In my own car, I sometimes see it hovering from 13.5 down to 12V with engine running idle. I haven't got the faintest idea what happens then. Increasing the engine RPM brings it back to 13.5 V.
Try Address 71: Battery Charger 3D0 915 181 C.Where would you pick up and log system volts with VAG-Com??
From the advance measuring blocks (I think), it is Group 1 - Field 2 , Terminal 30 (Comfort battery). There should be a “Current - Term 30 (Battery)” as well. It would be interesting to see what that current is reading. Mine is always zero.
Interesting. I was pretty sure that the dash volt meter would be a class II device, i.e. 2% of range (+/- 0.3 V). I think it is an analogue instrument, connected to a DAC. This DAC would convert the battery voltage as given by the CAN bus back to an analogue signal.I've certainly been measuring 11.5V at the battery with a branded digital multimeter,whilst the dash voltmeter is showing 12.5V.
An infamous problem of needle type of indicators is the viewing angle. The difference between the viewing angle as is the case when we look at the meter, versus the optimal angle (slightly at the right of the steering wheel) is almost +0.5 Volts!
I think you mean to say that your multimeter shows the same trend? I.e. reads 11.5V versus 12.5, and 13.5 versus 14.5 on the dash meter? That makes sense. When it is really showing 14.5 on you multimeter, then it would be way too high. To be honest, even the often reported 14 and 14.2 Volts seem to me rather optimistic. The only time that 14.2 Volts is ever reached, would be with an external charger such as the one you have. Smart chargers “measure” the status of the battery prior to charging it. Then they do a bulk charge, then top off the charge up to 14.2 Volts. But in a car battery management system, it cannot work that way, because the many consumers blur prevent an accurate measurement of the charge status of the battery. The float charge principle always limits the charge current to a safe level in order not to damage the battery. So it is only logical that the voltage of a discharged battery cannot be 14.2 V shortly after you have started the engine.. I have not yet ruled out the multimeter.. but as it's showing readings I believe for the conditions.. and it seems to follow the battery volts up to 14.5V when appropriate, I think it's OK.
This gives food to the thought that the dash meters aren’t that accurate as I assumed. My own dash meter usually is hovering around 13.5 and only reaches 14 on long trips.
That’s the spirit!I'll keep researching it!
It would be a small effort to calibrate (determine the deviation) of the dash voltmeters on a next GTG.
Got to go to work now... bit depressing... would rather carry on here....
Mine was just slightly over 14 when viewed slightly from the right - I even gave it a little tap on the glass face like in the old films!
When I switched on the lights and engaged the full beam, it dropped to 14 dead.
This has been a very interesting topic (I know Stu, you're right, I must get out more!) it's very good to be able to manage a problem like this by understanding what is going on.
Given the type of constant consumption the Phaeton has even when standing locked, the lack of use to which my car has been put over the past month, the unusually low temperatures and the considerable time of driving (4 hours) needed to replenish it, I think I have as good as evens a chance that the battery may not need replacing.
By this time this coming Saturday all will be revealed - how exciting!
Ok, so after charging the battery, it seems that the Phaeton is satisfied The currents are about 13.8V on the battery, aswell as on the analogue dash readout.
The problem with the trunk remains though It doesnt respond to either command - press on VW emblem, remote open, or the one in the drivers door. Only the turn signals flash. When I open it with the key, and want to close it - no response to the close button.
I found a thread, where people say, that the trunk can behave strangely when something is not right. I tried all possible combinations, still no luck.
Any suggestions? Expoman does your trunk work now?
Does everything else work the way it should? If so, it looks like this is not a battery related problem. Perhaps it is just a matter of synchronizing, or something mechanical in the lock itself. Please take a look at this THREAD.
Boot lid - yes, it works but it still has it's moments - often I have to restart the car and use the button on the door arm rest to close it because it won't respond to the remote control or pressing the emblem (although a suspicion is that here again the lack of battery power might have been causing this).
You will find copious amounts of discussion on the boot lid on this forum- good luck!
So, the saga continues!
I drove the car for 6 continuous hours and got a reading of 13 after switching off then switching just the ignition on which fell to 12.75 when I flashed the full beam.
All functionality had returned however the following morning I had to open the car with the key again, the battery had drained.
A journey of 400km followed by which time the battery was up to 13 again then the following morning the car was taken in by Listers of Coventry for the major service.
They reported to me that they had done an extensive test and the LHS battery had passed with flying colours and the only fault that came up on the scan was an intermittent fault with the power boot (trunk) which probably also explain the one-off closing phenomenon mentioned in the exchange of posts with Pierre.
So, next step is to book the car in here in France for exploratory work on why the battery is draining overnight even in warm temperatures.
Any ideas gentlemen?
Either your car continuous to consume battery power after shut-down, or the battery drains by an internal defect, which I feel is unlikely in the case of AGM batteries.
After driving, the car seems to be doing a couple of things, i.e. continues to cool the engine or transmission. This cooling process may not work properly (and continue forever) when the necessary components are defective (i.e. solenoid valve) or when the coolant level is simply too low.
I would suggest to listen carefully whether some unusual noise can be heard, approximately 15 minutes after shutting down the engine and locking the car. A stethoscope would be ideal for this diagnosis. And of course, please check the coolant level to rule out that possible cause.
I hope that your dealer in France has a clamp-on current meter to measure the drain current on the LH battery when the car is locked. Even then, it is quite difficult to locate the cause of the drain.
To definitely rule out the battery as cause, I suggest to disconnect the LH battery overnight and check the charge status the next morning. The chance may be quite small that the battery drains while disconnected, since the battery test was OK. But on the other hand, finding a fault in the car's electrical system is very time consuming and disconnecting a battery overnight is zero effort.
What you write makes perfect sense but what the hell did I do with that bloody stethoscope?
Can I disconnect the LHS battery without some complicated procedure being followed?
I have very considerable confidence in Pierre, the Phaeton tech at my dealer here in France as well as the fact that the labour here is half the cost per hour than it is in the UK.
IMO there is definitely something coming into play when the car is switched off then left locked overnight - run it for an hour, lock it on the key fob, return and unlock it, even start it keyless, no problem. Leave it overnight, entry by key is the only option.
Pierre is on his hold next week so my baby goes in on the 12th - I'll keep you informed.
Many thanks as ever for your helpful advise,
It would appear that part of the problem of diagnosing the recent difficulties with my battery has been brain fade of the owner of the car. He can offer some excuses - the period leading up to large events is very intense and it's hard to think of much else but................................
It struck me today that I recently installed the Solisto MP3 unit in place of my CD Autochanger so I unplugged it last night when I locked the car - result : car opened normally this morning, LH battery not discharged, so QED you might say.
But then I thought again - there was no problem with this in the period immediately after the Solisto was installed, even I was sufficiently attuned to the new piece of kit being installed that I was monitoring to see if anything odd was happening. And then it struck me - the ProClip.
One of the features is that instead of plugging the cable into the iPhone every time you get into the car, you plug the cable into the bottom of the Proclip which has a connector that fits into the iPhone itself allowing very easy insertion and removal as well as charging the phone and it is this I am convinced is causing my battery to drain overnight - if it can charge, not can drain is the I see it but I'm sure Willem will have something to say on this.
So, I am giving the car another night not connected to the Solisto and if it is fine tomorrow, as I expect it to be, I will reconnect the Solisto but without the lead being connected to the ProClip and see how that goes.
I have however noticed a clunk from the near side rear of the car (RHD) every time I switch off and on and I think this is the intermittent fault with the boot (trunk) picked up on the UK dealers scan (of course it may be nothing to do with it but I feel like I am on a roll!).
We'll see, she's booked in with the excellent Phaeton technician in my local French dealer next Monday whereupon I hope all will be revealed.
As ever, I will keep you posted.
Yep, just make sure you disconnect the negative lead only. After reconnecting, you will get some errors, i.e. a suspension error. This will disappear after driving it and learning it the high and low levels.Can I disconnect the LHS battery without some complicated procedure being followed?
When a fully charged battery drains overnight, then you must be thinking about some device that pulls a couple of amps, perhaps 5 amps, continuously. A leak that causes either heat, or noise, or both. All together, I must conclude that it might have been better if I had suggested to use an infra-red camera..
Anyway, the car is now in the hands of the professionals and I must say that I have confidence in the French Phaeton tech at my local dealer more, I am afraid to say, than my fellow countrymen back in the UK.
I will post their conclusions............
The latest twist in the tale is that VW Saintes have called and the LHS Battery is dead and needs replacement!
Their guess is that in the UK at Listers of Coventry they tested the RHS battery which is fine.................
There was a fault with the boot (trunk) lock mechanism which is being repaired as we speak.
I am collecting the car this afternoon so more later.
I need some new tyres on the front so I have taken Pierres advice and ordered them with the dealer - it's a little more expensive but it'll be worth it to avoid the risk of being called a tight rosbif!!
Next time you think of bringing your car to Blacklisters, you'd better say your prayer ...Their guess is that in the UK at Listers of Coventry they tested the RHS battery which is fine.................
But seriously, isn't the dealership we put our trust in, the most complexing factor in owning a Phaeton?
I asked for some floorpan bungs in advance of a booked service, but unfortunately the wrong ones were ordered and had to be re-ordered. So they weren't fitted, but arrived the day after. They were supposed to be posted to me, but never arrived. So I just drove 140 miles to the dealer (not solely for that!) and paid £4 for a second lot.
We will see what happens.
But their coffee is OK and the workshop is very nice.
At least the new floor display car was a lovely black/sonnenbeige SWB TDI with sunroof, so I had to sit in it to feel the difference. But it just felt exactly like mine, so not much incentive...
I entirely agree.
From what I have seen in the UK (2 dealers), the VW standard is simply not that which can support a car of the complexity and value of the Phaeton. Alan Day in London was simply appalling, Listers in Coventry appeared better at face value (although I did not visit their premises) but clearly were well short of the mark in terms of care and attention to doing the work itself although they did collect and deliver the car back on the same day and I formed the impression that they were honest and the Service manager was pleasant, courteous and professional as was the guy who collected and delivered the car.
I only have experience of 1 dealer in France but it's another world - the Phaeton Tech obviously knows the car intimately and clearly enjoys what he does and the service manager is excellent. It's the little touches - when you arrive at the appointed time,(these are split by the half hour so there is no hanging around while they deal with the previous person) there is a stand in the service reception saying "Welcome Mr.(Your name)".
Sure, doesn't do a thing to the car but it speaks of an attention to detail which suggests that will be carried through in all things that they do and that, in my experience with them, is the case.
They removed my CD player and fitted the Solisto for me free of charge when I popped it in without an appointment a couple of months ago and that for me is real customer service.
How's the car running? Did the replacement battery cure your problem? I hope it's done the trick for you.
I also have a 54 V10 which 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 even 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 for diagnosis - they advised that it wouldn't be the battery itself but something else causing a constant drain on it. (I'm pretty sure the battery will be the original as the car was less than a year old when I bought it.) They got a reading saying that passenger door lock was causing a drain, disconnected it but the drain persisted. They disconnected all the control units in boot area - still draining. Their next step was going to be removing the dashboard but i stopped them there - i'm not technical by any means but that sounded too scary and they obviously don't really know where to look.
Unfortunately I don't have a lot of confidence in my dealer (I may be being too cynical here!) and have been running the car without getting the problem fixed. I feel a bit stuck to be honest. Got a power fade yesterday which I know will be the turbos, and that this could be because of the electricals so I really feel like I need to do something now.
Am wondering whether I should at least just try replacing the battery to see what happens.
Jim 2004 V10
Hi mip1 (sorry, don't have your name),mip1: I suspected a dying battery
Yes - very good plan if they are original (check the stamped date on the -ve battery posts). It could also be the Power Supply Controller or the alternator/dynamo or whatever the technology is on the V10. But you can't really get on to analysing these without replacing the battery first.
This morning I replaced both batteries on my V10. I needed to remember my Health & Safety lifting training, try and remember how to be moderately strong, agile enough to kneel in the boot, and have 3 arms (I got a friend to help). And checked the threads on what to dismantle... although many pictures are missing at present. There were a load of scan 'faults' afterwards, so it's handy to use a VCDS to clear them after things settle down again.
The batteries were original (June 2005) and held their charge well, but you probably saw my posts about various 'faults' being logged. I am hoping that the lower internal resistance of the new G14 battery will stop the Low Voltage flags during the moment of start-up. And fingers crossed for the turbo 'fault', although the jury's out on that one.
I will report what happens, but from the experience of others I would definitely suggest replacing your LH battery. And if the LH one is sagging because of age, then the RH one is probably also drawing a different charge current profile from when it was fresh, and that comes from the vehicle starter-battery-charger fed off the LH battery system, which won't help things. So that's why I replaced the RH one as well, although engine cranking was impressive on the old battery.
It's still possible you have a controller staying awake though - but maybe the very low voltage you are experiencing is disabling it's sleep mode, so the problem goes round in circles?
read the signature at the bottom of Mip1's post!! Guess lifting those batteries has done your eyes in!!
Guess you got pretty good service too from "my" supplier! Also worth noting that there is a company about 1/2 mile away from them that supplies the REQUIRED Fuchs oil, now that Castrol have stopped supplying retailers!
Just a small update about the LH battery voltage. Wouter dropped by the other day with his V6 TDI and of course I did some measurements.
After opening the trunk lid, the calibrated DMM showed 12.6, rapidly dropping to 12.4...12.2 V when Wouter switched on the ignition. His dash meter indicated an identical reading.
Shortly after ignition, the DMM reading went above 14 Volt, 14.2V to be exact with an occasional peak to 14.4 V. His dash meter again showed the same reading.
My own W12 showed 12.1 Volt with ignition on and 13.85V with running engine. This left food for the thought that my generator might be faulty. Impossible IMHO, because when I switch on heavy power users, like the window defroster or the head lights, the voltage doesn't change a bit.
My battery charger control module is version C (3D0 915 181 C) and firmware is 2700, so that should be OK. Given the fact that I'm not tortured by any electrical gremlins, there doesn't seem to be a need to do something about it. I guess that these charger controllers do have some tolerance, i.e. some charge at higher voltage than others as the result of variations in the manufacturing process.
I hope to check more Phaetons in the future. And to measure the charge current, which I forgot to do this time.
Willem - your 13.9V is odd given most other readings reported seem to be over 14V.
I've got a spare used 6 year old LH battery now... haven't yet deceded what to do with it. It's been off the vehicle for 5 weeks. Measured its oc voltage yesterday. Very odd behaviour. But maybe because I'd moved it immediately before measring, but the DVM measured about 13.9V but it rose as I watched it over about 20s to 14.2V. And it's been there steady ever since.
Really can't understand why it would be so high.... another question about the accuracy of my DVM.
I'll keep teasing away at this off an on.... when it stops raining!