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CavemanCharlie's avatar
CavemanCharlie
Explorer III
Dec 08, 2015

Battery Question

I converted my TT to 2-6 volt flooded golf cart batteries and a upgraded converter from Best Converters. This was about 2 years ago. I dry camp once and awhile but, not to often. I have been very happy with this set up.

Last fall on my last trip of the season I was going to dry camp and when I got to the park I was low on voltage. I was shocked and a little worried. When I got home and put the TT in the shed for the winter I cleaned the posts and added water. The water level was not below the cells though it was a little low. I figured I must have made a mistake and not had the TT plugged in all the way before I left for my final trip of the season and that is why I had low voltage that time.

I've been keeping a eye on the voltage all winter as I usually do. I don't leave the converter on. It doesn't like to go into float mode. So, I flip it on once every few weeks to charge things up hen turn it back off.

I charged everything up about 3 weeks ago when it was 15 degrees f outside then shut the converter down . The voltage hovered around 12.9-13 volts for the first 2 weeks. This week the temp went up to 40 degrees f outside.

My battery voltage is now 13.9 volts :E with the converter off and no load on the batteries.

Is this normal ? I can't seem to find a answer on the internet.

(I wonder if the cheap volt meter that I have plugged into the cigarette outlet inside the TT is acting up ? )

Thank you for any responses you can give.
Seeking Advice
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Dec 09, 2015
    When you first shut off the charger the batteries retain both a Charge and what we call a "Surface Charge" They can indeed test well over 12.6 Come back in an hour or two and meter them again.
  • CavemanCharlie's avatar
    CavemanCharlie
    Explorer III
    Dec 09, 2015
    Matt_Colie wrote:
    I did a lot of boat work before the depression and I often saw this sort of thing.

    Assuming you have a good meter for starters, mine are. It is not uncommon to see a fully charged battery at rest sitting at 13V+. With even the slightest load, the terminal will drop into the high 12s instantly. Turn on a light and they will be a 12.6 in moments. I was told by my "battery guy" (an engineer with Decca) that this is an artifact of "surface charging" where the electrolyte nearest the plates has developed a higher density and has not been redistributed yet. That redistribution can take quite a while.

    The condition does not represent or cause a problem.

    Matt


    Thanks. Sounds like a plan. My lights are all LED and draw very little currant. I will kick the furnace on for a couple of minutes and see what the reading is after that.

    I also think I will un-plug my volt meter first and bring it in the house to warm up .
  • Matt_Colie's avatar
    Matt_Colie
    Explorer II
    Dec 09, 2015
    I did a lot of boat work before the depression and I often saw this sort of thing.

    Assuming you have a good meter for starters, mine are. It is not uncommon to see a fully charged battery at rest sitting at 13V+. With even the slightest load, the terminal will drop into the high 12s instantly. Turn on a light and they will be a 12.6 in moments. I was told by my "battery guy" (an engineer with Decca) that this is an artifact of "surface charging" where the electrolyte nearest the plates has developed a higher density and has not been redistributed yet. That redistribution can take quite a while.

    The condition does not represent or cause a problem.

    Matt
  • RoyB's avatar
    RoyB
    Explorer II
    Dec 09, 2015
    Your batteries should read 12.6-7VDC when resting if they are fully charged. The 13.6VDC is coming form some sort of charging event.

    When i have my batteries connected to the working converter/charger they normally read around 13.6VDC. When I shut down the converter/charger I have wait several minutes for the batteries to slowly taper down to the 12.6-7 VDC reading which is what I call resting DC voltage.

    This is a handy chart showing the DC VOLTS verses the approximate charge status.



    Roy Ken
  • eb145's avatar
    eb145
    Explorer II
    Dec 09, 2015
    Any chance someone stuck a small solar panel on your trailer and wired it in when you weren't looking? :)
  • westend's avatar
    westend
    Explorer
    Dec 09, 2015
    Buy a hand held meter and a hydrometer. They will both come in handy when working with batteries and your RV. I'd bet that your voltage gauge is now going South.
  • Canadian_Rainbi's avatar
    Canadian_Rainbi
    Explorer
    Dec 09, 2015
    rjxj wrote:
    Double check with a different meter. My handheld acts crazy when the internal battery is low. The bottom line with knowing where the batteries stand is dipping them to check SG. Only way they could be at 13.9 is with the converter on.



    X2 on the XG Or a bad voltmeter (unlikely).
  • azrving's avatar
    azrving
    Explorer
    Dec 09, 2015
    Double check with a different meter. My handheld acts crazy when the internal battery is low. The bottom line with knowing where the batteries stand is dipping them to check SG. Only way they could be at 13.9 is with the converter on.
  • enblethen's avatar
    enblethen
    Nomad
    Dec 09, 2015
    Even though I have one of the dash plug-in units, I do not trust it. it is good for reference.

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