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Gjac's avatar
Gjac
Explorer III
Sep 12, 2020

Battery observations

I have 2 6V Sams Club GC batteries in my MH that are 13 years old. I went to charge them a month ago with my "smart charger" and it would not charge due to a sulfated cell(F2). So I figured it was time for new batteries. After multiple attempts I decided to try my old Magnetech 950 "dumb charger", after several hours with a 5 amp 13.2 v charge I was then able to use my 40 amp B&D charger again and it took a charge until it said FUL. I then continued to charge with the Magnatech for several more days prior to a camping trip to NH. I was thinking after 13 years these batteries lost a lot of capacity and figured I would have to use the genset to recharge during the week, I only dry camp. I don't watch TV, no internet or cell phone service where we camp so just lights, WP, refer and WH usage. To my amazement I lasted a week without recharging and was at 50% SOC, which was what I always saw when the batteries were newer. Usually I recharge over night with the B&D but the 5 hr drive home seemed to fully charge the batteries. They are still at 12.6 volts after sitting for a week with no charge (I don't keep a trickle charger on them just recharge when they get to 80% SOC.) So I will see if they survive the winter with no charge for another camping season. I realize most batteries die from sulfation(under charging) but I don't hear much discussion about constant or float charging and plate sheading.
  • BFL13's avatar
    BFL13
    Explorer II
    Sep 13, 2020
    The "pulse" desulphation (frequency of, that broke down the sulphate) was pretty much found to be bogus 10 or 15 years ago. Suprised people still doing that. Vector/B&D had that mode back then and I used to do it. Turned out not to be any use.

    However the last set of chargers before they went tits up also had an Equalize mode which used high voltage. That does work, and I still use that with mine (VEC1093DBD). You can also use that method with a PowerMax LK model or with some other chargers, inverter/chargers, and solar controllers.

    On floating 6s, there was a school of thoght back then that 6s should not be floated. Xantrex had a choice in their converter to make the 3rd stage optional for that reason.

    The OP may have discovered that was valid- not enough evidence to confirm. It was to do with high SG electrolyte vs low SG and the purpose of the battery for deep cycling (high SG) or for "stand by" use (low SG)

    On Mex's advice re short gen times, 50-80s, and high amp charging , I am still with the program! :)
  • MEXICOWANDERER's avatar
    MEXICOWANDERER
    Explorer
    Sep 12, 2020
    Interest in flooded batteries has waned to the vanishing point.
    Years ago I furnished a lot of information to this site which was then proprietary.

    Included was a rather concise interpretation of using an adjustable voltage but constant potential charger called a Megawatt. They are 29 or 36 amp dependent on model.

    Times change. And now there is little interest in flooded batteries, minimum charge time, and maintaining batteries for the most longevity.

    I then opened up the Megawatt and upgraded the weakest links inside, added an external voltage control and finished up by redesigning the unit into a 56 amp unit.
  • Gjac's avatar
    Gjac
    Explorer III
    Sep 12, 2020
    ajriding wrote:
    13 years is impressive and sounds like you do not maintain them as well as you should.
    6-7 yrs is a long batt lifespan.

    Yes, do keep a trickle charger on them over the winter.

    I have a little device called a "de-sulphator" or something. Plugs into any DC outlet in the car, RV and desulphates the batteries. I can't substantiate if it works or not or what it is doing. It is supposed to keep the crud off the plates, i think it sends a little pulse to the battery to "shake" or "vibrate" or in some way remove the scale. It has been years so I forgot all the claims and details.

    I run it in the truck every month or so and in the Rv, but not constantly.

    It only works when batt is at full charge (or being charged, so over 13v)

    I thought I would throw this tidbit in..
    My reason for not keeping a trickle charge on them constantly or over winter is I think the more you charge them the more you wear the plates down. Again I have not heard much discussion about that just MHO based on my experience. They have only been discharged once below 50 % but in general the deepest discharges are between 50-60% SOC. Yes I run the desulphater on mine also and on occasion and I also equalize.
  • jdc1's avatar
    jdc1
    Explorer II
    Sep 12, 2020
    Stick a solar charger on them and they may last another 10 years.
  • ajriding's avatar
    ajriding
    Explorer II
    Sep 12, 2020
    13 years is impressive and sounds like you do not maintain them as well as you should.
    6-7 yrs is a long batt lifespan.

    Yes, do keep a trickle charger on them over the winter.

    I have a little device called a "de-sulphator" or something. Plugs into any DC outlet in the car, RV and desulphates the batteries. I can't substantiate if it works or not or what it is doing. It is supposed to keep the crud off the plates, i think it sends a little pulse to the battery to "shake" or "vibrate" or in some way remove the scale. It has been years so I forgot all the claims and details.

    I run it in the truck every month or so and in the Rv, but not constantly.

    It only works when batt is at full charge (or being charged, so over 13v)

    I thought I would throw this tidbit in..
  • 2oldman's avatar
    2oldman
    Explorer II
    Sep 12, 2020
    Assuming no inverter or large draws, you should be ok, but it's likely batteries that old would not support big loads.

    This is a typical situation where many people eschew 6v batteries because if one fails you're sol. And yes, it's quite likely one of your 13yo batteries will fail before the other one, which is not far behind.

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