Battery Charging Time Calculator

Calculate charging time based on battery capacity and charging current.

Input parameters

Calculation results

Please enter the parameters and click the Calculate button.

Calculation formula

t = (Q × (target SOC − starting SOC) / 100) / (I × η)

- t = Charging time (hours)
- Q = Battery capacity (mAh)
Starting SOC / target SOC = initial / desired charge level (%)
- I = Charging current (mA)
- n = charging efficiency

Note:Actual charging time is influenced by factors such as the battery management system (BMS), temperature, and charging curve; the figures above are estimates only.

Charging Stage Description

1. Trickle Charge

When the battery voltage is too low, the charger first performs a precharge with a very small current (approximately 0.01C) to prevent damage from deep discharge. This stage accounts for about 5-10% of the total charging time.

2. Constant Current (CC) Charging

Charge the battery rapidly with a constant current, typically set at 0.5C to 1C. This stage can bring the battery to 70-80% capacity, representing the fastest charging phase and accounting for approximately 40-50% of the total charging time.

3. Constant Voltage (CV) Charging

When the battery voltage approaches full charge, the charging mode switches to constant voltage, and the current gradually decreases to 0.01C. This stage ensures the battery is fully charged to 100%, accounting for approximately 40-50% of the total charging time.

Charging Efficiency Reference Table

Battery Type	Efficiency range	Recommended	Remarks
Lithium-ion battery	90-95%	92%	High efficiency, low heat generation.
Lithium iron phosphate (LiFePO4)	92-98%	95%	Highest efficiency
Lithium polymer (Li-Po)	90-95%	92%	Similar to lithium-ion batteries
Lead-acid battery	85-95%	90%	Requires float charging.
Nickel-metal hydride battery (NiMH)	80-90%	85%	Memory effect
Nickel-cadmium battery (NiCd)	75-85%	80%	Strong memory effect