Can't figure out why it's charging so slow

[Electric Mayhem]

Hey y'all, I have 275watts of solar and bright sunny days, but my charge controller is only showing a charge rate of .4-.6 amps in full sun. Any ideas on what the problem could be? I cleaned the dust off the panels to no avail.

 

[Electric Mayhem]

Ok I climbed on the roof and unclipped my 100 watt panel, leaving only my 175 watt panel. Charge rate went up to 3.1 amps. Clipped the other back in and sure enough, back down to .5 amp.

 

[B and C]

First question, has it ever worked or is this a new install?

 

[Electric Mayhem]

This has worked. I recently upgraded the controller. I also just went back to only the 175 watt panel and now it's only showing .5 amp. I'm so tired of trying to learn about solar.

 

[B and C]

Just saw that you have mismatched panels. My guess is the 100 watt panel is a low voltage version and the 175 watt is a high voltage version.

JiminDenver did some tests with mismatched panels and what he found is poor overall performance when mismatched panel were employed. You would be better served by having each panel on its' own controller.

 

[Electric Mayhem]

Ok thank you

 

[highdesertranger]

when mixing different panels the voltages must be reasonably close together. mixing a 20v panel and a 40v panel doesn't work, they don't play well together. but you can still use both panels you just need two different controllers. also the outputs of the controllers must be close to each other. highdesertranger

 

[bass_sears]

Just to make sure we're covering all our bases here, do you need the power? In other words, are your batteries drained down enough that they'll take a charge? I only ask because I've made this mistake before, if your batteries are fully charged your panel output will seem very very low. What happens if you turn on a bunch of loads?

 

[Electric Mayhem]

It's always hard to tell because when they are actually charging, the indicator always shows full no matter what. Today I did see it was a little low before it started charging again. I don't really have a bunch of loads to turn on. Just my fridge and phone charger. I don't even have my lights hooked up atm.