Solar
Solar Charge Controller Size Calculator
Calculate the minimum solar charge controller current and a suitable standard controller size for your solar array.
W
A
Add the short-circuit current (Isc) of parallel panel strings. Check the solar panel label or datasheet.
%
A 25% margin is used as a practical default. Always check the controller manufacturer’s maximum PV voltage, current and power limits.
Suggested Charge Controller
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Choose a controller rated at least this high, subject to the manufacturer’s PV input limits.
Calculated Minimum Current
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Estimated Charging Current
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How it is calculated:
For MPPT controllers, estimated output charging current =
solar array power ÷ battery-bank voltage.
The selected safety margin is then applied.
For PWM controllers, sizing is based on the solar array short-circuit current (Isc), with the selected safety margin applied.
Final controller selection must also verify maximum PV open-circuit voltage (Voc), PV input power and manufacturer limits.