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battery draining on my car

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=122190
Printed Date: August 25, 2025 at 12:42 PM


Topic: battery draining on my car

Posted By: orandaberg
Subject: battery draining on my car
Date Posted: June 07, 2010 at 6:30 AM

Hi

My battery drain to the point I need a jump after 3 days of no use. Have change out the battery, still drains. It just suddenly happened over a couse of time, one day it just started happening, nothing new has been added that would drain it. Could a remote start drain it if the programming is incorrect? The remote was in the car for months before this happened.

Any ideas?




Replies:

Posted By: dasbogie
Date Posted: June 07, 2010 at 7:00 AM
what kind of car?  was there a bypass installed, if so which one?

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Posted By: howie ll
Date Posted: June 07, 2010 at 7:15 AM
Very unlikely, check battery, how old is the battery? Drop test voltage etc also do a drain test, all of these can be done with a DMM.
I would have thought where you lived, you'd be the world experts on battery drain. OK so maybe Canada Alaska and Russia get it worse but you know what I mean.
Sorry just re-read your post. remove one terminal, set DMM to DC current, place one lead on battery terminal, other on disconnected lead and tell us the draw, also what car.
In the oil-soaked cake making absence of Mr. I my crystal ball says Saab, Volvo, VW or Mits.




Posted By: oldspark
Date Posted: June 09, 2010 at 3:32 AM
No update orandaberg?

There are things like alternator diodes that can fail and leak...
Then there are gremlins - like the ones that inhabit my mother's 1989 car and will flatten its battery over ~3-7 days at random. (A tali-gate lamp was suspected...)

But as Howie wrote, a drain (current) test etc.
Else remove fuselinks (and later fuses) to narrow it down.




Posted By: orandaberg
Date Posted: June 09, 2010 at 7:32 PM

Hi

Thanks for thr tips,I have a 07 chrysler 300c CRD, we hooked up to test the battery it was draing 0.8 milliamps per hr, we are going to do the fuse test,battery is new





Posted By: oldspark
Date Posted: June 09, 2010 at 8:05 PM
Hmmm 0.8mA per hour.... I wonder how much that is per day....? (That's a joke...)

800uA isn't much.
It's equivalent to 1/25th of a LED, and 1/1,000th of a 10W bulb.
That seems ok (assuming that is including startermotor and alternator connections).

It may be an intermittent, or something switching in below a certain voltage... (Aren't "active"ow voltage alarms great!)

Take more readings as the voltage decreases. Assuming a (single) multimeter, take the voltage reading first, then switch to current and connect the leads to the negative battery terminal BEFORE pulling the terminal off the battery.
Maybe the current increases...

(Can also put a LED or bulb in place of the ammeter and see if/when it glows brighter....)




Posted By: i am an idiot
Date Posted: June 09, 2010 at 8:40 PM
My guess is you meant to say 8/10 amp draw.  You need to leave the car at rest for 20 minutes to let the computer go to sleep.  Do that and check the meter again.




Posted By: howie ll
Date Posted: June 10, 2010 at 3:10 AM
I'm with Mr. I here, 0.008amps is impossibly low. With all the Mercedes influenced design on that car, I would expect to see initially just under 1 amp, reducing to about 0.08 after about 20 minutes.
As a sidebar an idiot colleague pulled the glovebox and disconnected the airbag switch engaging the airbag warning light. Borrowed something off a friend and cleared it, beautiful piece of equipment, even told me the cause of the fault. When I returned it I asked how much? £4000 ($6000), oh well.





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