Home > Technology > How to Calculate the Recharge Time for a Lithium Ion Battery

How to Calculate the Recharge Time for a Lithium Ion Battery

Published At : 16 June 2018 00:00

Regardless of voltage, the recharge time of a li-ion battery is determined by the constant current level applied by the charger, measured in milliampere-hours (mAh). Because of the inherent difficulty in evaluating the precise remaining capacity of a lithium ion battery prior to recharging, the standard convention is to calculate the maximum recharge time: the time it would take to recharge a near-fully depleted cell.

For example: my battery capacity is 50 Ah

1. Determine the charger's standard recharging current level, in mAh. This information is typically printed on the back side of the charger itself. If not, the current level can be found in the Owner's Manual under "Specifications".

2. Divide the current level from Step 1 by 1000 to convert its units from mAh to Ah.

3. Divide 50 Ah by the current level from Step 2. This will give you the ideal maximum charging time for the battery, in hours.

4. Multiply the result from Step 3 by 1.15. This factor adjusts for the average inefficiency of the charging process. The result is the estimated maximum real charging time for the battery.