Battery Size Calculator
System Voltage =
Connected Load = 0
Load Rating =
Parallel Batteries = 1
Battery Life Needed
Calculates the size of batteries required to carry a given load over a specified period of time.
- System Voltage: Voltage of the electrical system. Be sure to enter the actual voltage of the system and not the battery if the batteries will be connected in series. Batteries connected in series will see the system voltage increase for each battery connected but the battery capacity will stay the same. For example: If 2- 12 volt, 1 amp-hour batteries are connected in series, the system voltage would be 24 volts and the batteries would be able to power a 1 amp load for 1 hour.
- Connected Load: Select whether the load rating will be entered in watts or amps.
- Load Rating: Enter the total rating of the load to be served. For example: If the batteries were supplying 6- 15 watt landscape lights, the total load would be 90 watts.
- Parallel Batteries: Enter the number of batteries connected in parallel. If only 1 battery is to be used, enter 1. Batteries connected in parallel will see the capacity of the batteries increase for each battery connected in parallel but the voltage will stay the same. For example, if 2- 12 volt, 1 amp-hour batteries are connected in parallel, the batteries would be able to power a 1 amp load for 2 hours and the system voltage would be 12 volts.
Battery Life Needed
Battery Life Needed: Enter the time that the batteries must power the load before a full recharge. The time can be entered in hours and minutes.
- Amp-Hours: Number of amp-hours needed for this application.
Batteries are sized in amp-hours. A 2 amp-hour battery will power a 2 amp load for 1 hour or a 1 amp load for 2 hours. Input the system voltage, the connected load, the number of batteries connected in parallel, and the time required for the batteries to last before recharging to calculate the minimum battery size in amp-hours.
What is the battery size required for a 24 volt battery with a 2 amp load rating and 1 parallel battery?
- System Voltage: 24
- Connected Load: Amps
- Load Rating: 2
- Parallel Batteries: 1
- Hours: 12
- Minutes: 30
The battery size is 25 amp-hours.