Issue charging a 12V battery using solar charger

batterieschargersolar cell

I bought a 12V solar charger for vehicle batteries, because I am usually using wall chargers and I wanted to give green technology a try.

When I connect the solar charger to my battery, it shows 10V, and it was the same after two sunny days of charging. If I connect wall charger to that battery, it does show 13V and the battery does get charged after few hours.

When I measure solar charger outputs, it shows 18V, but if I connect it to battery, it falls to 10V.

When I measure wall charger output without the battery it shows 13V, if I connect it to battery, it still shows 13V.

Is there anything wrong with the solar charger? Or is the battery bad, because it will not allow to be charged from solar charger? What can I check? And how I can troubleshoot this?

Best Answer

and thanks for your replies. I connected the solar charger to my car battery and after a few hours my car would not start. So, i decided that this solar charger has a n issue. I measured the charge and it was about 18V. The problem was that it was -18V and not +18V. The manufacturer installed the output cable so that it has an inverse polarity. It took me 2 batteries to destroy before realizing the above. I will contact the manufacturer to see what they suggest, an in the meantime, i just connect it deliberately wrong (minus of the solar charger to a plus of the battery) and it chargers fine.