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Solar Regulator Sizing Calculator

This calculator will help you understand the factors involved in sizing a solar regulator for an off-grid battery charging system. Before you start you will need to know

  • the running voltage of the battery 12Volt or 24Volts
  • the rated power of your solar panels and any drawing load on the battery
  • whether you intend to connect your drawing load direct to the battery or through the regulator, see below for connection options

Solar Regulator setup options

The advantage of a direct connection is that the regulator need only be sized to the rated solar panel power. The advantage of connecting the load through the regulator is that the regulator will protect the battery by preventing deep discharge - the disadvantage is that the regulator must be sized to handle the maximum power draw on the battery.

† Note, certain atmospheric conditions, such as cool sunny conditions with scattered light from nearby objects and from nearby cloud can increase your solar panels output by as much as 30% above its rating. Furthermore, a regulator should be selected so that it is not operating at near peak capacity, hence the calculator will include an amperage buffer. You may also consider solar panel additions in the future.

‡ The drawing load on the battery can be connected through the regulator or direct to the battery.

You can also size your solar panels using our off-grid solar panel sizing calculator. You can also size your solar regulator wiring using our solar wire sizing calculator.

Disclaimer: This free to use calculator is provided as is. While we have endeavoured to make this calculator as accurate as possible we take no responsibility for accuracy of the assumptions, data or advice it provides. This calculator should be cross checked with other information and should not be used as the sole means in making your purchasing decisions.