My step daughter has a 2010 T&C Limited with a 4L engine that is going to need a new battery. I have been looking online and some sites recommend an AGM (absorbed glass mat) battery for this vehicle. While at a parts store today, they listed both AGM and non-AGM batteries for the application, and when I asked the counter person, they really didn't say, talking more about CCAs. Just wanted to get opinions on the matter since I have never dealt with this to my knowledge.

 

AGM (Absorbent Glass Mat) refers to the separators between +ve and -ve plates. Some has coarse together with fine glass fibre. Chief advantage is a lowering of amount of acid, chief disadvantage is a tendency to "stratification" of acid, weaker at the top, stronger at the bottom after time. The acid electrolyte cannot circulate. It is said this technology requires a higher charge voltage, but I can't see why. Calcium-calcium batteries loaded with silver as alloying the lead plates does need a higher charge voltage because of raised ionic potential from the other metals.

Plenty of people here have found suitable replacement batteries for GVs and no doubt they will appraise you shortly.

Lead-acid batteries will degrade and lose capacity if they are left on the shelf too long at the retailer, (if he doesn't keep them float-charged) so see that you buy from a fast mover of these batteries. In the old days, this degradation was prevented by supplying "dry-charged" i.e. no acid. This was installed by the garage from a huge carboy of acid of the right gravity. Modern sealed and AGM batteries cannot be supplied dry-charged.

Leedsman.

 

Any others?