Date: Wed, 7 Jun 95 15:17:44 EDT
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: cetin@kirk.bellcore.com (Cetin Seren)
Subject: Elec. Leak Draining My Battery!
let me ask the stupidest question first:
How old is your battery? If it is old enough, it will have enough
internal leaks to discharge itself in 12-24 hours.
If your battery is relatively new, then read below. ( one easy way to
make sure is to drive your car around long enough to charge the
battery, then disconnect the ground strap and leave it overnight.
If the battery is still good, the next morning, then you truly
have a leak. If the battery is bad, get a new battery).
Cetin
Derek Drew writes:
> over about a 12 to 24 hour period. Short of feeling every thing in the van
>
> What I have tried is this: I have disconnected the ground strap from the
> battery and incerted an LED under the theory that the LED would be lit if
> there was a current draw in the system somewhere. (The LED is attached on
> one side to the battery and the other side to the disconnected ground wire).
> Unfortunately, the LED seems to be lit all the time, even when I disconnect
> every fuse.
O.K., we need to know the type of the led. ISince you did not
burn it, the leak is around 50mA (as in milliamps).
> Next, I tried took the little light over the driver's side and tried the
> same trick. This light was never lit at all except just a little tiny flash
> when I plugged the car stereo in.
It'll take a lot more to light a little lightbulb. What you saw
was the stereo's capacitor sucking in a lot of electrons at power-on.
The capacitor is used to "smooth" the batt. voltage and make it
"friendly" to the stereo. It does not drain power constantly (unless you
use the radio, that is...).
>
> So I am thinking that perhaps the little light demands too much current to
> flash and the LED needs too little current to light up and that I have to
> experiment with a very small incandescent bulb.
No. Since the LED did not burn out, it is the correct tool (by virtue of
being sensitive enough to indicate your problem). By any chance,
do you have a dash clock, and did you remember to
try disconnecting it? If things like the dash clock, etc.. that require
constant batt. power are disconnected, and you still get a lit LED, then
you have a leak.
> But then I am wondering--how to you trace an electrical leak by the book?
Start at the alternator / battery side of the harness, with yoru LED in place
between battery negative and the ground strap. Remove the harness. See
if you can find the different spots where the harness ends. One by one,
use a long (not necessarily thick) wire to complete the circuit between the andbatt. positive the spot that the harness delivers power to. Look at the LED.
If it's lighting up, then you got your leak. -- watch out: do NOT touch places
randomly. You will end up using your LED as a fuse, i.e., it will burn out.
Trace the harnessr(from a manual, maybe) and only try it at the end points
of the harnessur
> There must be a simpler way to trace this. I wish I had some kind of Ammeter
> and knew how to use it. Then I could see what the amp draw is and determine
> when it goes away after I disconnect various fuses.
>
Well, not really -- just hope it's reqally the battery -- your work will
be a lot easier
good luck.
Cetin
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