[V8] Battery draining possibilities?
v8q at bellsouth.net
Fri Mar 3 13:52:53 EST 2006
Fyi, a 150amp shunt can be bought for 20 to 25 bucks. Then its easy to
test current drain issues.
dsaad at icehouse.net wrote:
>How are they measuring the current load? You will need a good meter to measure
>accurately in the milli and micro amp range. I am not really sure what a
>"normal" load would be, but I would guess less than 100 microamps.
>1/10 of an amp is 100 milliamps. This is a significant load and will drain a
>battery over time. This works out to about .012 watts, or about one standard
>incandescent instrument panel light bulb. Not enough to drain a full battery in
>a day, but a few weeks maybe. A small leak like this tends to keep the battery
>discharged enough that the alternator has to always work hard to pump it back
>up, causing both the alternator and battery to work hard and wear out.
>I wonder if you are using the correct battery? Your usage seems to be quite
>high. These cars take a pretty high capacity battery so if you are using too
>small a battery, the normal alternator charging current may be killing them.
>The usual method to locate the current leak is to disconnect the door switches
>and set the car into its shut down mode - meaning the retained power system is
>off, interior lights off, etc. Then measure the current draw and start removing
>fuses until you find the leak.
>Quoting Karl Middlebrooks <coalblacksmith at gmail.com>:
>>V8 #1, which started eating batteries (went through 3 or 4 in the course of a
>>month) in December finally got towed to the shop yesterday with what I
>>thought would be problem(s) with the alternator, voltage regulator, or
>>The folks at the shop got the car up and running after blowing carbon gunk
>>out of the valves to get compression on the cylinders again (proof that the
>>V8 hates just sitting around with nothing to do for a couple of months),
>>recharged the battery and found no problems with the alternator, the voltage
>>regulator, or the charging system. Amperage was great, and with the car off,
>>it's pulling less than 1/10th of an amp, according to the mechanic. They
>>weren't able to find a short or anything else that might explain the original
>>Anyone have any ideas what might be going on here? When the car started
>>eating batteries, it would work fine one day and then less than 24 hours
>>later, the battery would be dead enough that sometimes the central locking
>>system wouldn't even work. A jump start would get it running again, and then
>>one day, it wouldn't jump any more. I'm absolutely vigilant about turning off
>>lights, stereo, and other doodads that could draw power when I get out of the
>>car (e.g. car phone charger).
>>I'd like to have the car in good working condition. It's been pretty well
>>taken care of, and I hoped to get it up to at least 300,000 miles before
>>thinking about doing something drastic with it, but if I can't figure out why
>>it might have been acting up, I'd have to look at parting it out.
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