Is there a non-solar solution w/battery bank if single 240V/20A circuit is available?

[Living Large]

Hello SolarPanelTalkers. I lurked here for about 6 months a year ago, and designed a solar system with LFP batteries and generator for my cabin. At the end of that, Sunking woke me up with the question "why would you do it?" Long story short, we put in a 1700' line extension that crosses a creek to my cabin. Power will be installed within 2 weeks. Cost to me? About $6000 plus a heck of a lot of work. I appreciated everyone's help here in learning what it would take to design a system and use it, but am grateful I got the good stuff from the power company.

I have a different question about a different proposed building. Let's say I had 240V @ 20A available to me of solid POCO power from a neighboring source and I have a house that will consume 10kWH per day. Could solar panels be eliminated, and a battery bank power this hypothetical house and be recharged/maintained by the 20A 240V circuit? What equipment would be needed and what battery technology would be desired? I was considering LFP for my solar system because this is in a low sun hours location and I wanted quick charging, but that not a factor if there are no solar panels.

I know this is "solar panel" talk, but I also believe you can quickly out me on a course. Thank you. Don

[J.P.M.]

I have no answers/advice for you in your current matter, but welcome back. I wondered 1X/awhile how you made out. Booneville/environs surviving you ?

[ButchDeal]

You would need to know more about the loads. For example do you have a large load that runs for 1 hour and nothing else all day ( extreme example). But you could yes use an outback ( or other brand) bimodal inverter, with batteries to provide more power for short times and recharge from the line. You could latter add some solar to cut the draw if you like.

[Living Large]

You would need to know more about the loads. For example do you have a large load that runs for 1 hour and nothing else all day ( extreme example). But you could yes use an outback ( or other brand) bimodal inverter, with batteries to provide more power for short times and recharge from the line. You could latter add some solar to cut the draw if you like.

I don't envision a "large load" running for an hour. I wouldn't have something like an arc welder or run power equipment for long periods. Occasional use of shop equipment though, like table saw, etc. I don't need a huge central air system or anything like that. I may want a mini-split. Since I was solar-oriented, I would carry over some of that approach. One large load would be the well pump, but no watering of lawns and shouldn't run long periods (or real long showers )

I have to look into "bimodal inverters" which I only recall hearing mentioned here once. I'd like a generator backup that isn't too painful to implement. I don't know if this proposed system would lend itself to the same kind of transfer switch used in an on-grid house. Solar would be kind of icing on the cake. I'm looking for simpler, and sun is kind of hard to come by a lot of the time there. I do see that the main expense I would still have - the battery bank.

[Living Large]

Looking across creek at P9 P10.jpg

I have no answers/advice for you in your current matter, but welcome back. I wondered 1X/awhile how you made out. Booneville/environs surviving you ?

Hey J.P.M. I haven't spent a lot of time there. Power line will finally be installed next week. Pic is looking from my side of creek to a few new poles. There will be one more over there at the end of the path. It's a little scary around Boonville to an out of towner!

[inetdog]

If the 240V/20A is not enough, by itself, to power your largest loads, or if you anticipate a lot of smaller loads running at once and do not want to be bothered with power management you could do it.
But to be economically feasible you should try to design it so that any power needs up to that 4800W limit are supplied by the input A/C without discharging your batteries.
If you used a model which took all routine power loads from the battery bank and recharged in between power uses you would be overpaying for that power by using up your expensive battery bank just as you would be with a solar PV-only system.

[ButchDeal]

I don't envision a "large load" running for an hour. I wouldn't have something like an arc welder or run power equipment for long periods. Occasional use of shop equipment though, like table saw, etc. I don't need a huge central air system or anything like that. I may want a mini-split. Since I was solar-oriented, I would carry over some of that approach. One large load would be the well pump, but no watering of lawns and shouldn't run long periods (or real long showers )

I have to look into "bimodal inverters" which I only recall hearing mentioned here once. I'd like a generator backup that isn't too painful to implement. I don't know if this proposed system would lend itself to the same kind of transfer switch used in an on-grid house. Solar would be kind of icing on the cake. I'm looking for simpler, and sun is kind of hard to come by a lot of the time there. I do see that the main expense I would still have - the battery bank.

Table saw would be a big load. High start current and most require a dedicated 15a circuit ( small ones) and larger ones require a 20 a circuit.
Well pump likely would require your 20a 240v circuit. I use a flexpower 1 with auto transformer for the well pump. You could do something like this and use another auto transformer to convert the 20a 240v to 40 amp 120v.

[bcroe]

Any sort of moderate AC induction motor would overtax such a system on startup, and possibly
not receive adequate voltage (regulation) under heavy loads (saw a big board). If you ran with
DC or universal motors, you could run without damage (and possibly terrible regulation/efficiency).
I run an electric chain saw on a rather long extension with some loss of power, but no other issue.

Power management could have your pump filling a water tank/tower in the middle of the night,
sensitive stuff like an AC fridge would freeze up ice "storage" blocks at a time that nothing else
would drag down the line. Days go light, start a generator for heavy stuff. Don't use batteries.
Bruce Roe

[gbynum]

Any sort of moderate AC induction motor would overtax such a system on startup, ...
Bruce Roe

Bruce and OP, VFDs have become low enough in price to allow, with a 3 phase motor, startup current control to almost any level desired. If your saws can have single phase motors replaced economically and practically, limiting startup to full load is inherent in most. 1 HP (real), 230 3 phase out from 230 single in, $134 from Automation Direct. 2&3 HP is available at higher $$, but just by limiting how fast you cut, 1 HP would probably do.

[Logan5]

this device is meant to convert a dedicated mains 240 volt single phase circuit to 3 phase, w/o regards to efficiency and assuming it has unlimited source of 240v. sounds like a bad idea using batteries as your 240v source.

[jflorey2]

I have a different question about a different proposed building. Let's say I had 240V @ 20A available to me of solid POCO power from a neighboring source and I have a house that will consume 10kWH per day. Could solar panels be eliminated, and a battery bank power this hypothetical house and be recharged/maintained by the 20A 240V circuit?

Sure. The feature you want is called "generator support" and usually used to help out an undersized generator. You'll need a small battery bank, and it will tend to last longer than your average off-grid battery because you will always recharge fairly quickly (as long as your average load stays below 4.8kW.) The Outback Radian will do this, for example.

[Living Large]

I am glad to see more responses. I see that I did in fact jump out of solar system mode when I mentioned shop tools. When I was considering a solar house, I was not planning any of that. I don't want to to give the wrong impression that I would be building cabinets as a hobby, but on the other hand occasional use would be nice. I admit that the thought of even a single branch circuit got me all excited, but obviously it could be overloaded very easily - especially since it will be a few hundred feet long(!) I probably need to back off to the solar mindset in terms of usage - since the thought was I might replace solar panels with the branch circuit. The one comment about gen support - yes that is what I learned here and that would make sense for running tools occasionally. The fellow with the electric range as I recall - Chris? Amazing video of what he does with gen support. Thank you for your input.

[inetdog]

ChrisOlson if you are searching. No longer active, but some very good posts in the past.