Best way to wire solar panels on Bus / Motorhome / Van
A guide to wiring solar panels on top of your motorhome.
Series Vs Parallel Vs Series and Parallel.
First of all we need to explain a few things,
Series is when the negative and positive leads are connected together leaving just a positive at one end of the array and a negative at the other. Like this,
The benefit of wiring panels in series is that the Volts increase (not the Amps), When the volts increase and not the amps it means smaller cable size and better for running long(er) distances
Parallel is when all the positives join together and all the negatives joins together. Like this
The benefit of adding them in parallel is that it keeps the voltage the same as the panel voltage, but the downside is that increases the Amps. Higher amps means bigger cable and not ideal for long distances.
So after saying that, my favourite way of wiring solar panels is a combination of the 2 and wiring them in Series / Parallel like this
The reason I like it this way is that when using household solar panels that are 40 Volts, wiring them 2 in series doubles that to 80 Volts and then by paralleling that with another 2 panels keeps those volts at 80 Volts and increases the Amps.
This is perfect for wiring banks of 4 solar panels and even 6 solar panels (3 in series, 2 in parallel).
On the roof of Sonny (Our Bus) we have 7 solar panels. They are split into 2 groups. 1 Group of 3 Solar Panels in Series and 1 group of 4 Panels that are 2 Series 2 Parallel.
Hope this has helped with answering some questions you may have around wiring solar panels. If you have a project and unsure on things, feel free to book a call here and we are more then happy to help you out!
1 comment
Thanks for all the resources and info on your site. It’s great.
I am wondering why so many professional 12v installations use “small” solar panels (like 200w and under) when there are larger house panels (500w +) available? You so often hear of people complaining about roof space yet say 2x 500w panels will surely take up less space than 5x 200w panels? Are larger house panels not recommended?