Solar Battery Charge Issue

KenS999 wrote:
Hello I have a 100W Renogy solar suitcase charging two AutoZone Duralast lead acid Marine deep cycle group 24 batteries. Batteries are 3 years old. Lately I have noticed the charging cycle time drastically increasing especially during the absorption phase of the charge cycle. Charging is now nearly twice as long as before. I have cleaned and inspected the terminals and connections. I have checked individual cell fluid levels as well. These batteries have been babied and never taken below 12.3V. My power usage requirements are minimal and have not increased.

I am wondering if these batteries are just getting long in the tooth as far as charging cycles? Would investing in a good specific gravity battery tester be the next step?

Thanks, Ken

Sounds like your batteries may need to be equalized (cells restored to equal) as the plates may be sulfated. This is normally done every month or two by a controlled over charge of about 14.8-15.1v for about 20 minutes or so which returns the sulfate back into it’s chemical soup...This should help to reduce the battery’s internal resistance...

3 tons