Something to note ... as electricians we always calculate stuff at higher voltages ... like 230 or 400 or 660 ... 11KV etc

But when dealing with batteries ... inverters and stuff ... and its 2 am in the morning your brain is not thinking clear ... dont mix the voltage/current and power.

for example ... when looking at how long a battery will last.

Lets say your power is 1000 watts ... the voltage is 230 VAC and the current is 4.35 amps.

When you working out how long the battery will last ... make sure you work out the DC current

dont make the mistake of thinking 4.35 amps (@230 VAC) should last 20 hours on a 100 amp/hr battery

Actually the power is 1200 watts / the battery voltage ... lets say 48 VDC for this example = 25 amps

If you have 100 amp/hr capacity and lets say you are using flood lead acid batteries ... best you check the manufacturers spec.