I just replaced two trolling motor batteries because one of them would not take a charge. Since it’s my understanding that it’s best to have closely matched batteries in age and use I got two new ones. Of course the bad one went in for the core charge.
The other battery was still charging and seemed to function ok. It is an Optima Blue Top Group 27. The new batteries are Duracell AGM group 31.
Any suggestions of what to do with the Optima that still seems to be ok? I currently don’t have a stand-alone charger but thought about getting a budget-friendly one to keep the battery on and keep it as an emergency back up.