C-rate calculator

Turn a power into a C-rate on nominal and usable kWh, then find which limit sets the power in a battery and inverter pairing.

Read this first. The defaults reproduce the page example: Pylontech US5000 datasheet figures and a Sunsynk 5 kW inverter's printed limits, in a hypothetical pairing. They are not a compatibility claim. Power is taken as amps times nominal voltage, with no losses or voltage sag. Parallel current limits are assumed to add. Use a dot for decimals; "10,000" is read as ten thousand.

1. C-rate from a power

Nominal energy (kWh) Usable energy (kWh, 0 to skip) Nominal voltage (V) Charge or discharge power (kW)

Result	Value
Capacity in amp-hours at this voltage (nominal kWh ÷ volts)	-
Current at that power (kW ÷ volts)	-
C-rate on nominal energy	-
C-rate on usable energy	-
Hours to deliver the usable energy at this power	-

2. Which limit sets the power?

Modules in parallel (whole number) Module nominal energy (kWh) Module usable energy (kWh) Module nominal voltage (V) Battery current limit per module (A) Inverter DC current limit (A) Inverter AC rating (kW)

Result	Value
Battery limit (modules × amps × volts)	-
Inverter DC limit (amps × volts)	-
Inverter AC rating	-
Lowest limit, and what sets it	-
C-rate at that power, nominal and usable	-
Hours to deliver the usable energy	-

Method: C-rate = power ÷ energy, which equals amps ÷ amp-hours only while voltage stays at the nominal value. Power limit = the lowest of modules × amps × volts, inverter amps × volts, and the inverter AC rating. Which current figure to use (recommended or maximum) is the maker's choice to confirm.