Showing results for 
Search instead for 
Did you mean: 
Hagerty Employee

Piston Slap: Proper resuscitation for finicky AGM batteries?

When charging an AGM battery, what is the proper way to do it? If I don't have an AGM charger, is there a way to charge it with a conventional charger? (Not necessarily asking for myself, just because I have a lot of experience with them at my job.
Intermediate Driver

There's no concern with hooking a good conventional battery directly to an AGM battery that's over-discharged? Won't the AGM battery draw a *TON* of current from the conventional battery at first?
Community Manager

Probably not, provided you connect the charger to the batteries in a matter of seconds, not minutes. 


Ah, man, I recently purchased a new battery for my motorcycle because the old one wouldn't take a charge after I inadvertently let it go dead. I tried to charge it with a Battery Tender Jr. It seems that older model doesn't have the features needed for proper AGM battery charging and maintenance.