lie when they give you those numbers. But you need to remember that those ratings are done in a laboratory under ideal conditions. Conditions that you will almost never see out in the real world. Especially not in Wisconsin. In February. I had 600W of panels out there but the maximum I was getting out of them was about 400W, and that was only for a couple of hours around midday.
Still, the system was working. I tried running my office/radio shack/mad scientist’s lab in the basement off the Bluetti and feeding it power from the solar panels and it worked quite well. By about 9:30 in the morning those six panels were producing enough power to run my little office, about 240W, that would gradually go up during the day, peaking at midday around 400+ watts in perfect weather, then dwindle until about 3 when power production shrank to under 100W. I was running my office entirely off those panels alone for about 3 or four hours in good weather.
Why Only Six Panels
Okay, let’s deal with that situation. The AC200Max has a built in solar charge controller. It is rated at up to 900W, 145V, 15A. Those are the maximum numbers it can handle. If you exceed those inputs by more than a small amount either the system just won’t use the extra or, even worse, the charger will just shut down to protect itself.
So now we need to do some math. Don’t worry. It won’t hurt. Much.
My panels were hooked in series, like in this diagram below.
It’s quick, it’s simple, and it works well. But as you can see from the diagram when panels are hooked together in series the voltage of each panel you add to the string is added to the voltage previous panels, and eventually you get to a voltage that the charge controller can’t handle.
My HQST panels have an open circuit voltage of 21.6. Six panels in series gives me a voltage of 129.6. The AC200max can handle 145V so that’s just fine. But if I add a seventh panel? 129.6+21.6=151.2. And 151V is over the 145V limit. So I can’t have more than 6 of these panels in series without going over the limit.
So how can I stuff more watts into this beastie without going over that limit? This is where parallel wiring comes along. Here’s another diagram for you to look at.
When connected in parallel, the amperage of each panel adds up, while the voltage stays the same. My panels have an amp rating of 5.5. So I could put two panels in parallel and remain under the 15A max rating of the Bluetti. In effect I’d have a single 200W panel producing just 21.6V at 11A, well within the Bluetti’s limitations.
So I started doodling and came up with this.
I’d create 4 banks of two panels each connected in parallel. Each bank would have 21.6V and 11A. Then I’d connect all 4 banks in series. That would give me all 800 watts they could produce, I’d have a voltage of 86.4, and my amperage would be 11. Of course I didn’t have the right connectors to do that and I’d need some extra cable so it was off to Amazon and a few more bucks and a couple of days later that stuff arrived and I spent a half hour or so switching from series wiring to my parallel/series sketch, hooked everything up this morning.
Then the moment of truth came. I crossed my fingers, held my breath and plugged it into the Bluetti and… And it worked? Wait, it actually worked???
Yeah. It worked. I was getting about 80V, the amperage looked good and the watts coming in… Well okay I was only getting 80W but it was 7:30 in the morning and the panels were still mostly in shadow. By 9:30 they were making 300W and by noon I was getting between 650 – 700 watts! Damn, it works!
As I said before my conditions here for solar are far from ideal, so seeing those 800W of panels peaking at 700 watts at midday was very satisfying.
And on the charging side of things? If I were drawing no power at all from the Bluetti and could get a consistent 700W solar input I could charge my 5Kwh system in a bit over 7 hours, which isn’t … Well I was going to say it isn’t bad, and I suppose it isn’t absolutely horrible but I only get useable sunlight here for about 5 – 6 hours a day this time of year, so it would take me more than a day to recharge this thing.
The Problems With Going Off Grid
Now let’s talk about going off grid. If you start scrounging around on YouTube and places like that you’ll run into videos from people who claim you can use the AC200Max like mine to go off-grid, using it as your primary source of power to run a small house or cabin or whatever, and replenishing the power you use entirely with solar. I have the Bluetti with 5KWh of power stored in it. I have all those solar panels. Why not try to run part of the house off grid and see what happens? So I’ve been experimenting with running my office/radio shack/mad scientist’s lab off the AC200Max and keeping it charged with just solar. And I’ll tell you right up front that it ain’t gonna work. I’m sorry, but it isn’t. At least not in the real world. Not without having to resort to some kind of additional power inputs from either the traditional grid or a backup generator of some sort. The numbers just don’t work. I knew that even before I started the experiment but I decided to try it anyway just to get some real world experience with the system.
My office uses about 270W of power as long as I’m not using my laser engraver or other energy hog piece of equipment. Just to keep things simple let’s round that up to 300W. That means that if I run my office for 10 hours I’d use 3,000Wh, with 2,000Wh remaining in the Bluetti.
So it’s the morning of the next day. I need to recover that 3KWh of energy I used the previous day. I have 800W of solar power but that only peaks at about 700W. But that’s not too bad. 7ooW of solar going into the system would recover that 3KWh in a bit over 4 hours. Great.
Well, no, not so great. First of all I only get those 700 watts for an hour or maybe two, during midday. The rest of the time I’m getting much less than that.
Second, I’m still running my office off that system. I’m not going to shut down for 4 hours to recharge the batteries. So even as I’m trying to recharge it, I’m drawing 270W. Even if I were getting 700W of power out of the panels, I only have a net gain of 430W. Recovering 3,000Wh with an input of only 430W gives a time of about 7 hours.
And I only get about 5 hours of usable sunlight a day this time of year.
And that’s with a load of only 270W. If you’re trying to use this system as your primary source of power running a furnace, refrigerator, some lights, etc. you’re going to be drawing considerably more than that.
So as I said, the numbers just don’t add up. This time of year, with the conditions I have here, with the amount of daylight I have here, I am never, ever, going to be able to get ahead with the amount of energy my solar system puts out. Even if I could max out my solar and put together a system that would pump the 900W maximum into the Bluetti it wouldn’t work. That would give me a net gain of 630W, and I’d get 3KWh out of the system in about 5 hours. But that’s assuming I’d get all 900W for that entire 5 hour period. And I won’t. Not even close. Not in Wisconsin, in February. With the standard solar charging system in the Bluetti I simply cannot dump enough power into it, fast enough, to get ahead.
Is there a way I can fudge things? Well, yeah. Sort of. The B300 expansion battery has its own solar charger built into it. Granted it is a pathetically wimpy one, only able to handle 200W. Trying to charge a 3KWh battery with 20oW is sort of like trying to fill a bathtub with a teacup, but it’s better than nothing. And if I’d add that into the 900W theoretical max I could dump into the AC200Max: 900 + 200 = 1,100W. 1,100 – 270 = 830. I’d now have a net gain of 830W. That gets us down to a bit less than 4 hours to recharge my system.
Now I’m finally seeing some numbers that almost make sense. Well, in July. In February I only have 5 hours of usable sun and I’m not going to get anywhere near peak production so I’m still going to be running at a net loss most of the day.
Bluetti will sell you a gadget they call a DC charge enhancer for $200. That would let me dump up to another 500W of solar into the AC200Max through its AC charging port. I build myself a third solar panel system, this one with 500W. I plug that into the charge enhancer, and that plugs into the AC charging port of the AC200Max giving me another 500W. 900 into the AC200 +200 going into the B300 battery +500 going into the charge enhancer = 1,600. 1600 minus my power consumption, 270W gives me a net gain of 1,330W. Now I’m looking at recovering those 3,000W in about two and a half hours.
Now, finally, I’m seeing numbers that would let me get ahead of the game. Peak solar production is only for around 2 hours at midday. But that, together with producing a bit more solar than I’m consuming the rest of the 5-6 hours of useable daylight I have, might get me to the break even point or even a bit better.
But only at the cost of building two additional solar panel systems, that $200 DC charge enhancer, cables, connectors, etc. But it should work.
Well until you get a day like today where we have solid cloud cover and my 800 watts of solar panels are putting out a whopping 80 watts of power.
So could you go off grid with the AC200Max and a couple of the expansion batteries? Uh, well, maybe? If your total power consumption was less than about 5KWh or so per day, and if you max out solar production by building extra solar arrays and adding in the DC charge enhancer and if you had perfect weather conditions to max out solar production.
But out here in the real world? No. Not without having to resort to some kind of alternative power source like a gas generator to help along in bad weather or help to cover unexpected power demands.
This particular system is great at what it is intended for, which is being a relatively short term power replacement during grid failures or to provide power for an RV or camper. It is not intended for use as an off grid system, long term, primary power system.
One more bit about solar power systems before I shut down this discussion and get back to more important things like fiddling around with gardens and photography and plants or wood and stuff.
Bluetti, Ecoflow and a few other companies make absolutely massive power systems that are intended to provide power for almost an entire home for lengthy periods of time. Some of them offer up to 18KWh. Eighteen thousand watt hours of power. If you really want to go off grid should you consider one of those?
Frankly, no. Those massive beasts look tempting, even will give you true 240V split phase systems. But the prices are just as massive as the battery packs. We’re getting up into price ranges and amounts of power where you should be seriously considering contacting a professional solar system contractor. A fully loaded AC500 system from Bluetti is going to be pushing $15,000, and that’s without a solar system to keep it fed.
And here’s another thing to consider. There’s no reason why you couldn’t save yourself a lot of money and build your own. LiFePo batteries have really come down in price. You can get a 2KWh or larger LiFePo battery for less than $700. You can get inverters that will handle a heck of a lot more than the 2,000W version in my AC200Max. You can get solar charge controllers to handle just about any configuration of solar panels and batteries you can build. And you can put it together with all off the shelf parts. And you can do it for a heck of a lot less than these plug ‘n play systems from Ecoflow, Bluetti and the others.
I’m seriously considering doing just that, covering the south facing garage roof with a couple of kilowatts of solar panels, putting a bank of LiFePo batteries in, getting a big inverter, and setting up a separate power panel in the basement to feed selected circuits in the house.
So, I have good news, and I have good news. Very good for a change.
First, regarding Bluetti customer service: Not only did I get a positive response from the company’s regular customer service department that was actually helpful, this morning I got an email from an actual engineer at the company to discuss specifics about the problems I encountered. As noted before the voltage fluctuation problem went away by itself but they’re concerned about that light flickering and wanted specific information about the brand, model and other details about that light so they could look into it. That’s not a big issue though because I believe the problem is related to that particular model light and that one only. All the others I tested had no problems. I suspect it is an issue with the design of that light fixture.
So that makes me feel a lot better when it comes to customer service.
My solar panels arrived! I ordered 4, 100W panels from a company called HQST mainly because they were very cheap. And it turns out that not only were they very cheap, they’re very good as well. It took me all of about 10 minutes to set them up leaning against the backside of the garage, one of them shaded by that stupid bush out there. And at the moment I’m getting almost 300 watts out of them (hooked in series) If I didn’t have that one panel being partly shaded and had them at the right angle relative to the sun I’d be getting close to the full 400 watts out of them. So I’m enormously pleased with that too.
Right now I’m getting between 250 – 300 watts out of ’em. We have some intermittent high, thin clouds that shade them out a bit which is why there is the fluctuation in output. I’m drawing 190W in the office at the moment running my laptop with 2 monitors, stereo speakers and a few other things, so the panels are making about 100W more than what I’m consuming here in the office.
I tried dual charging the AC200 as well, charging with the AC200Max’s AC charger and the solar panels and it was happily sucking down about 750 – 800 watts from both sources at the same time.
So I am enormously pleased. (Squeals like small child)