Altenergyweb Battery Array Estimator
Daily AC load (watt-hours)
Inverter efficiency (%)
Daily DC supplementary load (watt-hours)
Overall DC system voltage (volts)
Expected number of consecutive no sun days (#)
Maximum acceptable battery draw down (%)
Single Battery capacity (amp-hours)
Single battery voltage (volts)

Number of batteries in series
Number of batteries in parallel
Total Number of batteries needed
This array's max. allowable bulk charge current (25% of C/20 amp-hours)
This array's recommended absorption charge current (2% of amp-hours)
This array's max. recommended bulk charge current (1% of amp-hours)
To estimate the number of batteries you need for photovoltaic installation, enter numbers for the size of your loads, the capacity of the batteries you have chosen, the individual battery and system voltages, maximum acceptable discharge, or the percentage you will allow the batteries to drop. The calculator responds by giving the number of batteries needed in the array. At any time, change the input values. The calculator recomputes when you click outside a box.