Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency)
- Battery capacity: 100Ah
- Charging current: 12A
- Battery type: Sealed Lead acid
- Battery DoD (depth of discharge): 75%
- Charge efficiency: 85% SLA - 95% Li
Example:
(100Ah × 25%) ÷ (12A × 85%) = 75Ah ÷ 10.2 = 7.35 hrs
100 x 25% = 75
12 x 85% = 10.2
75 ÷ 10.2 = 7.35 hours
This is an estimated charge time calculator. Many factors and affect charge times including:
- Your battery may be powering something. Charging times will be increase as power is being used
- Battery chargers aren't always outputting their max charge rate.
- Batteries lose capacity as they age. An older battery will have less capacity than an identical new battery.
- Lithium batteries have a Battery Management System (BMS). BMS can adjust the charging current to protect the battery and optimize its lifespan.
- Lead acid battery chargers usually have a timed absorption stage. After being charged to around 70-80%, many lead acid battery chargers enter absorption mode. (ABS code on our 1000w/2000w inverters) This is usually a fixed time to protect the health of the battery. Typically 1-2 hours.