Usage or Capability of Inverter

[max2k]

At 1380ah you will want at least C/13, or 106 amps, charging current. That's about 1500 watts of panels. However I would avoid the smaller 100 watt panels and use the cheaper 200-300 watt panels. Your charge controller will be able to handle the higher voltages of the larger panels.

I look at this slightly differently: all that extra capacity is for 5 days autonomy, he'd need to charge batteries once even if it would take few days and then he'd need PV to compensate for his 3.3kWh daily consumption + some inefficiencies.

If his consumption stays flat through the winter as well he would need 3.3kWh / 0.9 efficiency / 2.5hr in winter = 1.5kw array. 1.5kW array at 12V would produce 125A charging current. Close enough to your estimate .

OP, if you want to increase your battery size you can do it by connecting new ones in series- like if you connect 2 more banks like you have now in series you'd get 36V system which in turn would drop currents by factor of 3: 1.5kW / 36V = 42A so SK won't be laughing that much

[max2k]

Make sure your life, medical, health, and home owners insurance policies are paid up. You going to need them to bury the dead and rebuild your home from the pile of ashes.

come on, you can make short runs of 400A conductors out of multiple big cable shielding pieces to remain flexible and have some multiple contact lugs on each to spread the current / reduce contact resistance- that's why I asked to look at the pics of the setup, he must have come up with some ingenious solution for that. Short of that and this whole thing is out of window. OP is also down to 2kW inverter now.

[Sunking]

OP is also down to 2kW inverter now.

Still 4 times to large for 12 volts. 2000 watts is 48 volt battery territory with a minimum 400 AH.Not to mention a waste of money when al that is required is 6 AWG wire.

[Mike90250]

Since Sunking didn't say it, I will:
Ya gotta get yer head out of the 12V box. 125A charging current should be your 2nd tip-off something is wrong, That's 2, $600 charge controllers. And the fat chunks of copper wire with a $5 lug on each end for the interconnects...

This is a 48V battery bank application. Same amount of lead, but you use voltage to your advantage, like the big boys do.

[max2k]

Still 4 times to large for 12 volts. 2000 watts is 48 volt battery territory with a minimum 400 AH.Not to mention a waste of money when al that is required is 6 AWG wire.

who knows- he could lay them out as some super computer with batteries located vertically, charge controller on one side and inverter on the other with huge copper/silver buss bars going vertically as well. With required cross section those buss bars could actually serve as construction elements as they could probably provide necessary mechanical support. At 12V isolation would be trivial. I'm dying for pics now .

[jjrr007]

I have contacted a solar tech guy.

I told him about my situation. He recommended the following:

1.Increasing my battery by 4 more batteries to 24 volts with 460ah

2. total of 1,000 watt panels. My existing panels don't appear to be providing the proper amperage. so he suggested to test the amperage by connecting each one in parallel one at a time to see if the amperage goes up, what the problem is or if another brand of panels is needed.

3. keeping the existing charge controller. The charge controller can handle 1,800 watts with a 24 volt battery

4. Change my inverter to a 24 volt model.

Is there any work around to doing number 4? Maybe a device I can put in the middle?

[jflorey2]

]Is there any work around to doing number 4? Maybe a device I can put in the middle?

Sure, you could get a boost converter. Five QSB40024S28 boost converters would do it and get you 12 to 24V at 2000 watts. They run around $260 ea for a total of $1300.

[jjrr007]

Do you guys/gals think that my plan in my previous post seems OK for a 100 kilowatt per month usage system (1 small window ac unit or sump cooler, flood lights that use 60 watts total, 1 camera system, couple of laptops)?

If I should post the plan on another thread, feel free to let me know.

Thanks again!

[bcroe]

100 kilowatt per month

Do you mean "100 kilowatt HOURS per month", because that made no sense? BRUCE ROE

[KMac]

Yes, I think your solar pro seems about right, depending on the size of window air, and if it is a place you will live, versus a weekend cabin.

I have a 24v system, 1000w of panels 4x250w), 60 amp controller, 315 amp hour 6v Trojan batteries (20 hour rate), and a 2000 w inverter, and it runs my 5,000 BTU A/C by GE from Walmart, and keeps my 200 square foot well insulated cabin nice and cool. I am in the Midwest and get about 5 hours sun in summer, best case, and have panels tilted to summer angle. Will get about 750-850 watts from them max on a clear day, but over 4-5 hours it is sufficient. Lights (LED), computer, phone charger and the like are relatively insignificant. Water pumping and AC are the big draws. I keep the morning cool air and start AC early on "Eco" mode, so it seldom runs full speed (which is about 450 watts. I also run a 1/2 hp water pump on my well an hour or so throughout the day to water plants (220v grundfos that draws 850 w, and has little to no surge draw).

Ultimately, you need to learn your system capabilities in terms of production, and cost of loads you run. Then adjust accordingly., I don't live there so usually it's just a couple or three days in a row I am there, and only the water pump runs daily regardless. If you need to live there and have 3-5 days capability with no sun, then plan a bigger system.

Get into float almost every day with good weather.

Would not do it at 12v for a host of reasons.

Good luck.