Battery Capacity, Runtime and Charging

These tools cover how much energy a battery holds and how long it lasts. Convert amp hours or mAh to watt-hours, find runtime and charging time, read state of charge from voltage and size an inverter for your appliances.

Tools in this group

• Amp Hour Calculator (Ah to Wh) — Convert amp hours to watt-hours and back, find the Ah a load uses, or add up a series and parallel battery bank.
• Battery Charging Time Calculator — Enter the battery capacity, how full it is and the charger current to estimate the charging time.
• Battery Runtime Calculator — Enter the battery capacity and the load to see how many hours it will run, for lead-acid, AGM, lithium or UPS batteries.
• 12V Car Battery Voltage Chart (State of Charge) — Read a battery's state of charge from its resting voltage, or see the full chart for 6, 12, 24 or 48 V, using each battery maker's own table.
• Inverter Size Calculator — List the appliances you will run to get the inverter size in watts, the surge it must handle and the battery current.
• Converter: mAh to Wh (and Wh to mAh) — Enter the battery capacity in mAh and its voltage to get watt-hours, or convert Wh back to mAh.
• Solar Charge Time Calculator — Enter the battery capacity, the charge range, the panel watts and your sun hours to see how long the panel needs.