Solar Charge Controller always reading 100%

[martstokeley]

Hey guys,

The solar charge controller in my truck camper is constantly reading 100% charge. This even occurs throughout the night when it is powering a compressor fridge, so does not seem accurate. Any ideas what might be wrong?

Matt

 

[Short_Shot]

Need to know what charge controller you have and what kind of batteries you are using. Lead acid or lithium.

 

[martstokeley]

Sure: 75AH AGM battery. Charge controller is a Steca PR 2020.

 

[martstokeley]

If it is of any help, this controller is pictures here (back when it was saying the battery was lower than 100% charge)

Loose wire on solar charge controller

Hey guys, I just bought a secondhand truck camper that has a couple of solar panels on the roof. When looking at the charge controller today I noticed that the red wire on the right hand side has come loose. According to the display, it looks like the system is still operating to some extent...

diysolarforum.com

 

[mikefitz]

Hi Matt,
The display of capacity with this type of controller is a best guess, but I would have expe to some change over night. What is the battery volts evening and morning?
Mike

 

[time2roll]

Probably a lead-acid based volt meter. Anything above ~12.6 is 100%.

 

[martstokeley]

Thanks for your responses guys. So I picked up a multimeter yesterday to try to get further to the bottom of things. I measured the voltage last night right after I turned the compressor fridge in the camper on - 12.47 volts (controller reading 100%). And then again around 6.30am this morning - 12.56 volts (controller reading 100%). The sun was up at that point (sunrise 6am), but very overcast So I guess I'm left to conclude that the fridge draws shockingly little power overnight and the panels receive charge even in overcast conditions to compensate for a whole night of the fridge drawing power?!?

 

[Short_Shot]

Overcast can still produce power but you're going to be severely limited on wattage.

If it array is large enough that can possibly be enough for a day of fridge power.

Don't forget though that the compressor may cause a voltage drop when turned on that might give you a false sense of charge level. As will any load.

You'll have to keep an eye on charge levels to get a feel for your system on good and bad days.