Charge rate

Charge rate describes how quickly a battery is being charged compared with its usable capacity. It is usually expressed as a C-rate, or inferred from a charging-power limit in kW or a charge-current limit in amps. A 0.5C charge rate means the battery is charging at about half its capacity per hour, so a 10 kWh battery charging at 5 kW is roughly at 0.5C before losses and manufacturer limits. Home battery documents may state the practical limit as maximum charge power, maximum charge current or a control-app charging limit rather than a printed C-rate. The figure should be read with the battery capacity, inverter limit and manufacturer conditions because a system may charge more slowly near full, outside ideal conditions or when its controls restrict charging.