Solar panel not doing its job?

[Campbrd]

I have a 2012 AI with 2 "6 volt" batteries installed in 2015. It has a 50 Watt Solar charger on top. When it's just sitting on the street with all power "off" the battery seems to be depleting. I thought the solar panel was suppose to trickle charge the battery when not in use. Today the battery was at 12.1 and has been sitting for 10 days with lots of sun on the panel. What could be draining the battery and how do I remedy this?

[uncle_bob]

Hi

Ok, 50W is the panel under crazy ideal conditions. Under "normal" conditions you probably will not see > 80% of that.

You charge your batteries through a DC/DC converter. It *might* be 90% efficient. It could be a lot less.

Battery charging takes place at ~ 13.7V. If your panel is delivering 36W to the battery, that's a bit under 3A. If you get good sun 8 hours a day, that's pretty normal. Net would be 24AH.

Put a good layer of dust / dirt / bird stuff on the panel and your 24AH becomes < 20 AH....

If your batteries are seeing a 1A phantom load, that's going to be 24AH. Things like propane monitors, inverter inputs, control panels all are suspects. That light Bob forgot to turn off when he pulled the chair out of the outside locker is a real good candidate as well. (Hint: look around the trailer at night ....).

So, yes, a lot of numbers and none of them hard and fast. If you have a bit of shade, scale the solar back a bit. End of June in the Arizona desert, scale it up a bit. Could your phantom loads be a bit less than an amp - sure. Could they be a bit more - yes indeed.

First step is to spend some quality time with a current meter to figure out how much current it going where. Next step is to disconnect them and see if the solar controller / charger is still working. It should pull the battery up to 13.7V if it's doing it's thing ....

Lots of fun !!

Bob