Question on deep-cycle battery charging
Posted: Sat Feb 03, 2018 10:53 amGood morning, Ladies! 
I am still puttering away on the solar install for my van. I purchased a 200-watt folding panel array from China (purchased via Amazon) that weighs a hefty nine pounds (!). Heh. Have used them to charge my batteries, and they seem to work well. Easy to take out/take down and put away inside my van. Also purchased three new Interstate 75-watt AGM deep cycle batteries to go with them.
It says on the battery that the "float charge" is from 13.5 - 13.8 volts (these are 12 volt batteries).
I have never put a load on them (have not hooked them up to anything that would pull out "juice" - still working on that part) but I do keep them charged.
Although I don't charge them every day - maybe a couple of times per week - when starting at 12.8 I can get them charged up to 13.2 before I run out of sun (need switch to an mppt charge controller, what I have is an inefficient pwm controller).
My question is this: after charging the battery up to 13.2, if I go out the next day and check it again with my digital multimeter, the charge has drifted back down to 12.8. Does this indicate a defective battery? All three batteries do this.
All replies appreciated!
Thanks.
Anne
I am still puttering away on the solar install for my van. I purchased a 200-watt folding panel array from China (purchased via Amazon) that weighs a hefty nine pounds (!). Heh. Have used them to charge my batteries, and they seem to work well. Easy to take out/take down and put away inside my van. Also purchased three new Interstate 75-watt AGM deep cycle batteries to go with them.
It says on the battery that the "float charge" is from 13.5 - 13.8 volts (these are 12 volt batteries).
I have never put a load on them (have not hooked them up to anything that would pull out "juice" - still working on that part) but I do keep them charged.
Although I don't charge them every day - maybe a couple of times per week - when starting at 12.8 I can get them charged up to 13.2 before I run out of sun (need switch to an mppt charge controller, what I have is an inefficient pwm controller).
My question is this: after charging the battery up to 13.2, if I go out the next day and check it again with my digital multimeter, the charge has drifted back down to 12.8. Does this indicate a defective battery? All three batteries do this.
All replies appreciated!
Thanks.
Anne
