Math question...

[RStephen]

My HVAC blower uses 4.689 kwh in a 24 hour period (based on a watt meter) with a cost of .12 per kwh for a total of .56 cents per day. If I have a lifepo4 100ah battery on this load, how long will the battery last? Not sure how the math works and am trying to get a handle on it.
Thanks!

[PNPmacnab]

That battery only has about 1KWH of usable energy in it. A little over 5 hours.

[Ampster]

If that is a 12volt battery 100 Amps times 12 Volts equals 1200 Watts. Or as PNPmacnab said, about 1kWh of useable energy.

[SunEagle]

I think if you do the math you will find batteries will be closer to $0.50/kwh which is 4 times what the POCO is charging you.

[azdave]

I think if you do the math you will find batteries will be closer to $0.50/kwh which is 4 times what the POCO is charging you.

I thought that too but he's posting in the "Off Grid" section so there may not be a POCO to deal with.

[SunEagle]

I thought that too but he's posting in the "Off Grid" section so there may not be a POCO to deal with.

Good point but why mention the 12 cents/kWh unless there is a POCO involved.

It is possible the OP wants to go off grid but they will be spending a lot of money and time doing it.

[J.P.M.]

I thought that too but he's posting in the "Off Grid" section so there may not be a POCO to deal with.

$0.12/kWh sure sounds like a POCO rate.

Also, FWIW, the blower probably doesn't operate constantly.

[sdold]

At my Northern CA PG&E bottom tier rate of $.32 or $.34/kWh, it's still not worth going off grid with the ongoing battery expense, but if I was only paying $.12/kWh I wouldn't even consider batteries. To me that's almost free energy. Even my DIY grid tied system only brought me down to effectively $.05/kWh over the expected life of the system.