I have an AC system which has a continuous load of 7 amps at 120 volts. To run this system, I need a set of AGM battery and an Inverter system (power factor- 0.8). The inverter is 24 volts and rated for 2 Kva. I have a few 12 volt, 200 AH batteries.
Now, how do I calculate the run time of my battery at full load mentioned above for the following situations ?
a.) Two 24V, 200 AH batteries.
b.) Two 24V, 400 AH batteries.
Also, from the battery manufacturer, I know that the cycles available for the battery are 1200-1300 for 30% DOD and around 600 for 50% DOD for each 12volt, 200AH battery. Now, will I get more cycles if I connect two 12V, 200ah batteries in series/parallel (More than 1200-1300 or 600 cycles ?) for the entire battery system, or even more cycles if I connect four 12V, 200AH batteries in series/parallel or a combination of series and parallel for the entire battery system?
Best Answer
There are really two questions here.
((120V / 24V) * 7A) / 0.85= 41A. This number is a bit on the high side since the voltage will initially start around 26V and drop down as you discharge the battery. The run time for 50% discharge is then calculate as a) (200 AH/41A) / 50% = 9.7 hrs. In case b) you have double the capacity so the runtime is increased by two.