Forum Discussion

SHRED's avatar
SHRED
Explorer
Aug 01, 2021

Parasitic current draw on tow vehicle

My 2002 Honda CRV seems to lose its battery charge if it sits for a couple of days.
The battery has tested good at both NAPA and at Autozone.

I tried testing for draw with my cheap VOM by undoing the ground and running it in series on the 10A meter circuit, but it registered zero which isn't accurate since it draws some power for the clock, etc... I tried turning on the headlights and an interior light, I touched the VOM lead, and nothing. Nothing lit up. Is my VOM bad? It does measure voltage accurately however.

This is frustrating. Looks like I will need to take it in.
Is the allowable amp draw about 0.3 amps?

thanks

19 Replies

  • 2oldman wrote:
    How old is the battery?


    4 months old.
  • SHRED wrote:
    time2roll wrote:
    Check the 10a fuse in the meter.
    The VOM still reads voltage.
    Would that still be possible with a blown fuse?
    Yes
  • SHRED wrote:
    Any recommendations for a quality VOM? I'm tired of cheap junky ones.


    It isn't your cheap junky meter.

    It is how you are using it.

    10A setting you must use the input marked 10A.

    On 10A setting you will have a very low current resolution of .1A at a time which will not reveal very low current draws.

    Your DVM should have a MA (Milliamp) setting (may look like 1000 (1000 is 1A), 100, 10) which has a higher resolution. That setting will use your normal DVM "Volt/resistance" input lead.

    Choose the highest range on the MA setting then switch down..

    Have to very careful when using the MA setting as it is to smoke the meter..
  • time2roll wrote:
    Check the 10a fuse in the meter.


    The VOM still reads voltage.
    Would that still be possible with a blown fuse?
  • Any recommendations for a quality VOM? I'm tired of cheap junky ones.
  • I recently viewed several informative YouTube videos on finding parasitic draws on both trucks and cars. They showed step by step troubleshooting method. Maybe you can find a video for your make and model.
  • FYI Once you disconnect and reconnect the battery electrical resets may occur and you no longer have the drain perhaps until driving and turning off the car. That is just one reason why a clampon ammeter is so useful.

    Sounds like you meter is not working.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,292 PostsLatest Activity: Jul 31, 2025