Battery inverter calculation

[sponge]

Just curious and trying to get hang of solar and inverters, if you measure /calculate on the ac side of the inverter say 1000 watt being used it is about 4.55amp, but if you do it at the dc side where there are say 24 volt it is 41.67 amps, so therefore a set of series batteries of 12 volt would only last about an hour if you calculate at the dc side, but longer if you do it on the ac side, so where is the right side to calculate how long a battery pack will last?
Thanks

 

[johnb2713]

You say a series of 12v batteries would only last half an hour, that depends on the capacity, if they were 500a/h for example they would last a lot longer than 30 minutes. The other thing to throw in the mix is the efficiency of the inverter and the battery system, there will be losses, typically inverters are between 75% and 95% efficient dependent on make, model and price paid.