Charging AGM batteries

Last year I replaced the Trojan group 27 lead acid batteries, 4, in the house bank of my Camano 31 with group 27 AGMs by Trojan. I had heard different opinions on charging so I asked the distributor in New Orleans. He didn't have a clue so I called the Trojan Service department, and explained my charger had settings for Gel or lead acid batteries but no setting for AGMS they told me it would be fine to use the same setting as used for the Lead/ Acid batteries. I have wondered about this and was at the Trawlerfest in Stuart FL. recently and asked a guy who had a booth displaying AGM batteries, I don't recal the brand but they had a bright orange case, he told me the same thing, to just charge them with the same equipment and setting as the flooded batteries used. The house AGMS are just about a year old now and seem fine so far. I have another AGM 31 for staring my 200 hp Volvo it was installed in July 2005 same charging for it and so far so good!
I just wanted to mention this as there seems to be different ideas on the subject. Has anyone had a different experience?
Steve Willett
Camano 31
Thibodaux, Louisiana

-- Edited by Steve at 12:40, 2008-02-04

Steve:

I just replaced 3 Chinese wet cell 8D's with Interstates AGM's and got <u>exactly</u> the same story. This was done about 3 months ago so I can't say if it is working properly. The volt meter shows 13.5 volts so I guess I'm alright.

Calder is pretty explicit in explaining the differences in the various battery types and the disciplines required for charging.

DS

I've had my house bank East Penn Deka AGM's (and also Optima AGM starting batteries) for 7+ years. When plugged into shorepower, they're charged by a Freedom 10, on the AGM setting of the Link 2000 which contols it. Seems to work just fine. I think that particular AGM voltage profile setting is specifically built for the charging voltages recommended by Concorde Lifeline for their AGM's - which are somewhat lower than the voltages recommended for my Deka's, IIRC. Manufacturers have slightly different recommendations for their particular AGM's.

When underway, charging is regulated by a Balmar MaxCharge 612 with battery temperature sensor, set to the Optima charge profile. I've also tried the 612's AGM profile. Differences in voltages between the two are slight, but I think I get better results (a little quicker and more complete charge) with the Optima setting.

All these settings are not very different from the standard flooded battery settings - not nearly as much different as they would be for gels. The Heart and Balmar documentation show what voltages are selected for each built-in charging profile.

My suggestion would be to find out from the battery manufacturer exactly what their voltage recommendations are, and pick settings that match them the best. And include the battery temperature sensor in your setup. With the 612 regulator, if I didn't like the supplied voltage profiles I could create a custom one with exactly the voltages desired.

"a little quicker and more complete charge"

THE KEY to having a bat set live well and prosper !!

FF

I am usng the same charger as I did with wet cells and mine are doing fine as best I can tell