Interesting stuff. I did some extensive research on the AGM batteries and my understanding is that in order for them to really work properly in a car and be fully at home, the alternator needs to have the added ability to sense them and use a different set of parameters for charging. Also, any battery charger used to charge one up also must have that same extra set of different parameters or just trickle charging used. Otherwise the battery can be damaged. Apparently, as long as the charge is close to full a regular alternator can handle them, but below a certain charge level it becomes a problem. I understand it is now possible to get an alternator with this added functionality, as well as battery chargers.
This new tech does hold promise, but I think that when I replace mine I will just go to a larger battery and stay with lead acid. Of course it has its own drawbacks. While some battery types struggle with hyper-cold conditions, here in Texas we have the opposite - hyper-hot! In the recent past I have not had a single battery (and I only buy the best) last more than two years. With summer heat waves that sometimes top 110-115 degrees, and summers with 50-60 days of continuous periods of 100+ degrees, my new batteries seem to do okay with their first summer but fail after number two. Aargh! So I get the Motorcraft batteries with the 3-year free replacement warranty (the best warranty available), and just last month, when my two year old one in my F250 went South, I got a new one free. Beauty, eh?
