mfilippello
New Member
I think a lot comes down to how well the batteries are made as well. Both of these are really good batteries and can tolerate a lot. Dont have as much faith in the Johnson controls Advance battery Mine might even be made by Clarios. Need to pull it and see what I can find on the case and see what specs I can get.My Odyssey-made Diehard Platinum and Northstar AGM batteries have done perfectly well using the stock TJ charging system. The previous Odyssey lasted over ten years and my current Northstar is over 5 years old.
Here is a decent read on the topic. https://workshoppist.com/car-alternator-charge-agm-battery/
Can't ask for much better than 10 years but one has to wonder what would change if the battery was to get proper absorption charging for a true 100% charge. AGM batteries need an absorption phase to reach 100% otherwise sulfation sets in and capacity is reduced. Bulk charging is done around 13.6v but that only gets the battery to a partial state of charge. Jerry, do you also throw your batteries on a line fed charger from time to time?
another good read https://www.practical-sailor.com/systems-propulsion/fighting-sulfation-in-agms