Solar panel fuse question

[Machinetools1]

Okay.... So I have a 2019 Thor 29m Windsport motorhome. I put a 40 amp Renogy MPPT controller and 4 100 watt panels on the roof.

The motorhome is wired for solar but am not sure if I need to places fuses between the solar panels and the controller. I am planning on wiring the solar panels in series as I am not sure if the wires are big enough to run the panels in parallel.

So my question is how many fuses to I need, where to place them and what size.

[Chateau_Nomad]

Your answer can be found here:
https://www.renogy.com/blog/how-to-f...-solar-system/

[taylorbob1]

Here’s a couple of photos that may help you.
Both in Series and in parallel…

[DavidEM]

As long as the wire gauge from the panels to the controller is big enough to handle the maximum current the panels can put out, there is no need for a fuse. The spec for the maximum amperage a panel can produce is Isc which is 7 amps for a 100 watt panel.

If you wire them all in series the voltage could be high enough to be dangerous: 4 times Voc or 4x21=84 volts. I would wire them in series/parallel which gives a maximum voltage of 42 and a maximum current of about 14 amps.

12 or 14 gauge works fine for wiring up the panels and the 10 gauge wire that is typically run from the solar port to the controller on solar prewires can handle 14 amps with minimal voltage drop.

[Machinetools1]

How would you wire in series/ parallel with 4 pannels?

[taylorbob1]

Here’s a photo example of a 4 panel array wired in Series & Parallel at the same time…

[Machinetools1]

Thank you very much for the replies. I think I am going to go with the series/parallel hook up.