How to run 2000w panels during daytime - on two 12v batteries

[SoFar]

I have 6 panels that are 310W (VOC 40.1V and ISC 9.76A).
I also have two 12V 80Ah Lead acid batteries that i plan to connect in series and make a 24V.
I figure i will be using about 1200 watts of so of power.


I live in South Florida and ONLY plan to use these "DURING DAYTIME / DAYLIGHT" if the power goes off.

Will this work? I don't intend to purchase any more batteries, however, I will need to buy an inverter.

The question is, if it's mostly sunny, will I be able to run about 1200 watts of power with the two batteries i have?

Thanks

 

[MichaelK]

No, this will not work well as intended. All six panels will fry your battery with far to many amps. Lead-acid batteries like charging at about 1/8th of their capacity, so 80Ah X 1/8C = 10A. With a 24V battery, expect bulk charging to be at ~25-26V, with also the expectation that your panels will only put out 85% of rated current. So, the math is (25V X 10A)/0.85 = 294W, or basically just one of your panels. That math assumes you are utilizing a MPPT charge controller.

Likewise, a battery does not like being drained at more than 1/8th of C, so that's 10A at ~25V, or 250W. If you want to run 1200W, then you really should have a (1200W/24V) X 8C =400Ah battery. This 400Ah battery would like being charged at ~50A. For a 24V battery, that's (50A X 25V)/0.85 = 1470W of panels. Four of those panels in series would be fine.

Large loads with a small battery will send ripple current back into the inverter, gradually degrading it. Connecting this small battery will work at first, but the moment a cloud floats in front of the sun, a large load is going to drain this battery very fast.

Final answer: Too many panels with too little battery.

 

[OnGrid]

1) I thought that a "good" MPPT controller would handle this?

2) If not, what if I had an "all-in-one" (IE LV2424) with the two batteries?

 

[Bud Martin]

So what charge controller do you have right now?
Right now you will have 24V 40Ah Lead acid battery bank.

 

[OnGrid]

So what charge controller do you have right now?
Right now you will have 24V 40Ah Lead acid battery bank.

I did not purchase one yet.

I was thinking about getting the Victron.

I only have the two batteries and the panels.

 

[sunshine]

You seem to be seeking similar to what I have now except mine is 12v and 2200w pv
Your 24v should work just as well and with more panels even better although staying with 12v has certainly made it easier to diy.

The question is, if it's mostly sunny, will I be able to run about 1200 watts of power with the two batteries i have?

My fla batteries were old when installed. Battery capacity is inconsequential. But be aware of gassing by overcharging.
To compensate when the sun goes out there is 240v ac / 1500w DC PSU set @ 12.6v ,

117.0US $ 10% OFF|S-1500w Switching Power Supply,voltage And Current Adjustable Ac Dc Power Supply Transformer Dc12v 13.8v 24v 27v 36v 48v 60v 72v - Switching Power Supply - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

connected through diodes.

There is also a super capacitor

38.63US $ 20% OFF|Super Farad Capacitor 16v 83f 6pcs 2.7v 500f Flat Angle Electrolytic Capacitor With Protection Board Single Row Ultracapacitor - Filters - AliExpress

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

Which, in spite of reservations, worked really well with the earlier low powered psu and really flattens out the voltage spikes now.
Not sure if you can series these for 24V?

Everything I do is with the intention of eventually going to LiFePO4