Fuse in small solar setup

walt

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Jun 1, 2007
3,541
Macgregor 26S Hobie TI Ridgway Colorado
I think the 30 watt will overall be a good choice. Likely aready mentioned but try and avoid even a small amout of shading as you will get a disproportionate amount of solar power loss.

Just a little extra note on the fuse. The fuse between the charge controller (which you absolutely need) and the battery is the important one and lots of good advice already given.

A fuse between the controller and the panel is the one that's harder to figure out and I would likely just go with what the controller manual says.

The details.. you can short a solar panel all day long and no problem at all. The problem is that if there is a charge controller that is hooked up to a battery and the solar panel is generating power, this will turn on a circuit in the charge controller that is very sensitive to being shorted. My personal experience is that once I had some sort of fuse between the panel and the controller that was rated at slightly higher current than the panel could ever put out. But.. I accidently shorted the wires at the solar panel on a sunny day and the fuse did not blow but the input circuit to the charge controller did blow. I ruined the charger controller.

Someone mentioned putting a blanket over the solar panel anytime there is the slightest risk of shorting the wires between the panel and the controller. I think this is generally good advice. This may not be necessary with every type of controller but the only way to know for sure is the short things which more than likely will damage the controller. And of course you do not want to use alligator clips to connect the panel the controller as that adds big risk for shorting things.
 
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Oct 24, 2010
2,405
Hunter 30 Everett, WA
Thanks to everyone for the replies. I was hoping to just order all of the pieces I needed and then put it all together without fabricating stuff. Still looking...

Based on the specs, it looks like the panel I was considering does not actually come with the MC4 connectors after all. It also says it's 16awg wire leads. I had been planning to use 12awg for everything else. Now I'm not so sure.

[Edit] If my panel has 16awg leads and I'm using 12 elsewhere, on what do I base my fuse size? Or, is mixing wire size a no-no to begin with?

I really appreciate everyone taking the time to give me feedback. I might be back to the drawing board. Ha. :)
No problem connecting 16 to 12 guage wires. Fuse it for the smallest wire. If your panel is under 100 watts 10 amps is fine.

Ken
 
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