What kind of batteries do I need to power a 1000 W, 220V appliances for up yo 10 hour

[dtm33]

What kind of batteries do I need to power a 1000 W, 220V appliances for up yo 10 hours a day?

I will be using the grid to charge the batteries .
please help.

 

[Optimistic Paranoid]

1000 watts divided by 220 volts equals 4.54 amps. So you would use 4.54 amp hours every hour it was on, or 45.4 amp hours over 10 hours.

Of course, you will need an inverter to change 12 volts dc to 220 volts ac, and there will be some losses there. The best inverters are about 90% efficient, so figure 5 amps an hour and 50 to 60 amp hours over 10 hours.

You didn't say exactly what the appliance is, but be aware that if there is a motor in it, it will need a heavy starting current to overcome the inertia and get it spinning before it settles down to it's average running current. Typically, starting current can be 4 or 5 times the running current, so you will need to size your inverter with that in mind - you might need a 2 or even a 3 thousand watt inverter to run your 1000 watt device. Be aware that 220 volt inverters of that size are not cheap. Also be aware that you will need a large and probably expensive battery charger to recharge the batteries every day.

Anyway, assuming you are not running anything else off of them, a pair of 6 volt golf cart batteries, wired in series to provide 12 volts, should do you just fine. They will give you 200 to 220 amp hours. Since you should never discharge batteries by more than 50 % for longest life, that will give you 100 to 110 USABLE amp hours in your battery bank.

Regards
John

 

[blars]

Optimistic Paranoid shows the confusion using amp-hours rather than watt-hours, and undersizes the battery by a factor of almost 20. 1kW at 12v is over 83 amps, assuming no loss in conversion. So expect to use about 1000 amps-hours at 12v, so for lead-acid you need at least 2000 amp-hours. 20 golf cart batteries should do it. With LiFePO4, 1200 amp-hours would be enough. (Smaller, lighter, longer lasting, and more expensive up front.)

 

[Optimistic Paranoid]

Yup. That's what I get for trying to do math problems when I'm half asleep.

My initial reaction to the post was " Can't be done". Then I (mis)did the math, and was surprised at how apparently do-able it was. That should have set off alarm bells in my head.

Good catch, Blars.

Regards
John

. . . there goes my reputation for infallability (grin).

 

[highdesertranger]

I am curious. what do you want to run that takes 1,000 watts at 220v for 10hrs? my guess would be an ac. I would be looking for other options. you said you will be recharging off the grid, why not just run it off the grid? highdesertranger

 

[TucsonAZ]

Yeah, you will need a big bank of batteries, 10kwh drain means a 425ah battery bank at 48v which by the way would be the only even remotely sensible choice in terms of inverters, I would go higher than a 48v inverter for that matter if you can do so. Do not even think about using a 12v (or 24v) inverter for something like that.

 

[PastTense]

OP, tell us exactly what you need to do and we can provide better advice.

I am thinking you need to get a generator instead of rely on batteries.