Battery keeps dying
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Junior Member
Joined: Jul 2016
Posts: 1
Battery keeps dying
Hi, I have a 2008 town and country. I noticed that the car doesn't go into sleep mode when turned off. Also I have noticed that the drivers side power lock keep unlocking and locking by their self. Also when the car is shut off and locked I noticed that the lock unlock within a few minutes. Please any help would me great. Thanks in advance, Mor
Senior Member
Joined: Jan 2012
Posts: 1,611
From: UK
Battery keeps dying - is it 07 Mk IV or an 08 Mk V ?
(1) Battery U/S or what have you (2) left switched on, seat power switch / vanity mirror light / messing with radio wiring / etc ? or (3) poor battery condition corrupting the BCM.
Start by fully charging the battery [seach for Leedsman] with the terminals disconnected the reconnect to re-boot the x3 computers - what happens now ?
(1) Battery U/S or what have you (2) left switched on, seat power switch / vanity mirror light / messing with radio wiring / etc ? or (3) poor battery condition corrupting the BCM.
Start by fully charging the battery [seach for Leedsman] with the terminals disconnected the reconnect to re-boot the x3 computers - what happens now ?
Senior Member
Joined: Jul 2013
Posts: 885
As Quinteq says, perform the actions.
I found in the 12volt rail on GV, there is a big capacitor (not the one I fitted). To firmly clear out micro. garbage this capacitor must be discharged. This is easy. Remove the battery negative lead from its battery post and hold it it against the positive post for a half minute or so. You may hear a "crack" as that capacitor I mentioned is discharged. This confirms the presence of aforementioned big capacitor. I don't know where this capacitor is located, but my S-type Jag. also had one somewhere on the chassis.
If all works ok. now, you will need to establish what has glitched up your microprocessors. Possible sparking at the alternator's slip-rings could be a source, but almost anything could be at the root of it, including sparking at the starter motor's brushgear and commutator assy. (This is more likely). Hence the reason for the big capacitor on the 12volt rail to "squash" any electrical 'spikes' on it, causing alterations on the strings of data bytes stored in memory. Eg., a one bit shift in a byte if it is in a stored instruction can make that instruction something completely different. In one of my postings I added extra capacitance to the 12volt rail to the tune of 100,000microfarads at 16volt working across the battery.
There is a lot of guesswork unfortunately in running down this problem. Shorts in the wiring is a possibility, and because the body control microprocessor board lives next to the battery with its acid fumes and heat from the engine, some of the plugs into that board can have that very same white excrescence on them one used to see on the battery posts in the old days. I found that white excrescence on my own processor board plugs. If yours has this, clean it off with an old toothbrush and any good contact cleaner.
Leedsman.
I found in the 12volt rail on GV, there is a big capacitor (not the one I fitted). To firmly clear out micro. garbage this capacitor must be discharged. This is easy. Remove the battery negative lead from its battery post and hold it it against the positive post for a half minute or so. You may hear a "crack" as that capacitor I mentioned is discharged. This confirms the presence of aforementioned big capacitor. I don't know where this capacitor is located, but my S-type Jag. also had one somewhere on the chassis.
If all works ok. now, you will need to establish what has glitched up your microprocessors. Possible sparking at the alternator's slip-rings could be a source, but almost anything could be at the root of it, including sparking at the starter motor's brushgear and commutator assy. (This is more likely). Hence the reason for the big capacitor on the 12volt rail to "squash" any electrical 'spikes' on it, causing alterations on the strings of data bytes stored in memory. Eg., a one bit shift in a byte if it is in a stored instruction can make that instruction something completely different. In one of my postings I added extra capacitance to the 12volt rail to the tune of 100,000microfarads at 16volt working across the battery.
There is a lot of guesswork unfortunately in running down this problem. Shorts in the wiring is a possibility, and because the body control microprocessor board lives next to the battery with its acid fumes and heat from the engine, some of the plugs into that board can have that very same white excrescence on them one used to see on the battery posts in the old days. I found that white excrescence on my own processor board plugs. If yours has this, clean it off with an old toothbrush and any good contact cleaner.
Leedsman.
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