Amp Draw when off

Discussion in 'Technical' started by smegnl, Jun 8, 2021.

  1. smegnl

    smegnl Roger Saffle Supporting Member

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    My car has a .005A (5mAmp) draw when off. It is on one of the fused wires going into the cab. If I take off wire A and leave on B, it goes to 0Amp.
    My question is this an issue? I know on modern cars there is as draw when off. But I would think a Maverick would be 0.
    I think its killing my battery. I dont start it more then once a month, but I always seem to be having a low battery.
     
  2. mojo

    mojo "Everett"- Senior Citizen Supporting Member

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    I wouldn't think that's enough to have low batt. starting once a month. Is the charging sys. putting out 14 or so volts?
    I would think my stero radio memory draws somewhere in that area and I never have a problem.
     
  3. yellow75

    yellow75 MCCI Oregon State Rep Supporting Member

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    Add a disconnect switch at the battery and turn it off when the car is in hibernation , like mojo says stereo will drain battery . Just starting the car once a month or so is not giving the battery enough time to charge
     
  4. Krazy Comet

    Krazy Comet Tom Supporting Member

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    Radios with electronic memory always draw current.

    My '07 Grand Marquis has a .015A draw, can set for month or more. Till computer goes to sleep(approx 25 minutes after last activity[engine shut down, unlock etc]) draws close to .25A.
     
  5. Constable

    Constable You have the right to remain silent....or not!

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    You never stated if you installed anything modern with a memory such as a stereo. If you did, that's where the draw is which is normal for the memory to be active which you already have been told. If the car is bone stock '70s, you have something called a parasitic drain. This is where most often a short or a stuck relay is creating a constant power draw. In this case, finding the culprit can be extremely time consuming and never is easy. The good news is it will be easier on an older car with much less circuitry. Best way to find the general area of draw is to hook up that meter to the battery and have someone else watch it as you'll be elsewhere under the dash. Now, pull one fuse at a time and see if the draw stops. Once you find the general area of the draw, you will have to do actual detective work to see where the problem lies and that will be the most time consuming thing you'll be doing. At least this way you've narrowed it down to one specific area of the electrical system. Imagine having to do this to a new car with a hundred different circuits. Been there, done it, sucks.
     
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  6. smegnl

    smegnl Roger Saffle Supporting Member

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    No nothing modern, except LED bulbs . I have no radio. For now i put a neg batt switch on it. Once I start the interior, ill look at the fuses.
    thanks for the input
     
  7. Constable

    Constable You have the right to remain silent....or not!

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    What I recommend for a vehicle that is driven very little is to put a float charger on while the car sits. My experience and a known fact is that batteries need to be cycled between discharge and charge to survive longer. They will sulfate if left to work only once in a long while and become a boat anchor. I've seen it with the elderly who only drive a couple times a week and short distances. I've worked on enough vehicles over the years and managed a parts store for a while and sold my share of batteries. For what batteries cost today, it makes sense to use one of these chargers and save the battery. I use floats on my Harley, Miata and the Mav as it's not a daily driver. Don't confuse a float charger with a trickle charger. Vastly different. Make sure it is a float type. Another name for them is maintenance charger.
     
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  8. smegnl

    smegnl Roger Saffle Supporting Member

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    thanks for the info. I do have a trickle charger. I did not know there was a diff between that and a float charger. I will need to investigate.

    Edit...oh wait. I guess I do have a float charger. I have this. https://www.harborfreight.com/autom...rs/automatic-battery-float-charger-64284.html
     
  9. Krazy Comet

    Krazy Comet Tom Supporting Member

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    I'd pull battery cable till source of drain is found. A small short(exactly what it is), may develop into a large one & whole shebangs turns into a smoldering lump.
     
  10. Constable

    Constable You have the right to remain silent....or not!

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    Krazy's correct that the issue needs to be fixed or it will eventually get worse but the charger will keep the battery up in the meantime and well after the problem is repaired. The Centech one you mentioned is a float charger. It will work but I'd recommend investing in a better quality one like a Schumaker or similar for the long term.
     
  11. smegnl

    smegnl Roger Saffle Supporting Member

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    thanks. I put on a neg disconnect switch until I can find time to investigate
     

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