C-rate

Definition

C-rate is current relative to rated capacity. 1C on a 100 Ah battery is 100 A; 0.5C is 50 A. Maximum continuous current is C-rate × Ah. Load C-rate is load amps ÷ capacity (load amps themselves come from I = P ÷ V). High inverter, trolling-motor or surge loads can exceed a cheap BMS even when the watt-hour math looks fine. Always use the continuous rating from the BMS or cell datasheet, not a peak burst figure.

Calculators that use this

• battery storage

  Battery C-Rating & Max Discharge Calculator

  Convert a battery C-rate into maximum continuous amps and watts, and see how hard a given load is on the pack.

• battery storage

  Trolling Motor Battery Calculator

  Estimate trolling-motor amp draw from thrust and voltage, then see runtime from a 12V, 24V or 36V battery bank.

• inverters

  Inverter Sizing Calculator

  Size a pure sine inverter from continuous watts, motor surge and inverter efficiency with 25% headroom.