View Full Version : AGM batterys

mike kelly
08-04-2001, 12:01 PM
I've recently purchased a GNB powercycler ,agm type battery.my question lies in charging. The manufacter says a special type AGM type charger is required.Reading Oct 2000 issue of Practical sailor their comment is that a regular type charging system can be used. Does anybody have any exerperiece with these.Can you just use your alt. of yiur engine keeping track of the amps?How does this work in the real world. Thanks

08-04-2001, 12:30 PM
Practical sailor is correct....but the manufacturer will tell you how to extend the period between your present battery and buying a new one. Some of these batteries will have much extended life spans if you use a charger that has a controlled voltage and current supplied to supply them...additionally the specific charger may have a pulsed type of "topping off" charge for the battery. Most chargers reach about 90% charge and then shut off or have such a high voltage applied that they never shut off and continue to "overcharge" the battery.....listen to the manufacturer.

08-04-2001, 12:33 PM
I replaced my boat's 2 batts w/ Lifeline AGM batteries for reasons of lower maintenance and fitment (I could get more capacity by laying larger batteries on their side, which you can do w/ AGMs and not affect their performance). The literature I got said that if your charger didn't have a separate AGM setting to use normal flooded cell voltage settings. If you only charge w/ the alternator, I would highly recommend getting a multistage regulator such as those made by Balmar (ARS-4 or MC-412) or Link. Most of them have separate voltage settings optimized for specific battery types. They do require an alternator wired for external regulation though. An original equipment internally regulated alternator can be converted by an alternator shop for relatively little money, bringing the field excitation line out so it can be connected to the external regulator. A high output marine alternator would be even better. You will get much better charging and reduce the chances of damage to your battery.

mike kelly
08-04-2001, 05:37 PM
thanks for the replies, good to here aboat the balmar regulaters. I have external reg. now, sounds like that might be the way to go. as i plan to spend most of the time off the dock