The chargers made for AGM charge at a higher voltage than regular chargers so I don't know if the lower voltage will make them last better, or not. Contrary to the ad claims, I think that once one has been run down due to something pulling them down, they seldom seem to return to a completely charged state. The one in my Challenger has not been on a charger for at least three months until I dropped it down yesterday and hooked it up. It showed 12.42v and went to a full charge with a green light showing in a bit over an hour. The CTEK charges AGM at a voltage above 14v until it hits fully charged and then drops down to about 13.5v.
The other Red Top that I have will quickly drop to just above 12v and will never show the fully charged state although it eventually starts cycling on the charger anyway. After two weeks, it will barely turn over if I go out to start the car.
When this thread initially started, I began researching Optimas and found the net was flooded by unhappy owners-far more than I recall hearing about ten-twelve years ago when I bought the first one.
See the first post on this page
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2052956He explains their quality control in Mexico is better than it was when they built them in the states. I just recall they took the prorated part of the warranty and tossed it about that time so I am not buying it.
If Sears will have a good battery sale, I will try a Platinum because the warranty is good and the Odyssey has had a good reputation even tho most are referring to the lightweight model for race cars.