slow battery drain?
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Junior User
Joined: Sep 2009
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slow battery drain?
so about a week ago i went out to my truck only to find the battery was dead. i jumped the truck then replaced the alternator and electronic regulator. it ran fine for the next week. i havent driven it in 2 days (usually a DD) today i went out to fire it up and the battery was dead again! any ideas on what it is? bad battery or what?
Posting Guru
Joined: Feb 2007
Posts: 1,735
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From: Wingo, Ky
Check to see if you have parasitic drain. An aftermarket cd player will have a constant drain on the battery but it should take a long long time for it to drain the battery.
I had a cd player once that would run my battery down after about two days because something was wrong with it. If you have one unhook it and see if the problem continues.
Before you do a parasitic drain test things like an aftermarket cd player need to have the memory wire disconnected.
I had a cd player once that would run my battery down after about two days because something was wrong with it. If you have one unhook it and see if the problem continues.
Before you do a parasitic drain test things like an aftermarket cd player need to have the memory wire disconnected.
Senior User
Joined: Dec 2008
Posts: 226
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Could be a bad battery. 12.7v-100% charged, 12.4-75%, 12.1-50%, 11.8-25%, 11.6-dead. To do a load test leave ignition off and pull ignition wire off the starter solenoid. Hook a voltmeter to the battery. Short out battery and starter post with a screwdriver. While engine is cranking over check the battery volts. It shouldn't drop below about 9.5 volts. For battery drain disconnect the neg battery cable and hook up a voltmeter between the neg cable and neg post. Drain on my battery is .3v. It was 11.5v until I figured out it was the electric trailer brake controller draining the battery. Pull each fuse individually and re-check volts to figure out which circuits are causing the drain. Then unplug each component to see which one is causing the problem. Time consuming but simple. It's nice to know nothing is draining your battery when you shut it off for the night.
MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
You can easily check for a parasitic draw on the battery with the truck shut off by removing the negative battery cable and attaching it to a test light, then connecting the other end of the test light to the negative battery terminal (effectively putting the test light in series with the negative battery cable). If it lights, then you have a parasitic draw. You can find the circuit that has the draw by pulling fuses one at a time. You'll want to disable the dome light, otherwise the courtesy lamp circuit will light up the test light if you've got the doors open.
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Junior User
Joined: Sep 2009
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so i jumped it took it to shucks and the guy told me i have a bad battery. but its only like a month or two old and aparantly it doesnt have a waranty! but i still need to test for a draw, i have had my stereo out for a while but the wires are all hooked up. could it still be drawing power?
Certified Thread Hijacker
Joined: Aug 2001
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I am pretty sure CSK Auto's cheapest batteries still have a 48 month warranty.
I get my batteries at either Sam's Club or Walmart. 3 year warranty no questions asked. I have, I hate to admit, taken a perfectly good battery back to Walmart at 2 years, 10 months to get another battery.
The battery in my black truck is a 5 year old Energizer MAXX.
Josh
I get my batteries at either Sam's Club or Walmart. 3 year warranty no questions asked. I have, I hate to admit, taken a perfectly good battery back to Walmart at 2 years, 10 months to get another battery.
The battery in my black truck is a 5 year old Energizer MAXX.
Josh
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