Hi, new to forum, thanks for all the great info. I have a problem with a simple 12 v solar system in my boat... a 12w panel, going to a morningstar/sunguard SG-4 charge controller, going to a fuse on the positive controller output, and then to a deep cycle marine battery. I use it to keep that battery topped off. The problem is... when I test output from the charge controller, I get nothing, not even the "negative voltage" you see when polarity is reversed. But, if I switch the panel output polarity (going into the controller), I get correct voltage if i also switch polarity on the output of the controller as well. BTW the panel tests fine without the controller, and polarity is normal, exactly as indicated on the panel itself.
Before I replace the controller, I have a few questions:
Do you think the controller was wired backwards at the factory? Is it possible that the polarity reversed when the contorller failed? I've never heard of that.
Is it OK to put a load on the battery while the panel/controller is connected, for starting the boat? I've read different views on this.
Is it OK to switch the battery switch while the panel/controller is connected? (the solar system is hardwired to the deep cycle battery, but that battery and another battery are connected to a standard switch... 1 -2 - Both).
Any suggestions for a simple charge controller to keep the battery topped off? I definitely want a floating charge, and PW to keep the lead acid deep cycle battery in good shape.
I'd wired everything correctly, checking resistance on the wire runs (15' from panel to charge controller using 16 guage wire) to ensure I was maintaining polarity, and installed in my boat. I couldn't really test the output from the charge controller when I installed it in the boat last spring (total shade), but it's pretty darn simple so i figured it would just... work. Never really knew for sure if it was keeping my battery topped off, until last weekend the battery was completely dead. That's when I ran the tests. I've always covered the panel when connecting/disconnecting.
Any help will be appreciated!