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Dennis1957's avatar
Dennis1957
Explorer
Jul 17, 2013

Battery Draw, "HELP"

I have a button I push when putting the class C in storage. When I push that button it disconnects the 12 volt power from the coach. I have verified this by checking each fuse at the panel for a power draw. So the switch is working fine. BUT, I'm still experiencing a battery draw and can't find where it is coming from. When checking the negative side of the terminal with a volt meter it shows 12.33 volts. I've seen on the web that is how you check for a draw. But when I use a test lamp it does not light, so do I really have a draw? We're going on vacation soon and want to make sure we don't have a problem.

8 Replies

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  • Shadow_Catcher's avatar
    Shadow_Catcher
    Explorer
    Jul 17, 2013
    The 12.33 volts is the battery voltage and as indicated you need a multimeter and to use it you have to disconnect the battery terminal and measure between it and the battery. Not mentioned is that batteries self discharge at a rate between 3 and 20% per month depending on battery type. This is one of the reasons I chose an AGM battery, slow self discharge.
  • hershey's avatar
    hershey
    Explorer
    Jul 17, 2013
    Like said: "disconnect the battery". I know that the simple act of using the rocker switch is easier and really pretty darn neat....but it would be even neater if it really worked as expected. Save yourself a lot of headaches, just disconnect the negative cable.
  • Old-Biscuit's avatar
    Old-Biscuit
    Explorer III
    Jul 17, 2013
    Hardwired smoke detectors, LP detectors, CO detectors all come directly from battery and will have continuous draw on batteries.
  • Sloop_Smitten's avatar
    Sloop_Smitten
    Explorer
    Jul 17, 2013
    You do not check for battery draw (current) by measuring the battery voltage. You need to use a multimeter to measure amps. If you disconnect the battery ground cable and attach one lead of the meter to the ground terminal of the battery and the other to the ground cable you can verify how many milliamps are being drawn when the switch is off. Make sure you have the meter set to read current and not voltage or resistance. You can then pull your DC fuses one at a time and check for any variance to identify what is causing the current draw. If none of the fuses make a difference then you probably have something hard wired to the system like a propane detector or radio that is using current to maintain memory. The radio may have its own inline fuse which is not located in the fuse panel. All reading 12.33 volts tells you is that you have a patially dischargred battery which can be caused by current draw or having never been fully charged.
  • Wheel_Estate's avatar
    Wheel_Estate
    Explorer
    Jul 17, 2013
    my jacks are wired in ahead of the battery disconnect...try running stuff to see....your inverter is a possability
  • lhenry8113's avatar
    lhenry8113
    Explorer
    Jul 17, 2013
    I just had a situation with my Diesel truck batteries and found it was not the batteries but a bad Diode in the engine generator. When the motor was running it was charging the correct amps to the batteries---when the motor was not running is was discharging 3.8 amps. Camp back to the bad Diode--replaced the Gen. and no more problems--Lars

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