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Thread: Battery drain issue 2 amps key off

  1. #1
    boostaholic
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    Battery drain issue 2 amps key off

    Been trying like crazy (12 hours this week) to diagnose the battery drain key off with the lancer.
    I have it to the point where I disconnect the smec and it slowly stops the draw from 2 amp down to zero. If I unplug the main positive connector that goes to the fusible links it instantly drops to 0 amp draw.
    I have the bulkhead disconnected so it's not on the inside of the car. With all the sensors, alternator, relays, starter, and any other connector I can find the draw is still 2 amps till I disconnect the smec or that main power cable. I have tried three smecs and all give the same 2 amp draw. When this first came about I tried removing one fuse at a time and that made no difference. Then Naj from the other forum suggested the bulk head disconnect.

    This is a 1988 dodge lancer shelby 2.2 manual ac car

    Any other ideas out there?

  2. #2
    turbo addict
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    Re: Battery drain issue 2 amps key off

    my vote is to take a DC clamp-on ammeter and put it on every fusible link one at a time to find the draw. would take 30 seconds. $40 gets you one...

    I almost wish I had a parasitic draw so I could try this

  3. #3
    boostaholic
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    Re: Battery drain issue 2 amps key off

    I would not wish this parasitic drain on anyone...well almost no one.

    These clamps will they not be influenced by the other wire carrying current?

  4. #4
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    Re: Battery drain issue 2 amps key off


  5. #5
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    Re: Battery drain issue 2 amps key off

    Quote Originally Posted by going4speed View Post
    $40 will get you one that will do the job..I bought this one and it seems pretty good

    http://www.ebay.com/itm/181390405486...%3AMEBIDX%3AIT

    2 amps is a huge signal and any clamp meter will detect that with ease.

    to use the clamp ammeter, you put one wire at a time through the clamp. its not affected by wires outside the clamp.

  6. #6
    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Battery drain issue 2 amps key off

    make sure its a DC clamp on ammeter.... AC ones are more common and will not work for this.

    also... leave the SMEC connected and disconnect each relay on the inner fender one by one and see if it helps.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  7. #7
    boostaholic
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    Re: Battery drain issue 2 amps key off

    Got a DC clamp coming. Bought the cheap one as suggested and much appreciate the info.

    I have removed every relay, fuse, connector and plug on this car one by one and all at once.

  8. #8
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    Re: Battery drain issue 2 amps key off

    Quote Originally Posted by going4speed View Post
    Got a DC clamp coming. Bought the cheap one as suggested and much appreciate the info.

    I have removed every relay, fuse, connector and plug on this car one by one and all at once.
    You know its weird I bought that DC clamp meter for something totally different and only now did I realize how useful it would be for automotive stuff....I mean you could really nail a parasitic draw no problem with it.

    You could also see exactly how much current the battery is being charged (or discharged) with at any time. Cranking amps. Overall current draw with all accessories turned on...could be interesting

  9. #9
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    Re: Battery drain issue 2 amps key off

    wow! Yea I hope this works. I'm a ME so I can hold my own at electrical but this one is kicking my butt!

  10. #10
    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Battery drain issue 2 amps key off

    I figured you might have..... seeing how bad this is....

    You may have to unwrap the harness and see if there are wires melted together.

    I use an old polyester blanket and spread it out on the floor in the living room when I have an unknown harness.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  11. #11
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    Re: Battery drain issue 2 amps key off

    okay I tried that meter on my jeep

    I clamped it on the battery positive cable...showed 2 amps with the interior lights on. With the engine idling showed about 8 amps charging the battery. interesting..I'm sure this will come in handy at some point.

    If you're measuring less than 300ma I'd make sure to carefully observe what the reading is immediately before clamping on to a wire. Use relative mode to make sure you get a solid zero. Seems like it was bouncing around from zero to 0.25A depending on how I had the meter oriented and I think its a little sensitive to metal objects outside the clamp. Its the first time I've used it though so I bet with some experimenting its lower range can be improved. I didnt mess around with it more than a couple minutes to see what might make it better or worse. But I think measuring down to 10ma might be tricky in an engine compartment.

    If you are looking for 2 amps that should be no problem.

  12. #12
    boostaholic
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    Re: Battery drain issue 2 amps key off

    Cool thanks for the experiment and results.

    If I get down to 0.25A draw I'll be very happy. I believe 0.25A to be sustainable for a car.

  13. #13
    The moderately moderate moderator Turbo Mopar Staff
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    Re: Battery drain issue 2 amps key off

    It's a little high, but for a daily driver it shouldn't kill the battery.
    Bryan
    86 GLHS #161, 2016 Impala
    SDAC National Member, SDAC Buckeye Chapter Member

    A man has got to know his limitations.....

  14. #14
    boostaholic
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    Re: Battery drain issue 2 amps key off

    How low should the key off draw be?

  15. #15
    The moderately moderate moderator Turbo Mopar Staff
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    Re: Battery drain issue 2 amps key off

    For one of these cars, no more than 70ma. Should be less than 50ma after all the modules have shut down. This is all lights off and doors closed.
    Bryan
    86 GLHS #161, 2016 Impala
    SDAC National Member, SDAC Buckeye Chapter Member

    A man has got to know his limitations.....

  16. #16
    boostaholic
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    Re: Battery drain issue 2 amps key off

    Wow! Yea 2 amps is a tad more than 70ma

  17. #17
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    Re: Battery drain issue 2 amps key off

    Got the dc clamp meter. Verified amp draw today with regular meter at 1.9 amps. Took out the clamp meter and with the car hooked up normally to the battery terminal with a verified zero amp draw on the regular meter so I know the car is hookup up. With the clamp meter hooked up and around the positive terminal zero amp draw. Okay must be doing something wrong. Check across the negative wire...zero amp draw. Next I put it around the positive fan wire and got 1 amp. Unplugged the fan plug and still get one amp on the positive wire. That's not right. Cant be an inductance in that wire with the plug undone. Took the meter to the gti with it running and see 13 amps on the positive wire from the battery.

    No way this could be used to diagnose a short. I put it around the coil positive wire and get 1 amp. Negative coil wire 1 amp. AC clutch wires one amp each.

    Quote Originally Posted by acannell View Post
    okay I tried that meter on my jeep

    I clamped it on the battery positive cable...showed 2 amps with the interior lights on. With the engine idling showed about 8 amps charging the battery. interesting..I'm sure this will come in handy at some point.

    If you're measuring less than 300ma I'd make sure to carefully observe what the reading is immediately before clamping on to a wire. Use relative mode to make sure you get a solid zero. Seems like it was bouncing around from zero to 0.25A depending on how I had the meter oriented and I think its a little sensitive to metal objects outside the clamp. Its the first time I've used it though so I bet with some experimenting its lower range can be improved. I didnt mess around with it more than a couple minutes to see what might make it better or worse. But I think measuring down to 10ma might be tricky in an engine compartment.

    If you are looking for 2 amps that should be no problem.
    - - - Updated - - -

    Oh and another thing. With the meter hooked up when i first connect the battery the amp draw is low near zero and slowly creeps up to 1.9 amps. If this is a short it should shoot straight to 1.9 amps right?

  18. #18
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    Re: Battery drain issue 2 amps key off

    Quote Originally Posted by going4speed View Post
    Got the dc clamp meter. Verified amp draw today with regular meter at 1.9 amps. Took out the clamp meter and with the car hooked up normally to the battery terminal with a verified zero amp draw on the regular meter so I know the car is hookup up. With the clamp meter hooked up and around the positive terminal zero amp draw. Okay must be doing something wrong. Check across the negative wire...zero amp draw. Next I put it around the positive fan wire and got 1 amp. Unplugged the fan plug and still get one amp on the positive wire. That's not right. Cant be an inductance in that wire with the plug undone. Took the meter to the gti with it running and see 13 amps on the positive wire from the battery.

    No way this could be used to diagnose a short. I put it around the coil positive wire and get 1 amp. Negative coil wire 1 amp. AC clutch wires one amp each.



    - - - Updated - - -

    Oh and another thing. With the meter hooked up when i first connect the battery the amp draw is low near zero and slowly creeps up to 1.9 amps. If this is a short it should shoot straight to 1.9 amps right?
    You have it in DC mode right? On the 40A range?

    If you just hold the meter in your hand with nothing going through the clamp, what reading do you get?

    Look at it this way, if the clamp meter can measure current, then it can be used to diagnose a short. The same way I did measurements on my jeep. So it must be the way you are using it. You're only passing one wire through it at a time, right?

    Snap a pic of how you're using it.

    - - - Updated - - -

    Oh and another thing. With the meter hooked up when i first connect the battery the amp draw is low near zero and slowly creeps up to 1.9 amps. If this is a short it should shoot straight to 1.9 amps right?
    Can't characterize the fault before we know whats causing it. A "short" would be vaporizing things anyways. What you have is a current draw thats larger than you'd like. Thats all we know.

  19. #19
    boostaholic
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    Re: Battery drain issue 2 amps key off

    Meter was in DC mode one wire at a time. With the meter just sitting there it had 0.01 or 0.02 after hitting rel.

    What about the measurement of 1 amp with the plug disconnected like the fan wiring? Does this electrically make sense somehow?

    If I put this clamp around the negative cable it should have measured the current right? It just sat at 0.01.

  20. #20
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    Re: Battery drain issue 2 amps key off

    Quote Originally Posted by going4speed View Post
    Meter was in DC mode one wire at a time. With the meter just sitting there it had 0.01 or 0.02 after hitting rel.

    What about the measurement of 1 amp with the plug disconnected like the fan wiring? Does this electrically make sense somehow?
    What about before hitting rel? If you just turn the meter on, and its in DC mode and 40A range, with no wires, and without hitting rel, is it showing 1 amp?

    Mine shows between 0.01A and 0.35A depending on how I orient it. Laying on the countertop, 0.35A. Holding in my hand, about 0.15A. This is without using REL.

    Play around with it until it makes sense what its doing. Sometimes when I hit rel the display doesnt go to zero. I think thats because the "noise" changes when I go to hit the button. Clamp-type DC meters are very sensitive and you need to make sure to zero them with REL right before you take the measurement, in the exact same orientation and with the wire going through as centered as possible.

    You measured 1 amp on a wire that goes to the fan motor, with that wire unplugged from the vehicle side? No that doesnt make sense. Thats either the meter being sensitive and needing to be REL'd to zero beforehand, or something wrong with the meter. Keep playing with measurements until it makes sense. You'll get it. I know from using it on my jeep that it could definitely be used to find a > 0.5A current draw no problem. A tenth of that might be tricky. But 2 amps should be very easy. Just make sure you zero it effectively.

    Try measuring a circuit you know you can control. Like the fusible link which leads to the headlights or radio or something you can definitely turn on and off. Repeat the measurements until you figure out how it needs to go to be consistent. Then jump to the other fusible links until you find the culprit.

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