Battery Redo - Montana Owners Club

masterdrago · 03-04-2019, 07:49 PM

I'm trying to formulate a plan ahead of time to replace the two 12 volt marine "deep cycle" (what a joke) batteries that came in the 3791. We will most likely not ever boondock and I don't anticipate installing solar, although the 5r has pre-wiring for it. I've priced Trojan, Duracell, and Lifeline. The price difference is rather astounding. I've read that the golf cart 6 volt generally have extremely long life and recharge capacity and $/Ah seems to be generally lower. Here is the dig. If I just replace with a similar battery that is already installed, it not only will save major coin up front but save my back also - I saw the weight of some of those 6 volts! Yikes!! Any comments might be helpful and I know this subject has been run over more than a couple of times.

rohrmann · 03-04-2019, 08:08 PM

When we purchased our rig, the dealer had installed two grp 24 Centennial RV/Marine maintenance free batteries. They worked great. A few years later, prior to doing a little dry camping with the help of a small Honda generator, I upgraded to grp 27 batteries, same brand and type, and they also work great. Never have to add water, just occasionally check connections. Unless or until we ever install solar, these batteries do the job with minimal hassle.

masterdrago · 03-04-2019, 08:49 PM

The only reason we might consider "real" deep cycle batteries as replacements is that there are times when we might want to run the refer through the inverter for extended periods. The inverter will not shut down until the input DC voltage is 10.5. That's really drawing them down low.

PeteandJoan · 03-04-2019, 09:27 PM

I am also replacing 2-12v (24's) and have res refrigerator and thinking 2-6v AGMs and am very interested in this post and will monitor and hope I can settle on the best bang for the buck. No boon docking or solar in my plans. The more info the better.

I just replaced my 2-12v in my truck with AGMs while I was in Calif. over Christmas holidays and did not have time to do research so bought Interstate because they were closest to me. But I have plenty of time on these and can look for the best buy. Centennial has a great warranty if I remember correctly (3 yr replacement ?) but dealers appear to be scarce .

Thanks.

Texan · 03-05-2019, 12:52 AM

I have 2 of the Trojan 6- volt batteries and they seem to work very well with my Honda 2000 inverter generator. I have only boondocked a couple of times but they did real well. I have even used the central heat all night set at 61 degrees when it was in the upper 30's and had no problem charging them up the next day. The 6-volts are heavy but I bought me a battery strap to lift them and it makes it much easier.

masterdrago · 03-05-2019, 07:40 AM

I think that I do want to go with the 6 volt system but I'm fairly sure that I cannot lift and bend over to get them into the battery box of our 3791 at 100# each.

Theunz · 03-05-2019, 08:01 AM

I bet you can get someone to lift the batteries for you. Once the're in it should be several years before they need to be removed, and by then the friend who initially helped you will have forgotten what a pain (pun intended) it was.

**AZ Traveler** · 03-05-2019, 08:16 AM

Stick with a pair of grp 27 batteries if you do not plan to boondock. That would be the easiest replacement. Going with 2 golf cart batteries will provide a little more AH but you would need to swap out your battery box also.

twindman · 03-05-2019, 08:26 AM

I am pretty sure my 6V batteries are around 68-70 lb. a piece. No where near 100.

Texan · 03-05-2019, 09:36 AM

Quote:

Originally Posted by masterdrago

I think that I do want to go with the 6 volt system but I'm fairly sure that I cannot lift and bend over to get them into the battery box of our 3791 at 100# each.

The Trojan t-105 battery weighs 62 pounds. I bought mine at Golf Carts of Houston just north of Humble on Hiway 59. You might want to call and check the price. They also have Crown batteries which are very well known in the golf cart industry and cost a little less. Either should last you many years trouble free if you take care of them. I keep a battery maintainer on mine and add water about twice a year.

Baldicon · 03-05-2019, 10:09 AM

I have a residential refrigerator in my 3121RL. It came with only one battery. Was it supposed to have two?

2 Yoopers · 03-05-2019, 05:49 PM

Depends on the dealer. I have a 3711Fl that I bought used that has the residential fridge. It only had one battery when I purchased it, but they installed 2 new batteries in a double battery box when I took delivery. Dealer said it comes with 2 due to the fridge.

DarMar · 03-05-2019, 07:16 PM

When we bought our 3721 we requested two 12 volt as part of the deal.

Dealer installed double battery box with two group 24 batteries. We have the "in comand system" that requires a minimum almost 11 volts to operate. We found the two 12 volt group 24 could quickly drop below that.

Just recently bought two Rolls 6 volt 235Ah batteries and looking forward to a much improved system. Our Rolls 6 volts weight 67 lbs each.

Montana Man · 03-05-2019, 08:58 PM

We don't boondock and we live on one 12v AGM no problems. More would be better but if I don't need it, I don't need it. The Honda 2k has yet to be used.

Normal Norm · 03-10-2019, 01:39 PM

Quote:

Originally Posted by masterdrago

I'm trying to formulate a plan ahead of time to replace the two 12 volt marine "deep cycle" (what a joke) batteries that came in the 3791. We will most likely not ever boondock and I don't anticipate installing solar, although the 5r has pre-wiring for it. I've priced Trojan, Duracell, and Lifeline. The price difference is rather astounding. I've read that the golf cart 6 volt generally have extremely long life and recharge capacity and $/Ah seems to be generally lower. Here is the dig. If I just replace with a similar battery that is already installed, it not only will save major coin up front but save my back also - I saw the weight of some of those 6 volts! Yikes!! Any comments might be helpful and I know this subject has been run over more than a couple of times.

I just bought the 3931 and already the lead acid batt is going bad, I would like to purchase the lithium and I think I will keep the lead acid only to install when I have it fixed at Camping Workd sence those guys are a bunch of monkeys and drain my battery to 0 volts,

masterdrago · 03-10-2019, 01:46 PM

Quote:

Originally Posted by Texan

The Trojan t-105 battery weighs 62 pounds. I bought mine at Golf Carts of Houston just north of Humble on Hiway 59. You might want to call and check the price. They also have Crown batteries which are very well known in the golf cart industry and cost a little less. Either should last you many years trouble free if you take care of them. I keep a battery maintainer on mine and add water about twice a year.

You're correct. I think the one I might have been looking at was theJ305H-AC Deep-Cycle Flooded which is 98# and would not fit in our battery box. Or the Duracell SLI6v305S which is also too tall. A group 27 does make more sense.

laverdur · 03-10-2019, 02:48 PM

I almost never boondock (once in 13 years). My Monty stays on shore power when stored on the pad at home. The original Centennial grp 24 batteries (2 of them) lasted seven years. Never had to add a drop of water. I so wish that Centennials had been available in ND when I had to replace. Have Interstate now and I have to top up the cells every few months. Grrrrr.

SteveG · 03-10-2019, 02:57 PM

Which ever battery you choose be sure your converter is designed to charge the battery you select.

Nighthawk · 03-10-2019, 06:49 PM

About 6 years ago I needed to replace my 2-12v batteries and decided to go 6v at that time. I bought 2 6v Crown batteries, which I was told were as good as Trojans, but I had my doubts. Within weeks, I found 4 - 6v golf cart batteries at Costco for $50 CAD each and grabbed them up. The local Costco just wanted to get rid of them. What a steal! For 6 years I've had 6-6v batteries in my battery bank. Late last year, the Costco golf cart batteries were on their last legs and replaced by batteries with 4 - 6v Trojan T015s. I still have my Crown batteries and they still are holding a good 12.67v charge.

I am very impressed with the Crown brand as they have stood up very well - 6 years and still good.

That's my 2 cents worth.

makahaskipper · 03-10-2019, 07:41 PM

There was a mention of using lithium batteries. You need to make sure your converter is compatible with them. Also the deal breaker for me was that most can’t be charged below 32°. The built in BMS (battery management system) will prevent charging below that temp. Not a problem for you AZ bound folks but up here in the great white north we have to find a way to keep them warm. Notoriously hard in the leaky compartment meant to hold a generator.

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