Replace Lead Acid Coach Batteries with AGM batteries ?

[Skynardo]

I pulled my original house batteries out today as they would not maintain a charge and were not maintained as they should have been. I was going to buy replacement interstate batteries at Costco, but had read a few threads indicating AGM may be a better way to go. Looking for opinions here. Some reading mentioned the converter may not handle charging AGM batteries correctly and Im not sure how to determine this. I have a 2018 Sunseeker MBS with 2 house batteries and a PD4080K power converter. Any advice appreciated.

[sdelam]

If you don't mind the cost and want a maintenance free battery than AGMs will work just fine with your converter.

If you are willing to keep the water levels toped off than a standard flooded battery will be cheaper and also work.

[NJKris]

Agreed. Your only real advantage in the RV with AGM is if they are difficult to access to top off with water. Mine sits in driveway and with my battery waterer can is a cinch to keep topped off. Either way, you'll be better off with real deep cycle batteries, which the ones you have now don't appear to be (looks like dual purpose batts).

[Skynardo]

So you charge them the same way? Once a month when in storage and after every trip? Will the wet battery last longer if maintained correctly?

[NJKris]

Yes a 'wet' batt (flooded lead acid, or FLA for short) will last a very long time if not left discharged and water level is maintained. AGMs can tolerate a higher charging voltage and therefore charge faster. I don't think people change converter out to a special AGM charger. I made the mistake of paying a lot extra for an AGM for my Corvette, it charges with the stock alternator just fine. But I keep my smart charger/maintainer for the Corvette now set to the 'snowflake' cold temp setting, which raises charging voltage a bit, so it supposedly charges faster.

[Skynardo]

I think I will go with wet batteries and make sure they are deep cycle. They are easily accessible under my RV step so no big deal to water them. So the best way to verify fully charged is to check voltage with multi-meter after disconnecting from shore power/turning switch to OFF position?

[MNtraveler]

Originally Posted by Skynardo

So you charge them the same way? Once a month when in storage and after every trip? Will the wet battery last longer if maintained correctly?

That will work as long as you totally disconnect the batteries when in storage. Charging after each trip may not be needed as the chassis alternator charges them well while driving. You can tell by checking the voltage after you stop driving for about one hour to let the surface charge fall off. If you are going to keep the refrigerator and some lights going for a while after that, then charging would be in order.

PS: when my FLA batteries stop doing their part, I plan to replace them with similar types. Bought our 2016 model in Fall 2015 and the original batteries are still very good (had to replace the chassis battery once in the dead of winter).

[Dbrote]

I have pretty much the same rig. 2016 MBS 2400R. I replaced the 2 flooded group 27 batteries with 2 Group 31 105 amp AGMs. They just fit. I keep the rig plugged in at home so they are always charged. No problems at all and they really last in use. Kept the same stock progressive converter. I added a VictronConnect Bluetooth shunt.

[A32Deuce]

I have 2 AGM for the house part of my SunSeeker and an AGM under the hood. Also the other 4 vehicles have AGM battery's. Wont ever go back to wet battery's again. My 2 classics are on a Battery tender when we go away in the winter and they are not disconnected. I have used AGM bats. since the turn of the Century.

[GFD47]

2015 FR Wildcat Maxx. Switched to AGM's when originals gave up the ghost. I'm lazy and like not having to remember to add water. AGMs are a close cousin to flooded, so no changes needed re my original converter. My AGMs are a larger size than the flooded, so I had to get bigger boxes. Still fit on the tongue (barely) with a modified mount.

[Skynardo]

Originally Posted by Dbrote

I have pretty much the same rig. 2016 MBS 2400R. I replaced the 2 flooded group 27 batteries with 2 Group 31 105 amp AGMs. They just fit. I keep the rig plugged in at home so they are always charged. No problems at all and they really last in use. Kept the same stock progressive converter. I added a VictronConnect Bluetooth shunt.

So no issue with overcharging and AGM? Do you leave your converter in the ON position when plugged in at home?

[tomkatb]

Best choice is the gc2 battery. Longest life low cost. If you take care of them.

12 volt batteries that say multi purpose, deep cycle, marine etc are mostly car batteries. Different construction often. Smaller thinner plates for better starting of cars , trucks and boats.

However gc batteries are taller and might not fit. Also, level indicators make them taller. Folks with level indicators tend not to abuse their batteries.

AGM are sort of pricey. They tend to shorter lives. Improperly maintained wet cells can be damaged in a year or two.

Here, two lithium look real good. Double the amps.

[NXR]

Contact Progressive Dynamics and ask them. They responded to my query about my PD9270 and AGM batteries in a day. Mine works on either so perhaps yours will also.

https://www.progressivedyn.com/contact/

Ray

[Skynardo]

Originally Posted by MNtraveler

That will work as long as you totally disconnect the batteries when in storage. Charging after each trip may not be needed as the chassis alternator charges them well while driving. You can tell by checking the voltage after you stop driving for about one hour to let the surface charge fall off. If you are going to keep the refrigerator and some lights going for a while after that, then charging would be in order.

PS: when my FLA batteries stop doing their part, I plan to replace them with similar types. Bought our 2016 model in Fall 2015 and the original batteries are still very good (had to replace the chassis battery once in the dead of winter).

So totally disconnected means what in the picture above? Remove the negative cable that is not connected to the 2nd battery. Or something else?

[MNtraveler]

Originally Posted by Dbrote

I have pretty much the same rig. 2016 MBS 2400R. I replaced the 2 flooded group 27 batteries with 2 Group 31 105 amp AGMs. They just fit. I keep the rig plugged in at home so they are always charged. No problems at all and they really last in use. Kept the same stock progressive converter. I added a VictronConnect Bluetooth shunt.

Like one week ago I just added the same Victron SmartShunt. My training on it isn't complete yet as it's back in storage, but not for too much longer.

[MNtraveler]

Originally Posted by Skynardo

So totally disconnected means what in the picture above? Remove the negative cable that is not connected to the 2nd battery. Or something else?

Yes but then put back on the negative cable that connects the two batteries so they keep each other in balance. A knife switch that disconnects the "all negative loads" cable would make it faster and easier.

[RedRoverComeOver]

Surprised weight hasn't been mentioned. AGMs are going to be heavier as well as golf cart batters compared to flooded.

[NJKris]

Originally Posted by RedRoverComeOver

Surprised weight hasn't been mentioned. AGMs are going to be heavier as well as golf cart batters compared to flooded.

Golf cart batteries ARE flooded, you mean AGM golf cart batts are heavier than FLA?


My GC15's are 64lb each, so 128 lbs plus cables at least 130 lbs.

[Dbrote]

Originally Posted by Skynardo

So no issue with overcharging and AGM? Do you leave your converter in the ON position when plugged in at home?

Yes. Always on and the refrigerator is always on also. Often we travel by air and we store some extra food in the RV.

[tomkatb]

From what I have seen.

In wet cell batteries and agm, the weight has to do mostly with the storage. folks often compare series 24 batteries with gc2 batteries with the same footprint. However the gc battery is substantially more amps in general.

Lithium is the only way to save weight.