I also installed a solar charge controller inside the boat.
Fuse individual solar panels or array.
Some panels have bypass diodes whose function is to bypass shaded sections of panels but you loose about 8 volts each time they kick in and your array wattage drops.
Now in the case of 3 panels in series and 4 strings in parallel if one string shorts the max amperage to short is 39 12 which exceeds the 30 amp max current rating of the 10 awg wire.
I assume this is so if a panel shorts internally the other panels don t pump all their current through said short and cause overheating.
This means each series needs a fuse breaker placed in the combiner box as shown here.
There are many fuse wire gauge tables on the web.
My question is about providing a fuse or circuit breaker for the output of the panels.
In a parallel system a combiner box is used that holds the fuses breakers to each panel plus one or more combined fuse leading to the charge controller or grid tie inverter see figure.
If your panels are smaller than 50 watts and use only 12 gauge wires and 20 amp fuses are required.
On jack danmayer s website he recommends putting a fuse or breaker on each individual solar panel.
Fusing solar panel arrays wired in parallel.
Now jack recommends these huge breaker boxes that look like they are the size of a small loaf of bread.
I oversized the cabling between the panel array and the controller to minimize any voltage drop from the panels but i m at a loss as to what size fuse or breaker i should use in this cable run.
There are three different locations that we recommend installing fuses or breakers.
Fuse you need at least one large fuse at the battery to protect the smallest wire you have connected to it.
First between the charge controller and battery bank second between the charge controller and solar panels and third would be between the battery bank and inverter to determine the fuse size needed between the charge controller and battery bank you simply match the amperage rating on the charge controller.
Solar panel charge controller wiring intro solar panel charge controller wiring diagram and step by step guide for off grid solar power system wiring.
