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PlotCtr's avatar
PlotCtr
Explorer
May 11, 2014

Parasitic drain on 12 volt DC electric circuit

I have a drain on my 12volt system. I have found articles on how to find it. All of them tell you to pull fuses until your multi-meter shows a drop in amps. My problem is I have 12v DC circuit breakers instead of fuses. They are small round pegs about the size of a pencil eraser. They pop out when blown and you just push in to turn back on. However, I can not figure out how to turn them off to open the circuit to test for amp drop. Thanks for your help.

18 Replies

  • Thanks to all. First, I will try holding down the circuit breaker button to turn it off and check the load. If that doesn't work I'll open the panel and disconnect a wire to the breaker. When we get to a location with a Sears I'm going to look for one of those DC amp meters.

    This is a new problem that results in excessive drain over normal dry camping. We were doing fine for a week, the batteries were charging daily as we traveled and the drain by morning was nominal. Suddenly one morning the drain was excessive, so probably a short.

    We have a 2013 Tiffin Allegro CA 32. The coach has both 12v and 120 V panels. Both are protected with circuit breakers. The chassis has its own panel which uses fuses.
  • I tested my system and found the parasitic draw was displayed at 0.10 a. I didn't really care where specifically they came from, but just what that amount was. I did install a battery disconnect switch.
  • When I had the same situation it turned out that one of the batteries had a bad cell and was drawing down both batteries slowly. Removed the bad battery and no more problems.
    Don
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    PlotCtr wrote:
    I have a drain on my 12volt system. I have found articles on how to find it. All of them tell you to pull fuses until your multi-meter shows a drop in amps. My problem is I have 12v DC circuit breakers instead of fuses. They are small round pegs about the size of a pencil eraser. They pop out when blown and you just push in to turn back on. However, I can not figure out how to turn them off to open the circuit to test for amp drop. Thanks for your help.


    How many are there?

    Here is how to do it

    Put your ammeter in line and note the drain.

    now, one at a time PUSH those breakers, like you are trying to reset them....

    As a safety feature (Some 1-D-10-T types try to "Lock them down" so they do not trip so as a safety feature) When pushed they open.

    When the meter reading goes down.. That's the circuit. (there may be more than one)
  • RoyB's avatar
    RoyB
    Explorer II
    I'm curious what your RV unit is... I've never heard of one with only 12VDC circuit breakers. Most I have been around have a power distribution panel which has 120VAC Circuit breakers on one side and 12VDC fuses on the other.

    Would love to know what year and model RV you have...

    Roy Ken
  • Almot's avatar
    Almot
    Explorer III
    People mean all kind of loads when talking about parasitic drain. There is no such thing unless something is shorted. If it's under 2A, this is control circuit of LP fridge and radio clock and LP detector (and possibly CO detector though they are often on AA batteries). If there is a lot more current, then something is running or there is a short. Like people said, if you want to stop all drains, ex. in storage - disconnect the battery.
  • Do you have a DC amp meter?

    If you do, you can measure the DC load by removing the negative wire, then connecting the - cable to one lead and the other lead directly to the battery. Say it gives you a 0.8 amp load, and you hear the CO meter and propane detector beeping that they just got back power. You know that both of those had power restored, and might be the loads you are looking for. By shutting off the propane detector, your load might go down to say 0.4 amps, indicating you found one load, the other probably being the CO meter that can not be shut off (for safety reasons).

    If the load is over 5 amps, then removing one circuit breaker at a time can help locate the problem. Because you can not remove the fuse, like a typical load panel, you might need to remove one wire from a circuit breaker at a time until the load goes away.

    If your "Problem" is that while not plugged in your 220 amp hour battery is totally dead in about 4 days, then the "Problem" is the CO and Propane detectors together use that much power, and it is really not a problem that can be fixed. Better to just add a 120 watt solar panel, or keep it plugged into shore power, and then you will keep the battery full that way, and will solve the problem.

    Sears has a clamp on DC amp meter. With it, you can clamp it around one wire at a time, and see about how many amps are being used by that wire at one time. It is a easy way to measure the DC amps. it is about $80 - $100.

    Good luck,

    Fred.
  • Just remove the ground cable from the battery when not in use. No more parasitic drains.

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