# Electrical problems - battery drain



## mip1 again (Apr 9, 2006)

Hi all - not posted on here for ages.

I have a problem, my phaeton (details below) appears to be completely out of electrical power after being left for a couple of hours or more. No lights, no central unlocking and starting only works when key turned 'the other way'. When it does start a wide range of error messages appear, but disapear once running, the clock sets itself to 12.00, mileage information on the central console is reset to zero etc etc. 

After a journey everything seems fine again, keyless locking works fine and all seems normal.

I suspected a dying battery and have had it in my local dealers today for diagnosis - they advised that it wouldn't be the battery itself but something else causing a constant drain on it. They contacted VW UK to see if they knew of any likely faults, but drew a blank.

They got a reading indicating that the lock on the passenger front door was signalling that it was being activated constantly so disconnected it, but the drain was still there. They then disconnected all control units in the boot area, but drain was still present. They advised that the next step was to get the dashboard out and check everything there but I wanted the car back and also have a bit of a fear that they'll take ages (and cost a fortune!) so I'm having a think before letting them loose again.

I've had a quick read through various threads and nothing obvious has jumped out at me; I'll have a deeper search when I have time. In the meantime, does anyone have any ideas what the problem might be off the top of their heads? 

I'm assuming that it's the right hand (starter) battery that's draining - does that sound correct?

The car is the V10 diesel, 2004 model and has keyless locking and starting. I love the car and have known that keeping it will entail occasional financial 'shocks' - I just can't see anything I want to replace it with 

I can't tell you how grateful I'd be for any ideas that anyone might have.

Thanks
Jim


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## Zaphh (Jul 5, 2008)

If you are in real despair, you can start by something like charging the battery, removing some fuses, and find out if this makes a difference.

As a computer scientist, dichotomy tells us that finding which fuse causes the problem among 256 fuses would take 16 manipulations (= 16 days ?) or much less, if you can put an Ampmeter (be careful, use a big one) in series with the battery, to find out how much current is drawn.

I think you could also put a big (read high amperage) resistor between the battery and the car of a know value, and put the ampmeter in parallel. If you know the value of the resistor, and the value of the internal value of the ampmeter, you would know what percentage should go through the ampmeter, and which percentage should go through the big resistor (the total of both being the total current that is drawn).

But I'm only thinking theory. It is probable that there are other ways / meters to measure a drawn current (garages probably have ampmeters that can take hundreds of amps).

Note that if the current leak is not too large, then, a standard £10 ampmeter may be able to take it without frying...

If you have a basic ampmeter at home, you can still measure the permanent current that is drawn and not the transitory current if you follow the steps below:

1° disconnect the left battery, take a reasonable piece of conductor with two clips on the end (a charging cable would be perfect) and connect the battery to the car connector through the charging cable, so that current towards the car flows through the charging cable.

This will take care of the surge of current that always happens when you first connect a battery to a car whose many electric devices have been wanting electricity for a while.

2) Once everything is connected (all the modules drew the current they wanted until they set back in permanent regime), the ampmeter may take the trickle discharge that provokes your battery drain.

So, connect your ampmeter in parallel with the charging cable, one clip on the battery, the other to the car battery connector. The Ampmeter should read 0, as all the flowing current will go through the charging cable (the ampmeter has an internal resistance).

3) Then, disconnect the charging cable. The only path for current between the battery and the car will now go through the ampmeter. Because the transitional regime is over (that could draw many amps), your ampmeter won't get fried, as it will now only measure the permanent current that is drawn by the car (which should be reasonably small). I think that a value above 100mA should indicate a problem (so the ampmeter may show a greater value than 100mA.).

Now, you can do a really stupid but efficient thing: get to a fuse box, and remove ALL the fuses one by one, and check out what effect is obtained by removing a fuse. If your ampmeter showed a current of 500mA and if this value drops to 50 mA when removing a particular fuse, you know who is the culprit. Beware, by putting the fuse back, you may create a large temporary surge of current from the battery to the defective apparatus that may fry the ampmeter...

Maybe you could try this out before sending the car back to the dealer ?

P.


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## WillemBal (Nov 20, 2010)

Hi Jim,
Battery drain problems can be real headaches, even for dealer technicians. There are so many components which can be faulty, that it is impossible to sum up some possible causes.
In theory, defective diodes inside the generator can cause problems, or the big capacitor in the electronics box under the plenum chamber. These are the main components which are virtually always connected to the battery, also when the car is locked.

You might want to ask your dealer whether they can check if there is indeed a permanent drain on the battery when the car is locked. Please ask your dealer whether he has a current clamp. More specifically, a F*LUI80I-110S*. This is essentially the VW/Audi equivalent of a *Fluke 80i-110S* AC/DC current clamp 50 mA…100 A, which can be simply clamped around a wire through which the current must be measured and connected to any DMM for the readout. Fully inline, non-invasively. Still, the diagnosis work is a bit tedious, since the trunk lid must be closed in order to make valid measurements.

When it has been determined that there is a battery drain (consumption is normally 30 to 50 mA when the car is locked), then the diagnosis can be continued by disconnecting specific suspect components, or by pulling fuses to exclude specific circuits of the car, similar to what Pierre was suggesting. Measuring the current then helps to isolate the problem.

It is also worth to lock the car, then listen whether there are audible noises of pumps, valves, fans and other electromechanical components. If this is the case, then it should be easier to isolate the problem to a single component.



mip1 again said:


> - they advised that it wouldn't be the battery itself but something else causing a constant drain on it.


It may be worth to check the cooling water level. After driving, some water pumps or valves are still functional, but with a low level of cooling water, they may continue to function forever. I remember one owner who had a problem with a *draining battery* AND with *noise* coming from under the bonnet. After it was suggested that the cooling water might be too low, no more posts were made by this owner.  This might suggest, that the problem was solved by just a simple action. So please have this checked first, before the diagnosis becomes a nightmare.

Willem


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## PanEuropean (Nov 3, 2001)

Hi Jim:

Excellent suggestions above from both Pierre and Willem.

Based on the symptoms that you describe, the battery that is draining is the left battery (the vehicle power supply battery), not the right battery (the starter battery). The starter battery is used exclusively for cranking the starter motor. The fact that your car starts when you invoke the 'emergency start' routine (turning the key fully clockwise, then fully counter-clockwise, then fully clockwise again) proves that the starter battery has power. The fact that the lights don't work, the various volatile memories (like the clock) get flushed, etc. proves that the vehicle power supply battery (left battery) is in a very low charge state.

I am very apprehensive about the suggestion made to remove the instrument panel - I don't like the sound of that at all. Removing the instrument panel is "major surgery", it is a very complex undertaking and brings with it all sorts of risks that things might not get put back together properly, you might have squeaks and rattles, everything might not line up correctly, etc. So, I think you were correct to dodge that bullet.

Pierre's suggestions are very logical, but the problem is that the Phaeton tends to "think around corners". In other words, in order to get access to a fuse panel (there are three of them), you need to have either the bonnet, the boot lid, or the driver door open. Once you open one of these, the car will 'wake up' and begin consuming energy in anticipation of being used by the driver. So, you might have quite a number of 'distractions' taking place that could be misleading.

I think that in a situation such as yours, the first thing that the technician needs to do is sit down at the Volkswagen computer terminal in the office of the service department and start researching technical bulletins (sometimes called 'Technical Solutions') to see if there is any guidance published by VW for this exact problem. Next action would be to contact the technician's help line and get some expert advice, either from the service support people at the UK importer level, or perhaps even from the service support people in Wulfsburg or Dresden.

It should be possible for the technician to diagnose where the electrical consumption is happening by cracking the driver door window about an inch, plugging in the diagnostic scan tool, then looking at MVBs (measured value blocks) for the various controllers. To do this properly, reference to maintenance publications is essential. For example, the interior anti-theft monitoring will need to be turned off during this process.

I have always been very reluctant to criticize the maintenance technicians here in the forum, however, in this particular case, I think you need to have a talk with the service department manager about the need to get assistance from 'higher up' in diagnosing the problem. It sounds to me a bit like the maintenance technician is 'shotgunning' the problem - in other words, making interventions without a sound plan in place, in the hope of getting lucky and finding the cause of the problem.

Michael


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## PanEuropean (Nov 3, 2001)

Jim:

Just a couple of last-minute, super-simple things to check:

*1)* Do you have the parking heater option (little device that will warm the car up when you set a timer or press a button on a remote control)? If so, make sure it is not programmed to come on at the same time each day.

*2)* Does the car make any sounds (noises) when it is turned off? It's normal to have a few sounds from the front end of the car for a few minutes after it is turned off, but you should not hear any sounds beyond about 5 minutes of shutdown.

*3)* If you have keyless access, the technician should check the four door handles to make sure that there is not a spurious lock or unlock signal coming from one of them. By itself, this should not result in battery drain (the car should ignore the problem door handle after a series of unsuccessful requests), but it is worth checking, and can be done very easily with a diagnostic scan tool.

*4)* Check the age of the left battery (vehicle power supply battery). If it is older than 5 years, replace the thing. You will have to replace it sooner than later, so you might as well replace it now. It is entirely possible that the battery itself is toast, that your initial hypothesis was correct. If it is the original battery (you can tell from the stamp on the top of the battery post), then the odds are that it is the cause of the problem. Be sure to buy a OEM spec VW battery - I know they are expensive, but the battery is the one part you never, ever want to skimp on when you replace it.

*5)* This is a shot in the dark, but: Next time you park the car at home, make sure that all of the keys for the car are out of radio transmission range of the car (for example, put them in a zip-lock bag in your fridge or some other location where it is simply impossible for a radio emission from the key to be detected by the car). Then see if the battery goes dead. If one of your key fobs has deteriorated to the point where it is constantly transmitting a 'lock' or 'unlock' signal, that would prevent the car from going to sleep - which it normally does about 1 minute 55 seconds after it gets locked up - and that could be the cause of the battery drain.

Michael


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## dlouie (Oct 31, 2008)

Michael, 
It's a very good point that you bring up about waking the car and potentially obtaining inaccurate current drain readings. There must be a way to fool the car into thinking all the doors are shut and it's time to go to bed. My approach would be to keep the car asleep and then taking current readings at each fused circuit by removing the fuse and bridging the terminals with the ammeter. This should be relatively safe for testing puposes because if there was a short or excessively high current drain, the fuse should have been blown which is not the case. Take note of all readings for every circuit and determine which circuit may be the offender. Keep in mind that it could be a combination of circuits that can contribute to the overall excessive drain when parked. Also note that aftermarket systems can cause issues also. Is it possible that something is keeping the car from going to sleep? Just my 2¢. 

Damon


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## jkuisma (Nov 23, 2009)

Hi! I dont have much to add to the excellent suggestions already provided, just some random pieces of information from my own experience. My car had a stubborn drain problem last winter and while troubleshooting it, I learned a few things:



> Based on the symptoms that you describe, the battery that is draining is the left battery


Yep, this is for sure! Replacing the battery, as Michael suggested, is recommended in any case. Don't do it unless you have diagnosed the drain issue first, though, as deep discharging will quickly destroy the new battery.



> if you can put an Ampmeter (be careful, use a big one) in series with the battery, to find out how much current is drawn.


This is my experience on how to measure battery drain with a regular ampmeter.

The measuring "clamp" suggested by Willem would suit best for this job, but a "standby" leak can be measured with a regular ampmeter, too. You need an ampmeter which is good for at least 10 Amps (mine has a separate port for 10A unfused). 

Park the car. Open the trunk. Close the doors. Lock the car. Let it sit for a few minutes. Car will go into a "sleep mode" as explained by Michael. Have two about 2 meter long wires (with at least 2,5 sqmm diameter) handy. Loosen the accessory battery (on the left) positive terminal. Wrap one of your (stripped...) loose wires around the base of the positive battery pole (with the actual positive terminal still connected to the battery). Now, strip and fix the other wire to the positive terminal which you will soon disconnect from the battery. Now, attach the other ends of the loose wires to your ampmeter. You should now have a "trip wire" running from the battery pole to the ampmeter and back to the positive terminal on car's wiring. You can now (carefully) disconnect the positive terminal from battery pole. Don't do this if there are any electrical consumers on (car should be locked, in "sleep").

Take the ampmeter out of the trunk and close the trunk lid. The two wires will not be crimped - there's enough space between the trunk lid and the car's body for them to stay intact. Wait for a while for the car to fall in sleep again. Now observe the ampmeter readings. As the car is now supposed to be in "sleep" you should see only about 30-50 milliamps (exactly as was mentioned by Willem) of current. If you unlock the car, the current should jump to around 8 amps. I never saw it going over 10 amps (therefore potentially breaking the ampmeter). Just don't attempt to start the car with the trip wire in place! 

Now, with the ampmeter connected to the circuit, you can unlock the car, pull out any fuses you suspect, lock the car again, wait for it to go to sleep and look at the ampmeter readings. With some luck you will find the right fuse / controller causing the drain. In my case there wasn't a single fuse I could track the fault to. In my case the CAN BUS never got to sleep and maintained a constant ca. 3 amp drain from the battery. This was caused by a faulty "TV-Free" box (a cheat box which goes between the ZAB/navi and the CAN BUS, enabling viewing of TV picture while on the move). Removing the box was the fix. It was later reflashed by the manufacturer and everythings working fine now.



> the car will 'wake up' and begin consuming energy in anticipation of being used by the driver


As I mentioned above, this was the problem with my car. What I observed, though, is that the intelligent battery saving features in a Phaeton prevent the battery from going TOTALLY empty. My car always had enough "juice" to, for example, respond to remote and at least blink the blinkers. Clock and other memory presets were always preserved! What Jim explains (a 100% total battery drain) sounds really special and makes me think that the drain is somewhere, where there are no "intelligent" electronics in place to prevent it. Therefore it sounds to me more like an alternator diode or other similar "electromechanical" fault than something wrong with the CAN BUS controllers.

Hmmmph, but still: Jim mentioned that the VW technicians mentioned something about "oddly behaving" door lock. I would definitely rule out water in the KESSY at first. A "simple" battery drain would be a logical but very mild symptom of the potentially catastrophic water ingress fault!

I can't understand why anyone would suggest "taking the dash apart" as there are not that many controllers inside the dash itself - they are scattered around the car. Trying to find the fault just by taking out the controllers one by one would be like searching for a needle in a haystack.

Jouko


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## dlouie (Oct 31, 2008)

Try this procedure :
http://forums.vwvortex.com/showthre...ain-Help-!&p=73048591&viewfull=1#post73048591

Damon


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## mip1 again (Apr 9, 2006)

Thanks so much for all the suggestions. Instantly, the level of intelligence surrounding the problem has increased. I don't like to crticize the professionals either, but a problem I have with my local dealer is that you never get to talk to the techniicians, there's always someone 'front of house'.

I'm not very technically minded but I'll have a good think about everything you have suggested, I'll try to talk to the right people at the dealership and I'll keep you all posted.

Thanks again!
Jim


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## ilhan34 (Jan 5, 2012)

*battery drain*

hi
my nam is yan i live in france 
i have phaeton v10 tdi and i have a same problem 
everythink is ok but when i park my car for 1 days the next day i don t have car acces and don t have keylesgo 
i start whith the key in inginton

do you have a solution


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## PanEuropean (Nov 3, 2001)

jkuisma said:


> ...Jim mentioned that the VW technicians mentioned something about "oddly behaving" door lock. *I would definitely rule out water in the KESSY at first.* A "simple" battery drain would be a logical but very mild symptom of the potentially catastrophic water ingress fault!


Jouko makes an excellent point.

See these discussions, there is a multi-page tale of woe in one of them about water damage to the *K*eyless *E*ntry and *S*tart *Sy*stem (KESSY):

Water in Cabin Footwell (Cleaning Air Intake Plenum and Sunroof Drains)
....Water in Cabin Footwell (Leakage via Electronics Box in Right Plenum Chamber)
....Water in Cabin Footwell (Leakage via Air Conditioning Evaporator Pan or Evaporator Pan Drain Lines)

The source of the water is most commonly from the bottom of the car, via a damaged or missing plug in the body of the car. In some cases, the water can come in from one of the three sources above, but that is not as probable as water entry from an opening in the bottom of the car.

See also this thread:

Damage arising from Towing & Flatbed Transportation

Michael


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## PanEuropean (Nov 3, 2001)

See also this discussion about water damage / infiltration to the KESSY controller: Car won't unlock, recognize key, release key from ignition, or start (wet controllers?) 

I'm not suggesting that this is a 'probable' cause of your difficulties, and it would be very wrong to jump to conclusions at this stage of the game, but as Jouko mentioned above, you should certainly rule out any possibility of water infiltration affecting the KESSY controller before you go any further. Heck, just from a preventative maintenance point of view, you should make certain that there is no underbody damage, all the rubber plugs down there are in place and properly sealed, and that you are not getting any water coming into the cabin via the sunroof drains, via the electrical box in the plenum, or via the evaporator drain lines. Be aware that the electrical box in the plenum _might _be in a different location in a RHD car. The sunroof drains and evaporator drains will be identical on RHD and LHD cars.

I'm not exactly certain where the KESSY controller (the J518 Access and Start Control Module, which is controller 05) is located on RHD cars. On LHD cars, it is under the driver footwell (left front footwell). I am going to guess that it is in the same place (left front footwell) on a RHD car, but you will need to confirm that.

Michael


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## WillemBal (Nov 20, 2010)

mip1 again said:


> I'm not very technically minded but I'll have a good think about everything you have suggested, I'll try to talk to the right people at the dealership and I'll keep you all posted.
> Thanks again!
> Jim


Hi Jim,

As you said that you are not so technically minded, the excellent recommendations above may perhaps cause you more troubles than you already have.  I'm tempted to say that they are even difficult to understand/execute for most dealers, since most of the technicians only have some basic electrical knowledge.
Most important is that when you search help from a dealer, please make sure that it is a Phaeton dealer and not a *normal* VW dealer. I trust my car to normal VW dealers only for simple mechanical work, not when it comes to electrical work and diagnosis. Trust me when I tell you that normal dealers do not even know where to connect the battery maintainer during diagnostic work. They think it is a kind of Touareg and connect it to the poles under the bonnet, or to the battery on the right, both being wrong.

It is indeed true that you normally talk to the service managers or one of his co-workers who are planning the work. But you might be able to talk to the specially trained technician, when you kindly ask... and be a little persistent. Just tell the service manager that you need to discuss some specific technical issues and that you feel more comfortable when you have talked to the technician who is going to do the work. A good dealer won't deny you this privilege.

Willem


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## gartracescort (Apr 4, 2010)

My '04 V10 did this before Christmas (posted elsewhere) and followed the volume control going loco. All of it was a one off and hasn't repeated thank goodness.

My assumption is a one off software glitch. Neither fuse for the infotainment/stereo cured the problem, in fact the drain occurred when the stereo fuse was out. The volume has been fine ever since the electrics partially reset due to the drain that took the battery down to approximately 4.3V. Thank goodness the boot opens manually when needed.

Weird, but true. Intermittent problems are a pig. The error codes were ballistic after the power drain, there were lots & lots to pick from, and the error hasn't recurred to trigger any individual one.

I await it recurring with keen anticipation!!


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## dlouie (Oct 31, 2008)

I once had the hazzards flash by itself while going at speed and then display stated that the srs had an issue. It cleared itself in few seconds.

Damon


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## Ekremsky (Sep 8, 2010)

*battery drain*

Well,I have the same problem,I went to many VW Technicians,but no one of them could make a diagnosis...
So I tried so many thingsbuying a new battery,replacing the generator,replacing the capacitor under the plenum chamber,removed the fuse for the solar sell sunroof,removed the fuse for the rear memory& rear heating,there was a annoying sound from the claps in the clima,so I put a switch to the fuse of the climatronic controller,no one of these things helped me,I still have battery drain,sometimes there is no drain for 3-4 days,but sometimes in 1-2 hours the left battery is dead under 10 volts...
The measurment with ampmeter shows between 50ma and periodicaly 3-4 A after locking...
The only thing I did not try is the TV-free adapter....may be...don't know,you must try,I don't beleive too much to the technicians,as they suggest only the easiest way,replace this rplace that...I will watch this thread closely.

Regards,Ekremsky


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## mip1 again (Apr 9, 2006)

*Battery update*

Hi Guys 

Been meaning to post an update on this little saga... 

I ran the car just on the RH battery for a few weeks while cogitating about what to do - the car seemed fine although died every time I left it. 

Eventually decided to get the LH battery replaced before allowing my dealer to keep trying to diagnose the problem. This was replcaed about a month ago and has *completely* cured the electrical problems. The car feels like new again and I love it again. 

Managed to have a brief conversation with the Phaeton tech and made the mistake of mentioning the forum - not in anyway to take away from the fact that he was the professional - and the only thing he would say was 'we have a lot of trouble with forums'. Yeah, thanks for getting me to spend £200 while you try to diagnose an electrical fault that could be fixed by what the forum told me! :sly: 

Anyway, just wanted to update you all. 

Cheers 
Jim


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## Expoman (May 15, 2011)

ilhan34 said:


> hi
> my nam is yan i live in france
> i have phaeton v10 tdi and i have a same problem
> everythink is ok but when i park my car for 1 days the next day i don t have car acces and don t have keylesgo
> ...


 Hi, 

I also live in France and have a V10 TDI. 

I had the same problem as well which was solved by a new Left Hand Side battery but also have the technician check the Kessy (they call it it Kessy in French as well!). 

Best, 
Steven


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## Expoman (May 15, 2011)

mip1 again said:


> Hi Guys
> 
> 
> Managed to have a brief conversation with the Phaeton tech and made the mistake of mentioning the forum - not in anyway to take away from the fact that he was the professional - and the only thing he would say was 'we have a lot of trouble with forums'. Yeah, thanks for getting me to spend £200 while you try to diagnose an electrical fault that could be fixed by what the forum told me! :sly:


 Jim, 

It seems all about individual attitude. My VW tech here in France is just sorry that his limited English makes it impossible for him to read what goes on here, he is always very interested in any feedback from the forum on any issues, none of the arm around the shoulder "just leave it to the professionals sonny" at all. 

All best, 
Steven


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## gartracescort (Apr 4, 2010)

My problem still hasn't recurred, even through the coldest weather. It has to go back AGAIN for door repainting, so I'll point out the missing floor plugs when I get it back......they were missing after last time, but it was a few months later that I noticed so I'll "notice" it straight away this time.


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## seawind3000 (Sep 17, 2010)

I just finished a visit to a VW shop in Kitchener Ont. They were all ears to the advice this forum had to offer, I was very pleased. They took 1 hour to change the serp belt, so they just leaned the rads ahead, not remove the front of the car like the shop manual says.

Almost all my warning lights are off now, just the TPMS left and that should be corrected in a week.

Mike


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## PanEuropean (Nov 3, 2001)

*Archival Note:*

See also this discussion, especially posts #12 and onwards, for additional discussion of battery drain concerns - ....Smoothing Capacitor - A possible cause of persistent, unexplained battery discharge 

Here are some additional discussions (all of which are listed in the Phaeton Forum 'Table of Contents' (FAQ by Category)) about various battery problems including battery drain:

Battery - Vehicle Power Supply Battery (not starter battery) Problems
....Additional discussion of problems arising from discharged batteries (battery management controller replacement)
....Electrical Problems (includes TB 27-06-02, RVU, Campaign OH)
....Battery Discharge Discussion (including pictures of solar recharger)
....Smoothing Capacitor - A possible cause of persistent, unexplained battery discharge 
....A possible answer for the battery discharge problem
....Battery Replacement Procedure
....Intervention Load Management on the Phaeton (contains VW Technical Bulletin 27-05-04)
....Purchasing and using a Battery Maintainer for your Phaeton (Includes TB 00-03-11)
....My Phaeton's electrical problems are now long gone...

Michael


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