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Help with home battery backup system

Yeah, that was my mistake earlier. Other participants in this thread corrected me, and what I meant to say was 15kW. I took all our "must-haves," estimated the amount of time each would have to run, added them together, then added another 25% on top for overhead to last two days.
I figured you had it handled, but I think you swapped the units again.
 
...some were saying that it's possible for the phases to get unbalanced, and the unit shuts down in protection mode.
There's a video about it that might help.

The issue is a split-phase power issue. In North America and a few other places the power is what's known as "split-phase".

Off the power pole coming into the house, most people have 3 wires commonly called L1 (aka leg 1), L2, and neutral. Voltages from L1 or L2 to neutral is 120V, and voltage from L1 to L2 is 240V. In your fusebox, the breakers that are two breakers thick are 240V, the skinny ones are all 120V. This allows most of the house to have lower voltage and be "safer". EU, Austrailia, and most other places are single phase 220V.

Ideally, if a house is usually pulling 10 amps, the electrician wires it targeting to have 5 amps on L1 and 5 amps on L2. Or they should, but it's not that big of a deal while on grid. But, if a 12 kW inverter can only put 6 kW on L1 and 6 kW on L2, an owner is sometimes surprised they can't get 12 kW on a single leg.

In the Sol-Ark 12K case, it's rated for a maximum 240V current of 33 Amps (9 kW) and a maximum 120V current of 40 amps (4.8 kW). So, if a 120V pump has an inrush of 60 amps (7.2 kW), it's likely the inverter will reset rather than supply the power. A neutral forming transformed can be used to help shift some power between legs, but you take an inefficiency penalty.

...Apparently the Sol-Ark is beefy enough to be installed in front of the main...
Be careful about that. You might only be pulling a few kW in "survival" mode, but in normal use, with a dishwasher, washing machine, air conditioner, TV, computers, etc. the loads can be quite high for brief periods. Most homes have 200 amp meters and a 150 to 200 amp rated fuse box.

In the Sol-Ark 12K case, it's rated for a 50 amp passthrough, which is a far cry from the normal 200 amps.
 
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Off the power pole coming into the house, most people have 3 wires commonly called L1 (aka leg 1), L2, and neutral. Voltages from L1 or L2 to neutral is 120V, and voltage from L1 to L2 is 240V. In your fusebox, the breakers that are two breakers thick are 240V, the skinny ones are all 120V. This allows most of the house to have lower voltage and be "safer". EU, Austrailia, and most other places are single phase 220V.
Based on the description of the OP where his subpanel has two 20 amp breakers ganged together feeding his well pump I would assume his pump is 240v. He seems to think it is 120v and that the sub panel is only 120v. Would not make any sense if his description was accurate.

That is why I told him that his pump was unlikely to be 3hp. 20 amps is what you would find for a 3/4 to 1hp 230v pump.
 
Thank you again, svetz and Mattb4! There really isn't much user-content out there about the Sol-Ark 15k, so I was commenting on the "beefy" supposed nature of that product vs. the user-content critiques of the 12k. I assumed the 15k was more powerful and could handle placing ahead of the main? I thought I understood correctly when I watched a couple of install videos on YT. Great info on the split-phase problem.

I had no idea that you could have both 110v and 240v off the same panel. Gosh, the more I'm learning on this forum, the more I realize what I DON'T know could cause me to undersize the system, or make other critical mistakes. There just is no one local here for me to help with this research. I'm losing confidence...
 
Someone over on the Sol-Ark 15k thread just made a great point. Even though the unit doesn't need a transfer switch, he's going to install one anyway. If the unit goes down while there's grid service, he won't have to lose the house while he waits for it to be serviced/repaired...just throw the transfer switch.
 
Someone over on the Sol-Ark 15k thread just made a great point. Even though the unit doesn't need a transfer switch, he's going to install one anyway. If the unit goes down while there's grid service, he won't have to lose the house while he waits for it to be serviced/repaired...just throw the transfer switch.
That or a critical-circuits panel are the normal routes.

Update: Danke reports the 15K has a 200 amp pass-through.
The 15k is probably limited to a total passthrough of ~62 amps, so I wouldn't put it between the meter and fuse box. I normally don't pull more than 8 amps total. But the hot water heater kicking on at the same time as the microwave and AC, that's a lot of amps. With a transfer switch you can still feed into your main panel, but in survival mode you'd want to turn on/off circuit breakers depending upon what you want to run balanced against power and energy.
 
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Someone over on the Sol-Ark 15k thread just made a great point. Even though the unit doesn't need a transfer switch, he's going to install one anyway. If the unit goes down while there's grid service, he won't have to lose the house while he waits for it to be serviced/repaired...just throw the transfer switch.

I’d like to see how he is wiring the main panel. Two lines into one lug? Or some sort of switchable (additional transfer?) terminal block?

I’m using a transfer switch after meter to be able to shut down power to inverter if I need to work on it. Still requires me to move wires to main panel before reconnecting, but in the meantime before work or replacement, I will still have full grid power via the pass through function of the 15k.
 
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That or a critical-circuits panel are the normal routes.

The 15k is probably limited to a total passthrough of ~62 amps, so I wouldn't put it between the meter and fuse box. I normally don't pull more than 8 amps total. But the hot water heater kicking on at the same time as the microwave and AC, that's a lot of amps. With a transfer switch you can still feed into your main panel, but in survival mode you'd want to turn on/off circuit breakers depending upon what you want to run balanced against power and energy.

Passthrough is 200A.
 
... Gosh, the more I'm learning on this forum, the more I realize what I DON'T know could cause me to undersize the system, or make other critical mistakes. There just is no one local here for me to help with this research. I'm losing confidence...
Nothing wrong with knowing that you do not know enough and need help. The problem as you say is that you lack local professional help to accomplish your goal.

All I can recommend at this point is keep searching for a knowledgeable electrician in your area and do not buy anything before you have a good plan worked out. If nothing else your Thread here should help you understand if someone you hire is feeding you a line of BS.
 
I hate to bust your bubble on roof warranties but they are worthless as most companies will be out of business not even halfway through the warranty period.

Makes me also wonder about the 25 year warranty on PV producing 80% of ratings.

Especially with panels from Chinese companies. Will they be around to honor warranty?

Are we confident on the lifespan of panels?
 
An update on where I'm at:

I went to Harbor Freight to look at the clamp-type current meters. Price range from about $25 to $100...my eyes glazed over, and I didn't know what I was looking at. Before going, I had tried reading instructions online how to calculate amps from a clamp meter, and didn't understand the process. (I think it described poking the probes through the insulation, too. I don't want to do that!) I guess I'm going to have to pay to have someone who knows what they're doing check the well pump for me.

I did, however, buy a Kill-A-Watt. I can't check everything, but at least I can check off a few boxes on our must-have power list. The first thing I checked was the chest freezer. I left it on for 24 hours, and it only consumed 850 watts. This afternoon, I switched to our side-by-side refrig/freezer. It's been on for five hours, including a defrost cycle, and I'm at about 800 watts. Looks like it will come in around 4kW for 24 hours...maybe a little less. I haven't been able to catch it when it starts up, to see what the starting amps are. Online searching says about 15 amps.

Next I'll probably check my greenhouse exhaust fan, and I may try to do the lift station pump, although it runs so infrequently, I'm not sure I want to leave the Kill-A-Watt outside for that long. That's it for the heaviest power draws on our must-have list.

That darn well pump is the kicker, though.
 
I did, however, buy a Kill-A-Watt. I can't check everything, but at least I can check off a few boxes on our must-have power list. The first thing I checked was the chest freezer. I left it on for 24 hours, and it only consumed 850 watts.
I presume you mean 850 Wh (watt.hours). Chest freezers are generally a pretty efficient design for keeping stuff cold.

This afternoon, I switched to our side-by-side refrig/freezer. It's been on for five hours, including a defrost cycle, and I'm at about 800 watts. Looks like it will come in around 4kW for 24 hours...maybe a little less.
Ouch, 4 kWh/day is a lot for a domestic fridge.

Ours uses 1.4-1.5 kWh/day and while reasonably modern (< 10 years old) it's not a really nice super efficient model either.

Side by side door fridges are not a particularly energy efficient design. But that's what you have.

But it is great you have the Kill-a-Watt and can now get a decent understanding of the power and energy demands of your key appliances. It can be eye opening.
 
Ouch, 4 kWh/day is a lot for a domestic fridge.

Ours uses 1.4-1.5 kWh/day and while reasonably modern (< 10 years old) it's not a really nice super efficient model either.

Side by side door fridges are not a particularly energy efficient design. But that's what you have.

But it is great you have the Kill-a-Watt and can now get a decent understanding of the power and energy demands of your key appliances. It can be eye opening.
I shouldn't have guesstimated with only five hours into the test, and following a defrost cycle. At the 24-hour mark, the refrig/freezer finished with 2.67kW. I did discover that the back of the metal case of the side-by-side felt cold, so, I may buy some of that reflective bubble-wrap and use double-backed tape to help with the insulation.

Earlier in this thread, stienman also recommended a Growatt system, but I haven't had a lot of luck researching the specs on them. I just finished watching this video:
where the guy puts a Growatt and a 14kW Rhino battery through a ridiculous test, powering a bunch of things in his home covering 11 hours. At one point he spiked up to 130+ amps. He did note at the end it automatically switched back to grid power, but I don't know how sophisticated the ATS is.

Also, there are some "economies of scale" issues with rack-mount 5kW batteries vs. one giant battery...the price advantage going to the large, single battery. It weighs 375 pounds, so that's one HUGE disadvantage though. Thoughts?

What would be the obvious differences between a system like this and a Sol-Ark 15k with three SOK 5kw batteries? Anything of note with respect to my goal for it to simply power our home for ~ two days in an extended outage?
 
It weighs 375 pounds, so that's one HUGE disadvantage though. Thoughts?
I've got a couple of 100 Ah 51.2 V server rack batteries coming. I had the option of a 200 Ah unit but the weight put me off - it was just going to be to heavy a beast for me to move about and get into position. I'm reasonably strong but have a disability.
 
I shouldn't have guesstimated with only five hours into the test, and following a defrost cycle. At the 24-hour mark, the refrig/freezer finished with 2.67kW.
Good to have the data. That's better, still on the high side but that's what you have and at least you are thinking of ways to improve on that, but importantly you have the measurement device to know if it works. Door seals are an obvious issues with fridges, so pay attention to them.

In the future when the time comes to replace it, then you can shop with energy efficiency more at front of mind.
 
In the future when the time comes to replace it, then you can shop with energy efficiency more at front of mind.
We've had it serviced twice over the past 17 years we've lived here, replacing the heater element. I was told by the last serviceman to keep this one running as long as we can (it's a GE circa 2004). He said the newer models have lots of bells and whistles, but most of them need servicing after the 4-5 year mark, and many need major work approaching the 10-year mark equaling replacement value.

So, it's not as efficient on one end, but it's basically trouble-free and we don't have to worry about it failing if we're away from home.
 
Also, there are some "economies of scale" issues with rack-mount 5kW batteries vs. one giant battery...the price advantage going to the large, single battery. It weighs 375 pounds, so that's one HUGE disadvantage though. Thoughts?

That is actually more expensive than what I’ve seen of rack batteries.
 
That is actually more expensive than what I’ve seen of rack batteries.
Maybe you're right, if you factor in the shipping. I think they want $800 and change to ship the Rhino, I think the rack mount batteries were around $200 apiece to ship? But then, with only three rack mount batteries, you'd also have to pony up for the server rack.

Hmmm... Maybe it's not as big as difference as I thought. Probably better to have separate components that are easier to move around?
 
Maybe you're right, if you factor in the shipping. I think they want $800 and change to ship the Rhino, I think the rack mount batteries were around $200 apiece to ship? But then, with only three rack mount batteries, you'd also have to pony up for the server rack.

Hmmm... Maybe it's not as big as difference as I thought. Probably better to have separate components that are easier to move around?

I see they have a 20% off right now. So not as expensive as I thought.

A rack battery is ~$45 to ship. And unless you are buying a lot, don’t really need a rack. A rack is nice, but I just put mine on shelves.
 
[snip]

I'm going to do both. At present my off-grid all-in-one inverter provides power to designated home circuits via a manual transfer switch. This means when we want backup power I need to manually switch over. However I have the option of simply leaving the transfer switch "permanently" switched on the backup side. My AIO inverter is supplied with power via grid powered circuit and it can pass power though and operate as an automated backup as described by stienman (it also has a small off-grid PV array and of course the battery).

[snip
Can you tell me more about this setup? I just posted a new post on this forum, and your setup sounds like my option #3: https://diysolarforum.com/threads/b...-professionally-installed-in-1-2-years.53309/

Is it basically just a manual transfer switch installed in the completely normal way, but you keep the output of your inverter plugged into the input of the MTS? And you keep the MTS breakers in the "on" or "generator" position 24/7. But under normal conditions they are just being powered by the pass-through power from your inverter, and during grid outages, your inverter continues to power them but now from the batteries instead of from pass-through from your main panel?

Are there any major downsides to this setup? Sounds awesome to me but it does not seem to be very common. Many thanks for any input, and please feel free to reply in my thread linked above rather than reviving this older thread.
 
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