Forum Discussion

voodoo101's avatar
voodoo101
Explorer
Apr 28, 2020

battery/meter electrical problem

I neglected my rv for the entire winter and am paying the price. My 4x6 volt flooded GC2 batteries are near dead. Today I was trouble shooting them to see if I could revive/charge them enough to get the RV to a shop to swap them. Two of them were very low, ~ 2.8 and 3.6 volts.

I connected them in series (bat 1 pos to bat 2 neg/grnd) and checked for their combined voltage and I get a 0 volt reading and a tone, like the one for continuity instead of the combined voltage. Reading from bat #1 neg to bat #2 pos. I have never had a tone from a DC voltage reading. Connecting the two meter probes gives 0 voltage but no tone.

The meter gives reliable readings for dc voltage on other sources. After separating the batteries, they read individual batteries properly again. I am not new to 6 volt batteries, but I feel like other times in life when I have been stumped by a simple problem until the obvious pops up.

So i am ready to be humiliated with the obvious. I am in AZ and it is too hot to spend the day out there. thanks, bill

On edit: Let me state my question more clearly. Why would two partially charged batteries in series give a zero voltage reading and even stranger, create a tone on a volt meter set at DC voltage?
  • theoldwizard1's avatar
    theoldwizard1
    Explorer II
    Apr 28, 2020
    If you have an old "dumb" charger, hook the pair (in series) up to it.

    You probably should bite the bullet and go buy 4 new batteries. They will never be the same.
  • K_Charles's avatar
    K_Charles
    Explorer
    Apr 28, 2020
    (bat 1 pos to bat 2 neg/grnd) does that mean you hooked the pos cable of one battery to the post of the other battery that was grounded? I hope not.
  • 2oldman's avatar
    2oldman
    Explorer II
    Apr 28, 2020
    I guess you have to drive the RV or you could just take the batteries, but I'm sure you've thought of that.
  • voodoo101's avatar
    voodoo101
    Explorer
    Apr 28, 2020
    K Charles wrote:
    (bat 1 pos to bat 2 neg/grnd) does that mean you hooked the pos cable of one battery to the post of the other battery that was grounded? I hope not.

    Of course I did. That is how you create a 12 volt battery from 2 6 volt batteries. Connect in series.
  • enblethen's avatar
    enblethen
    Nomad
    Apr 28, 2020
    I believe K Charles was trying to insure that you connected them correctly. Don't think he was trying to be smart a*s.
    What he was, I hope saying, was to verify battery connections. Positive of one battery to negative of the other. Negative of battery to ground, positive to other to positive of rig. Battery one positive to meter red, negative on battery two to black lead of meter.
  • time2roll's avatar
    time2roll
    Nomad
    Apr 28, 2020
    voodoo101 wrote:
    On edit: Let me state my question more clearly. Why would two partially charged batteries in series give a zero voltage reading and even stranger, create a tone on a volt meter set at DC voltage?
    batteries are telling you they are shot.

    Or could be the combination of sun, heat, frustration that has them connected wrong. Have you checked your voltmeter on something reliable like your tow vehicle battery?
  • wopachop's avatar
    wopachop
    Explorer
    Apr 28, 2020
    voodoo101 wrote:


    I connected them in series (bat 1 pos to bat 2 neg/grnd) and checked for their combined voltage and I get a 0 volt reading and a tone,
    I sometimes get a tone on my meter when reading DC. Its always because i accidentally have it set wrong. I have to click a button to switch between AC and DC.

    Hope this doesnt confuse things. Either your cable between batteries is not making a strong connection, or you wired it goofy.

    If i was to describe my (2) 6v batteries i would say BAT 1 is my positive source and BAT 2 is my NEG. Which means i would wire it backwards than how you describe it. BAT 1 neg post has a cable over to BAT 2 positive post.

    Make sure to dig the probe into the battery post. Maybe its just not making a good connection?

    Its weird about the tone youre hearing. I feel like that is the answer but its not hitting me yet. My meter will tone and show OL for open line when i screw up and dont have it set properly.
  • voodoo101's avatar
    voodoo101
    Explorer
    Apr 30, 2020
    Thanks to everyone for your thoughts. I installed my 4 GC2 6 volt system years ago and am confident in the connections. I am going to replace the batteries as soon as I can get them out. I am no longer able to lift 60# at arm's length and hard to ask for help with the current quarantine. I was hoping to get them working enough to move the Fiver to a battery shop. I still have more trouble shooting to figure why they died when on a maintenance charge from my solar system. And I double checked the meter settings. I am giving this a couple days to let my mind clear and will figure it out. Thanks again to all. Let's close the thread.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Apr 30, 2020
    You said you hooked Positive to Negative then measured from the other two positive and negative posts.. ARE YOU SURE you hooked positive to negative

    And are you sure the cable was good?

    First solution: Verify by the markings on the batteries.. Top post batteries come in 3 or more flavors

    One has the posts along one edge it comes in both a GC-2 and a GC-2-R (the R means positive and negative are reversed)

    One has them in the corners and again. there is an "R" version

    The last one they are center mounted. no "R" on this you simply turn it around

    But read the markings on the battery

    To test the jumper.> With the batteries connected positive to negative read from teh MOST negative post to the one with the jumper hooked to it. TOUCH the post. not the connector. Should be the same reading as if you did post to post on the single battery.

    I JUST did a repair job that called for 3 temporary jumper wires. 2 of them failed the above test .

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