# Ups

Does anyone else in North America think about using/finding a UPS that is 220-240VAC so you get longer run times for your devices?

Or am I alone?

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I am a bit confused. Lets say your sysyem draws 10 amps at 110 volts. VoltsĂ—Amps= watts. Therefore, you would draw 1100 watts. Using the same formula, if we change the voltage to 220, the amps would be cut in half. So 220Ă—5=watts. This comes out to 1100 watts as well.

What I am basically saying, is that for a given size battery in a UPS, it has a given amount of watts in capacity. In a scenario such as this, there is no difference in capacity, and therefore runtime.

EDIT: changed multiplication symbol.

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How does a UPS with double the voltage get you longer run time?

I was spending the past 30 minutes googling this stuffâ€¦

http://www.apc.com/shop/us/en/products/APC-Power-Saving-Back-UPS-Pro-1500/P-BR1500G

Both of those use the same 12V battery:

So how does the 230VAC give a longer run time?

@Cobra92fs is more or less on the right track. If you want more run time you want more battery capacity. Those are generally in Ah or amp hours. Increasing your voltage doesnt always mean increasing efficiencyâ€¦especially so when youâ€™re inverting dc to ac. The batteries could be in a 12, 24 or even 48v configuration. The capacity only changes when the number of batteries changes.

The main reason to use higher voltages in the battery configurations comes down to load, not run time. If you have a 12v configuration and want 300w out of it youll have 25 amps to push through your wiring and components. If you use a 24v configuration you only need wires capable of handling half the current capacity. Theres also C rating but thats a different animal.

If you want more capacity/run time you simply want more amp hours.

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