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wealthwise's avatar
wealthwise
Explorer
Aug 28, 2013

Another Battery Question

Sorry I have to start a new thread but I didn't get an answer to my last post, so here goes.

One thing I'm trying to figure out is which battery is for what? Are they two front batteries connected to each other for everything but the starter and if so, how do they get recharged, by electric hookup, in other words they are both house batteries? Is that sealed battery in the rear the starter battery? Is that how it works with pushers? When I disconnect it the starter does not engage, so then I guess by brilliant deduction that means that the two batteries in the front are house batteries and provide power to the jacks and slide. That's got to be how it is, I can't imagine any other explanation? So if I wanted to test the Alternator does it work the same way with any car, just disconnect the negative cable from the rear battery and if doesn't stall it's fine? I did that and it didn't stall. I hope that's how to test it. Because I haven't located the alternator so far.
Thanks

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  • westend's avatar
    westend
    Explorer
    Aug 28, 2013
    Measure the battery at rest, then measure across the posts with the alternator running. A fully charged battery without a surface charge should measure 12.6V. Measuring across the battery posts with engine running should measure 13.5-14.5 V.

    If you have two batteries connected in parallel and only one is charging, you have a wiring problem or a bad battery.
  • wealthwise's avatar
    wealthwise
    Explorer
    Aug 28, 2013
    I understand all that, but does the alternator charge those two front batteries or just the rear starter one? I did test the two in in front, but the one that's at 14 is petty much around 14 either way.
  • azrving's avatar
    azrving
    Explorer
    Aug 28, 2013
    Like rjsfishin said. Never check the alternator by removing the cable. Slap whoever told you that. Is the belt tight or even on the engine? Is the fusible link OK? Check all the terminals and connectors before replacing anything. Remove the NEGATIVE cable from the battery when working on any cables or connectors at the alternator. DONT let the wrench arch near the battery or you risk having a bomb go off in your face. The battery produces hydrogen gas when charging or discharging. If its charging it should read between 13.7 and 14.2 volts when running.
  • wealthwise's avatar
    wealthwise
    Explorer
    Aug 28, 2013
    MrWizard wrote:
    use the meter, check volts on each battery, with engine off

    start engine and check volts on each battery again

    voltage should be above 13 aka 13.xx to charge the batteries

    batteries getting voltage are being charged

    yes autozone will check your batteries, they check mine, they like selling new batteries


    Did as you advised and the only battery that stayed the same was the new one that's in front connected to the other one, by the way the rear one is a Interstate High Cell or something like that, so what do I do about the battery that remains the same?
    Thanks
  • wealthwise's avatar
    wealthwise
    Explorer
    Aug 28, 2013
    MrWizard wrote:


    yes autozone will check your batteries, they check mine, they like selling new batteries


    Do they check alternators on RVs?
  • MrWizard's avatar
    MrWizard
    Moderator
    Aug 28, 2013
    use the meter, check volts on each battery, with engine off

    start engine and check volts on each battery again

    voltage should be above 13 aka 13.xx to charge the batteries

    batteries getting voltage are being charged

    yes autozone will check your batteries, they check mine, they like selling new batteries
  • wealthwise's avatar
    wealthwise
    Explorer
    Aug 28, 2013
    Ok I have a multimeter but I don't think it checks amperage only volts, normally for my mini van I would just go to Autozone, but I don't think they will check a 32 foot class A, would they?
  • RJsfishin's avatar
    RJsfishin
    Explorer
    Aug 28, 2013
    To test an alternator, you check the charging voltage and amperage.

    Disconnecting a battery cable while engine is running, is living dangerously and can be fatal to an alternator.
  • samsiuhong's avatar
    samsiuhong
    Explorer
    Aug 28, 2013
    To test an alternator, you have to disconnect the negative cable from the battery and if doesn't stall it is fine.

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