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oldtrojan66's avatar
oldtrojan66
Explorer
Jan 18, 2015

6 volt vs 12 volt charging

I just installed two Trojan T105 6 volt batteries in my fifth wheel. I hooked them up in series to get 12 volt output. I had two gp 24 12 volt batteries before hooked up in parallel. When charging (converter on shore power 30 amp) I typically read 13.1 to 13.4 Now I read 12.5 and 12.4 a little later on my digital gauge. Is something wrong, or do 12 volt and 6 volt batteries charge at different rates from the same converter? Thanks in advance for your help.
  • 2oldman's avatar
    2oldman
    Explorer II
    Jan 18, 2015
    JamesJudasPriest wrote:
    check that you didn`t connect the batteries backwards, which will cause the converter output fuse to blow.
    Agreed.
  • JamesJudasPries's avatar
    JamesJudasPries
    Explorer
    Jan 18, 2015
    even when your converter is putting out max power (dead batteries) the voltage should really never go below 12.6, and it should rise slightly and continuously above that in minutes, until you reach 13.6, or more. check that you didn`t connect the batteries backwards, which will cause the converter output fuse to blow. The dropping voltage you describe sounds like the converter is providing no power at all.
  • ScottG's avatar
    ScottG
    Nomad
    Jan 18, 2015
    No, your voltages s/b about he same as the 12V's so something is wrong. I would check the individual voltages of your new batteries.
    A couple of years ago I bough two new batts and one was shorted internally right off the shelf.

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