When connecting multiple solar panels in a 12-48 volt off-grid system, you have a few options: parallel, series, or a combination of the two. In this article, we’ll give you the basics on wiring solar panels in parallel and in series. Let’s start off with a quick comparison of parallel circuits and series circuits.

Parallel circuits have multiple paths for the current to move along. If an item in the circuit is broken, current will continue to move along the other paths, while ignoring the broken one. This type of circuit is used for most household electrical wiring. For example: when you turn off your TV, it doesn’t also turn off your lights.

When wiring solar panels in parallel, the amperage (current) is additive, but the voltage remains the same. eg. If you had 4 solar panels in parallel and each was rated at 12 volts and 5 amps, the entire array would be 12 volts and 20 amps.

Series circuits have only one path for current to travel along. Therefore, all the current in the circuit must flow through all the loads. A series circuit is a continuous, closed loop – breaking the circuit at any point stops the entire series from operating. An example of a series circuit is a string of old Christmas lights – if one bulb breaks, the whole string turns off.

When wiring solar panels in a series, the voltage is additive, but the amperage remains the same. eg. If you had 4 solar panels in a series and each was rated at 12 volts and 5 amps, the entire array would be 48 volts and 5 amps.

Remember: just like batteries, solar panels have a negative terminal ( – ) and a positive terminal ( + ). Current flows from the negative terminal through a load (current consumed by a piece of equipment) to the positive terminal.

Wiring Solar Panels in a Series Circuit

Connect the positive terminal of the first solar panel to the negative terminal of the next one.

eg. If you had 4 solar panels in a series and each was rated at 12 volts and 5 amps, the entire array would be 48 volts at 5 amps.

Wiring Solar Panels in a Parallel Circuit

Connect all the positive terminals of all the solar panels together, and all the negative terminals of all the panels together.

eg. If you had 4 solar panels in parallel and each was rated at 12 volts and 5 amps, the entire array would be 12 volts at 20 amps.