New Coach Batteries

[Bionic_Man]

It is about time to change batteries in the coach. I have the standard two 12-volt system, which I think I will stay with. But I am considering going to AGM batteries.

When we camp, we usually have electricity. At least until fall when we put the boat away, and then we switch to more federal lands in the mountains without electricity. The RV is stored at home, and is left plugged in so that we don't have to load/unload the fridge every trip. I do my best to add water to the batteries over the course of the year, but sometimes I forget.

Would there be an advantage to going to AGM batteries in the above scenario?

[BFL13]

No. AGMs need to be fully recharged frequently. That means you need to get them to where amps have tapered to 0.5a/100AH and hold the voltage at about 14.4 till that happens before dropping the voltage to the float voltage.

You must have an ammeter to tell you when you are there for amps, and a charger that can hold that voltage all the time it takes. I use my Trimetric for the ammeter job, and have an adjustable voltage converter (PowerMax LK type) to do the voltage part for my AGMs.

Only reason to have AGMs is if you need to mount them inside the RV where the fumes from a Wet battery cannot be allowed.

[time2roll]

AGM is a bit more sensitive to undercharging. Best to verify the charging system meets the charging specs of the new battery.

Yes there are advantages to AGM. No corrosion, no water to check, some resistance to freezing, a deeper discharge is better tolerated, higher resting voltage, faster charging, higher CCA rating for high load items (less voltage sag).

[pianotuna]

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