How to Wire Solar Panels in Series Parallel

This video will teach you step by step how to wire your solar panel array in a series-parallel configuration.

Wiring solar panels in series-parallel is just a matter of connecting The positive and negative wires for neighboring solar panels together creating individual series wired solar panel strings; then wiring those series wired strings in parallel by connecting the positive and negative of each series string to a MC4 Combiner to the wire that goes to the charge controller.

For the example of todays video; I am going to be wiring 4 100w rich solar panels in series-parallel; right over here.

I’ve already used my multimeter to determine which wires are positive and which wires are negative and noted that with a bit of red heat shrink on the positive wires AND covered the panels with cardboard so I’m not working with live voltage.

First, I want to wire the outside pairs together in series. That means wiring the positive to the negative on these two panels. And wiring the positive to the negative on these two panels.

Now… I have two pairs of panels wired in series. Now; I need to wire these two series wired strings in parallel.

To do that, I’m going to take all of the positives from each series wired string of solar panels; and attach them to an MC4 combiner.

Next, I’m going to take ALL of the negatives from each series wired string of solar panels; and attach them to an mc4 combiner.

Then I can attach each of the positive and negative mc4 combiners to the wires that will go through the roof and connect to the charge controller.

If the array needed to have fuses, I would attach the MC4 fuses to the positive MC4 combiner between the combiner and the panel wires. Some arrays need fuses; some don’t. You can rely on my free wiring diagrams to show you when to use them or not, but we will be covering the ‘why’ in a future video; so consider subscribing.

If you have more than four panels, the theory is completely the same. If we had 6 solar panels, they could be wired in a 3 panels in series with the 2 series strings in parallel.

OR… They could be wired 2 panels in series with the 3 series strings wired in parallel.

More panels? Same concept:

16 panels. series strings of 4 panels with the four series strings wired in parallel.

Now, something to note. All series strings really need to be identical. So; 5 solar panels cannot be wired in series parallel BECAUSE it’s highly not recommended to have an array with a series string of 2 panels wired in parallel with a series string of 3 solar panels.

Now… why would we use series parallel? Series-parallel allows us to keep the voltage from our solar panel array high enough for the MPPT charge controller to effectively do it’s job but low enough to stay under max voltage rating of the charge controller.

It also allows us to keep the solar panel array amps low enough we can effectively use smaller wire throughout the entire array without worrying about excessive voltage drop; but we are going to talk about that in MUCH more detail… next week.

I hope you found this video helpful and if you did, it’d be awesome if you’d share it with somebody or a group who you think could benefit from it and leave the video a thumbs up. Drop any questions you’ve got in the comments section below. Subscribe if you want to see more DIY camper building tutorials and I will see you in the next video.