Log in
Article search:

Q & A

100 w solar panel wiring

I have brought 2 secondhand solar panels.
1 panel has a red and black cable exiting from each side of the junction box.4 wires.When I look on the Internet panels have 1 red cable and 1 black cable exiting from each side of the junction box.2 wires.
Internally in my junction box the black is wired to black and red to red. I am looking to how to wire them up correctly for my narrowboat. Appreciate some help many thks Kevin.

Asked by: Kevan  | 4.25pm, Sunday 31 December


WW says:

Firstly, check the voltage of the panels; if they are not labelled, place them in sunlight and measure the voltage between the positive red and negative black wires with a multi-meter, a reading between 12 and 18V volts indicates a nominal 12V panel.
Assuming that your boat is 12V and the panels are 12V, you now have two options:
You can connect both panels in parallel; connect the red wires together, the black wires together and connect them to the respective connections on your battery. If the maximum panel output is not more than 10% of the battery capacity, a regulator isn't generally required for lead acid batteries.
If you do need a regulator it would maximise the solar power by connecting the panels in series and connecting them to the battery via a MPPT solar controller. This will give a higher overall output as it works longer in low light.
It is important to fuse the connection to the battery to make a safe system (this is a BSS requirement).

Rupert Smedley  | 2.51PM, Wednesday 3 January

You must log in to post an answer.