I will use my own off-filigree battery bank for this example how to calculate its total Amp hours and Watt hours.

I'm not going to get into the little details and caveats. Simply this will provide a quick overview to figure it out. Maybe it will provide some insight for your own alternative energy battery bank one day.

Okay, lets go…

My objective was to put together a 48 volt battery bank (this is DC volts nosotros're talking about) with enough Watt hours (kWh – kilowatt hours) of energy storage to at least operate my essential systems for a few days before requiring recharge. I utilize an approximate 4000 watt solar console assortment to recharge past fashion of a charge controller followed by a DC > Ac inverter arrangement.

Why 48 volts? Because information technology's more efficient (than say, 12 volts), less loss, less electric current, and nigh off-grid inverters like to chew on 48 volts…

And so, there are all sorts of bombardment types and voltage configurations. I'm non going to get into all that. Instead, I'm going to use 12-volt batteries in this example because that's what I used on this particular battery bank.

My batteries are 12 volts each and rated for 100 Ah each (amp hours). What nearly the Amp hour rating? Put simply, you might say that this battery (if drained downward to 'dead') volition provide 1 amp for 100 hours. Or twenty amps for 5 hours. Depends how you expect at it… You get the moving-picture show?

(Well, technically a fully charged 12-volt battery while at rest, no load, would exist 12.7 volts. But I'thousand not getting into that sort of detail with this general principle.)

[ Read: Battery Country of Accuse ]

Volts times Amps equals Watts. And then this one battery will provide 12 x 100 = 1200 Watt hours. Or 1.2 kWh (kilowatt hours) of energy.

To get to 48 volts, I strung (connected) four batteries in series. So that string provides 48 x 100 = 4800 or iv.8 kWh of energy.

I put together 6 strings of 4 batteries in series. So I wired all six of those strings in parallel with each other. So that fabricated 6 x 4800 = 28800 or 28.8 kWh of stored energy.

I sketched out a uncomplicated block diagram to illustrate my battery banking concern:

These are lead acid type batteries. Although more specifically they are AGM (Absorbent (or Absorbed) Glass Mat (or Material)) so I can keep them indoors without off-gassing.

All batteries have a bike life versus depth-of-belch curve. The deeper yous regularly discharge them, the sooner they'll die off. These parameters vary quite a bit depending on the specific battery type / chemistry which I won't get into hither. Only I just wanted you to know that.

Given my specific battery type, I avoid discharging them further than 30% off the meridian (30% DOD or depth of belch). This greatly helps with overall cycle life of the battery banking concern in my instance.

And so that means I will try not to employ more than than thirty% of 28.viii kWh, or, nigh 9 kWh of energy for my given battery bank before recharging.

That'due south enough to provide me with a few days of "juice" for my essentials, such every bit my furnace during winter (as well tied with my hot h2o), refrigerator, chest freezers, and well pump.

We have lots of cloudy winter days here, so it works out pretty good. During summertime I accept "tons" of energy, then I run my whole house (including air conditioners) on the system. Although the Air-conditioning's go off at night (power hogs).

Okay, that was just a quickie on figuring out bombardment bank Amp Hours and Watt Hours.

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