Battery Drain - Montana Owners Club

KemoLondon · 06-08-2018, 05:09 AM

Ok I did a quick search and didn't find an answer already posted so here's my problem. Brand new 3720rl (only six trips so far) and when we get back and leave the rig parked the battery seems to be dead when I go back in to open up/turn lights etc. But when I hook up to shore power everything seems ok. Going to have the battery tested but could there be an issue with the inverter?

Bob

Mudchief · 06-08-2018, 05:30 AM

Hooking up to shore power and everything works says your inverter is working. However I would take a volt meter and disconnect the positive on the battery and make sure you have 12 volts going to the cable connecting to the battery. If you are letting the rig set for days there are things that are drawing from the battery. If that is the case you need to disconnect one of the battery leads.

**Carl n Susan** · 06-08-2018, 10:03 AM

I am guessing you are leaving the Montana for a few weeks, you have one small battery installed by the dealer, and you may, or not, have turned off the battery disconnect.

There is a continuous 12V power draw regardless of the position of the battery disconnect. Obviously it is higher if the battery is not disconnected. These parasitic draws will drain a 12V battery, especially a single small one, in a short time. The best plan is to disconnect the ground cable at the battery when you are going to leave it. Having the battery tested will provide peace of mind that it is OK (being new it should be).

P.S. Montana's have a Converter (which produces 12V from a 120V supply) rather than an Inverter (which produces 120V from 12V).

BuilderBob · 06-08-2018, 10:35 AM

What Carl said if you park and it's not hooked to some kind shore power it wont take long to kill the one battery that you have! If you leave it set pull the nag battery cable.

**DQDick** · 06-08-2018, 01:39 PM

Just to elaborate there are a number of things like the LP gas detector, for instance, that run on 12v and aren't disconnected by the battery disconect switch.

KemoLondon · 06-08-2018, 02:02 PM

Thanks all. Good stuff. Seems kinda strange to have a dis-connect switch that still allows the battery to be drained. Oh well. Will take your advice and either pull the cable or hook up to shore power while in driveway. Thanks again.

bobkinner · 06-08-2018, 02:18 PM

I am wanting battery suggestions, what kind are you using?
thank you

jcurtis934 · 06-08-2018, 04:11 PM

Start a new post bobkiner

Texan · 06-08-2018, 04:22 PM

Most likely you have the cheapest 12 volt battery the dealer could find. If you plan on doing any dry camping then i would suggest going with 2-6 volt batteries which would give you same voltage but double the amperage. Many go with the AGM batteries with no maintainence. I have Trojan 6-volt golf cart batteries that i add water to about twice a year. Sam's Club sells 6 volt batteries that are popular but not the quality of some others including the Trojan. If you stay with 12 volt then Interstate makes a good battery. There will be plenty of people who will probably chime in on there preference. If you have access to power then i would suggest you keep an battery maintainer on the battery at all times. I have an Deltran 1.25 volt maintainer which is excellent and of good quality. In fact i have 3 of them for various applications. You can find these at Wal-Mart, Lowe's, Home Depot and the internet. The cost is around 40 to 50 dollars.

phillyg · 06-09-2018, 04:03 PM

Neither of the two mfgr. installed disconnects on my rig completely disconnect everything. My two batteries will be drawn down in two weeks. Put a simple knife switch cut-off on your negative cable to eliminate parasitic draws.

CaptnJohn · 06-09-2018, 08:22 PM

I have 2 marine deep cycle #27 batteries. I installed a cut-off at the batteries that shuts off everything! They have sat for nearly 3 months and still held their charge.

KemoLondon · 06-10-2018, 05:47 AM

Well I'm not sure that a constant battery drain being normal is a comfort but at least now I now I'll be throwing the dis-connect (or pull cable) while in between camping. Kinda funny the dealer did not stress doing that since it seems to be common knowledge within the community. Thanks again for the feedback folks. I learned something.

jeffba · 06-10-2018, 07:38 AM

Yes that was not mentioned in my PDI either.

**Carl n Susan** · 06-10-2018, 11:14 AM

Quote:

Originally Posted by KemoLondon

<snip>
... Kinda funny the dealer did not stress doing that since it seems to be common knowledge within the community....
</snip>

I think you will find that the people on this forum collectively know more than any dealer you will encounter.

Twopetes · 06-11-2018, 07:44 AM

Morning, Not trying to hi-jack this post but my question is in the same vein.

2015 Montana 353HC with a residential frig. The inverter works (had to replace it last year) and I have two 12 Volt batteries. If there is another post on this - apologies in advance, but I could not find one.

Questions for those who have a set up like this. How long will your batteries run the frig? We don't boon dock (not retired yet) but we will stop at a Cracker Barrel overnight and I will run a small Honda generator until 10 but then it is the batteries and inverter. Not much else is on except a LED night light. How long should the batteries last?

Second question is the 6 volt vs 12 volt discussion. Would 2- 6 volt golf cart batteries last longer than the 12 volt batteries?

Thanks in advance - Steve

phillyg · 06-11-2018, 08:12 AM

Quote:

Originally Posted by Twopetes

....... How long will your batteries run the frig? We don't boon dock (not retired yet) but we will stop at a Cracker Barrel overnight and.....Would 2- 6 volt golf cart batteries last longer than the 12 volt batteries?

Under those circumstances two class 27 marine/RV deep cycle batteries should keep your fridge running overnight. I don't know the definitive answer to two 6v batteries.

**AZ Traveler** · 06-11-2018, 10:00 AM

Second question is the 6 volt vs 12 volt discussion. Would 2- 6 volt golf cart batteries last longer than the 12 volt batteries?

Depends on the size of the batteries but in general you will do better with two 6 volt batteries.

jeffba · 06-11-2018, 11:09 AM

it also depends on ambient temp. Hotter it is in the camper the amount of time the batteries will last

jcurtis934 · 06-11-2018, 04:30 PM

If you used two 12vdc group 31 agm batteries in parallel for 220 amp hrs of service, you would be the same as two 6vdc golf cart batteries in series...exception being sealed for agm and no water or gas outs to worry about. It really is all about personal choices. Mine was for marine agm batteries from the same plant that makes Deka batteries.

glw1973 · 06-13-2018, 04:13 PM

I had issues as well with my battery. My dealer told me that typically, you can only get 2 yrs out of a battery. Really more like one year. Does this sound right to you all, or is the dealer selling batteries?

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