Solar panels in parallel

Diagram of solar panels connected in parallel

The diagram illustrates two solar panels that have been connected in parallel therfore the voltage is the same. To find out the power of our solar charge controller we need to calculate the current flowing in the circuits. Current is power (Watts) divided by volts (Volts) In this example  it’s 120 / 12 = 10 Amps. A charge conbtroller like the  Steca PR1515 will be just fine for this purpose. The PR1515 is a 15 Amp solar charge controller.

Connecting solar panels in parallel

The positive outputs of each panel are connected together and the negative outputs are also connected together. However this can be quite difficult because the cable is quite thick. Solar panel combiner boxes can be used to connect solar panels in parallel.

Solar panel connection box

Solar panel connection / combiner box

If the panels have the MC4 Style connectors  you can also use Y connectors.

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