Community Forums

mike367 · 03-03-2020, 10:00 AM

I have a 2004 American tradition and its time to upgrade/change house batteries. The coach currently has exide 27mdcst batteries installed that are coming up on 5 years old. We do mostly campground stops where we can plug in but we also will stay at Walmart overnight on our way to campgrounds.

The batteries seem to charge up ok but will be pretty low in the morning even without using any appliances.

My question is will group 31 batteries fit in the battery compartment and also will the original equipment for the coach (charger, inverter etc) work with group 31's or do I need to stay with the group 27's.
Thanks
Mike

twinboat · 03-03-2020, 10:19 AM

Can't answer for physical size, gp 31s are a bit longer, but as far as equipment, there will be no changes needed.

If your batteries are still doing the job, but seem lower in the morning, you can keep using them until the don't.

Replacing them is a judgment call. If they are lights out dead, then its time, but if they are still at around 11 volts, that's not a big deal.

Upgrading to gp 31s will give you more capacity while dry camping and a bit more length of service because you won't be drawing them down as deep each time.

Is it cost effective ? That depends on the price difference in batteries.

If your looking for more capacity then 4 gp27 batteries, changing over to 4, 6 volt batteries will give your the best bang for the buck.
Typically more capacity and less expensive each.

BCam · 03-03-2020, 10:20 AM

Your current Exides are what as known as dual purpose, deep cycle/starting batteries. Any battery that includes "Cold Cranking Amps" in its specs isn't a true deep cycle battery.

For house batteries, you'll get better performance from true, deep cycle batteries. The least expensive ($99 at Costco), and a good way to go performance-wise, if they will fit, will be two six volt golf cart batteries connected in series so as to provide 12 volts and will be rated at 220 AH. You'll find that the height may be the limiting factor. If they won't fit, true deep cycle 12 volt batteries are available, although generally at a higher cost.

Here's the size of the Costco golf cart batteries:

Length: 10 5/16"
Width: 7 1/8"
Height: 11"

And for Group 27 batteries:

Length: 12 1/16"
Width: 6 13/16"
Height: 8 7/8"

There are numerous threads on this topic, but here's a site with some information that may be of value:

https://marinebatteryguy.com/deep-cycle-battery/

twinboat mentions installing four batteries. This would be great if you have the room but I was assuming that, like with most MHs, your's was designed for two.

Leftys · 03-03-2020, 10:34 AM

If they’re still charging and working, why replace them? They’re low in the morning because they’re running your fridge all night.

Gary RVRoamer · 03-04-2020, 12:24 PM

We owned a 2004 Tradition for years and ran 12v Trojan AGMs in the Group 31 size. They fit nicely. I have attached a photo of my battery bay showing 4 x G31 house and 2x G31 chassis batteries (there are two more batteries in the back, not visible).

Our batteries performed well for about 6 years but noticeably less capacity in years 7 & 8, after which they were replaced.

timjet · 03-08-2020, 07:53 AM

I replaced my 4 12v batteries with 4 GC 6 volt batteries. The battery capacity is the same - 420 AH but at less cost. I have boondocked for up to 7 days at a time with my residential refrig and running the generator 3-4 hrs per day, less if it's cool outside.

I believe the 6v GC batteries are a better alternative than the 12 v batteries. They are designed for deep cycling.

Cat320 · 03-08-2020, 06:17 PM

Quote:

Originally Posted by timjet

...I believe the 6v GC batteries are a better alternative than the 12 v batteries. They are designed for deep cycling...

Last summer we had a friend go the other way....went from four 6V to two 12V, both deep cycle and both AGMs. He's been doing fine.

Gary RVRoamer · 03-08-2020, 07:52 PM

Quote:

I believe the 6v GC batteries are a better alternative than the 12 v batteries. They are designed for deep cycling.

There are excellent 12v deep cycles on the market, but the 6V GC2 (golf car) batteries are often cheaper. At least for the flooded cell type. If AGM is desired, there isn't so much difference in price.

We used Group 31 size Trojan 12v AGM and they lasted almost 8 years.

timjet · 03-09-2020, 04:50 AM

AGM's are a good choice for locations where it would be difficult to monitor the battery fluid level at a cost of roughly 3 times the cost of 6 volt GC's.

Gary got good service from his AGM's. I had 6 aboard my boat and got only about 4 years and using a battery monitor to monitor them. They were deep cycled a lot and sometimes though rarely the voltage got as low as 11.5 volts. That would decrease their longevity.

Gary RVRoamer · 03-09-2020, 10:36 AM

The factory-supplied, brand-x, AGM 12v's in my coach only lasted 4 years. Probably could have squeezed 5 from them, but they were deteriorating in capacity. The replacement Trojan AGMs performed better.