Charging AGM batteries
I have never owned an AGM battery, but the new trailer I am getting will have 2 of them. I replaced the converter/charger in my previous RV with a PD4655V, and am thinking of installing the same i...
Forum Discussion
BFL13 wrote:
I think that is correct--they spec a limit of 30% charging rate on some, so the voltage won't spike too high. AGMs do heat up and you don't want them to blow out their seals. The unsealed flooded type will vent ok and you just add replacement water--can't do that with AGMs.
And unless you have a very smart charger how do you user adjust the current limit to only 30% .... by setting the voltage profile.
Realistically most people don't have a large enough charger and/or have too much resistance in the battery leads to do any damage to an AGM, which is just as well as I found I am over current limited (75 AMPs) to 14 volts even with only one group 24 battery for the first portion of the charge cycle. Most of the time I have more battery than that, so the charge rate is really set by the current limit on the charger if you work get the resistance down on the battery cables and I think that is the typical situation.
With my stock setup, I have now moved the battery to be only about 2' from the charger, even at 14.6 volts output from the charger I only got 45 AMPs into the battery, I was losing .85 volts in the long wires to the front of the trailer at 45 AMPs. I suspect that is a bit more than most, but I think a lot of people lose more voltage than they think they do on the way to the battery.
