John Pearson wrote:

> I want to run a 850 watt AC motor for 10 seconds off 12 volt batteries.

What VOLTAGE AC?

> How many 12 volt batteries and what AH would they need to be. I calculate 6.5 batteries (80 volts)?, but the AH part has me puzzeled.
>

You should be considering an INVERTER.
(I hope you don't believe you can power an AC moter from 80 volts DC....)
Double the load power as the battery supply, 50% efficency.
1,700 watts at 12 volts is 142 amps. (Like starting your car!)

142 amps for 10/3600 hour is .4 amp hour.
BUT, you will NOT be able to demand 142 amps from a tiny battery.

>
> Thanks for any help
>
> John
>
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