Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Capacity (Ah)

Rated capacity of the battery.

C-rate

Charge rate as a multiple of capacity; typical gentle charging is half the capacity per hour.

Compute a safe constant-current charge rate for a battery from its capacity and a C-rate multiple. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Charge current (A)

Recommended constant charging current.

• Battery capacity, state of charge, runtime, and aging depend on chemistry, temperature, discharge profile, cutoff voltage, cell balance, charge method, rate capability, self-discharge, and prior history. Nominal amp-hour or watt-hour ratings do not guarantee usable energy under every load.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Charging Time Hours

  Estimate the hours needed to fully charge a battery at a constant current, including a documented 1.2 inefficiency factor that accounts for taper and losses.

• Battery Life Calculator

  Estimate battery runtime from rated charge capacity and constant load current: hours = mAh / mA. Real-world derating (Peukert effect, temperature, cutoff voltage) is not modeled.

• Discharge Depth Percent

  Compute the depth of discharge of a battery from the charge drawn and its rated capacity.