Forum Discussion

desertratt1's avatar
desertratt1
Explorer
Sep 12, 2020

group 65 vs group 31 battery for mtr hm maxx brand

I have a 1997 Beaver Monterey it has been stored for a few years in RV park in white mtns az. I am up here to try get motorhome back to Tucson and looks like all the batteries are shot. I have two napa 7236 batteries group 31 and have threaded post. I have 4 6 volt orielly batteries gs100tj same as a gs2 they say 115 min on them. I have had excellent luck with the maxx batteries from walmart got 10 years out of the pair on my dodge cummins. I called the local walmart they havee a group 65 not a group 31 like the napa battery and it has regular post not threaded post. I was thinking of just getting post adapters and buying these as they have 3 year full replacement warranty i called napa they have 18 mo and some only have 12 mo. Plus walmarts are everywhere. Same with the GS2 they are 98.00 oh and so is group 65battery 98.00 . Any advice or thoughts on this ?

Thanks in advance..
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Sep 16, 2020
    Though the group size is interesting and does indicate a lot of things Lead Acid batteries come in several "Flavors" as it were.
    For example
    Flooded wet (You add Distilled water from time to time)
    Maintenance free (No adding anything)
    AGM. (Likewise plus some other advantages)

    None of that matters to this post

    Another division
    Starting
    MARINE/deep cycle or MARINE/rv
    DEEP CYCLE

    Pay attention to case in this part (UPPER/lower)
    Starting batteries are designed to put out a lot of current but not all that any amp hours. They like to be 80% full or better..

    MARING/deep cycle or rv are starting batteries but with a nod to Deep cycle, they should be kept above about 75% State of charge

    DEEP CYCLE can go down to 50 ... Some lower

    THe GC-2's are likely DEEP CYCLE (GC = Golf Car)
    THe rest are not.
  • jkwilson's avatar
    jkwilson
    Explorer III
    Sep 16, 2020
    Those group 31s are commercial starting batteries. They are readily available for a reasonable price at virtually any auto parts place. Their cranking power will put a group 65 to shame.
  • desertratt1's avatar
    desertratt1
    Explorer
    Sep 16, 2020
    i want to thank everyone for their input i went with the group 31 die hard commercial batteries as walmart was out of batteries so just decided i needed to move forward.


    rick
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Sep 12, 2020
    Group 65 is automatically an engine starting battery. First consideration: Engine type Diesel need glow plug then engine cranking ability. 2nd Life in Minneaota is polar opposite to say sothern Texas.

    The 65 is a low profile battery like a group 78. Low and wide. I would recommend time with a tape measure and then make sure the battery post polarity and location agrees with the length and orientation of your battery cables.
  • MrWizard's avatar
    MrWizard
    Moderator
    Sep 12, 2020
    I have used screw in adapters
    I have some in my electrical tool bag right now
    They work fine,
  • time2roll's avatar
    time2roll
    Nomad
    Sep 12, 2020
    Group 65 is a fairly common start battery. Group 31 is more often deep cycle.

    So yes get a 65 for the chassis and a 31 for the house. Adapters are fine if needed.
  • Birdnst's avatar
    Birdnst
    Explorer
    Sep 12, 2020
    Don't have information handy, however look up group sizes due to the fact that is the physical dimensions of the battery. LxWxH
  • Lwiddis's avatar
    Lwiddis
    Explorer II
    Sep 12, 2020
    After a few years of storage it’s not a mystery why your batteries are shot. Not clear whether you are buying house batteries, engine starting batteries or both. They are different. Are the MH’s tires safe?

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