In the two months I've owned the car it's had a full service, a new dipstick, haldex and DSG oil changes, 4 new tyres, new water pump, cam belt, and auxiliary belts. I'd really like to think the car is in a good state now and I can stop worrying about it. Except now there's a problem with the battery, which is only 1 year old. It wouldn't start the other day so I had to remove the battery and charge it up. Last night I drove it and checked the charge when I got home. 12.65v, so that looks good. In the 18h since then it had lost charge and is now at only 11.80v.

 

Any common problems I should look at?

Does yours have the TV as when (mine 2012) had to have a software update due to the Columbus and TV sometimes but not always allowed a run on of the cooling fan (not coolant system) for more than 20-30 minutes instead of 2-3 minutes. The current draw on that of not just the fan but the control units as well was quite a few amps. Sorry I can't be more accurate but it was around 2014 and the VW recovery people were well versed on the subject.

Then again it might be something completely different.

I ended up with a software update and new battery. 

Edited 26 February, 20188 yr by Danny 57

3 minutes ago, Danny 57 said:

Does yours have the TV as when (mine 2012) had to have a software update due to the Columbus and TV sometimes but not always allowed a run on of the cooling fan (not coolant system) for more than 20-30 minutes instead of 2-3 minutes. The current draw on that of not just the fan but the control units as well was quite a few amps. Sorry I can't be more accurate but it was around 2014 and the VW recovery people were well versed on the subject.

Then again it might be something completely different.

I ended up with a software update and new battery. 

 

Hi Danny,

 

Yes it does have the TV. Is the fan/control unit the box in the boot? It does run briefly when the car is off for some reason, seems to be related to me opening the boot, so could be that...

 

Not sure why it would be a problem now when it wasn't before though.

My problem only started after 18 months to 2 years, no idea why either.

Edited 26 February, 20188 yr by Danny 57

 

10 minutes ago, Danny 57 said:

My problem only started after 18 months to 2 years, no idea why either.

Thanks Danny that's really helpful to know. Well worth me exploring the possibility. Don't suppose you (or anyone else) knows which fuse drives the TV tuner in the boot? I plan to pull it and see if that stops the drain.

I have meant to look for that fuse myself as my car has been a bag of (brown) since day one with flat battery problems.

Blade group had it many times but kept saying it was fine, they had no idea why the tv tuner fan stated up each time the boot opened and seemed to not care.

I had thought I had cured it (as stated on another thread)by updating the Columbus firmware but after a few weeks the battery started flattening again.

As we speak the battery has not gone flat for over two months, scared to say it is fixed but it has never gone more than two weeks without needing to be jump started.

If it is fixed it is down to my independent mechanic who fitted a heavy cable from the engine to the negative battery terminal.

 

All analysis before this fix showed no fault, charging voltage etc. was correct, however I have noticed since the cable was added that the charging voltage can 0.2 volts higher than it used to be (was always 14.2) so that seems to be an indication things are different.

I have even dared to use the seat heaters, not that they work fast enough to bother with .

21 minutes ago, superbdreams said:

I have meant to look for that fuse myself as my car has been a bag of (brown) since day one with flat battery problems.

Blade group had it many times but kept saying it was fine, they had no idea why the tv tuner fan stated up each time the boot opened and seemed to not care.

I had thought I had cured it (as stated on another thread)by updating the Columbus firmware but after a few weeks the battery started flattening again.

As we speak the battery has not gone flat for over two months, scared to say it is fixed but it has never gone more than two weeks without needing to be jump started.

If it is fixed it is down to my independent mechanic who fitted a heavy cable from the engine to the negative battery terminal.

 

All analysis before this fix showed no fault, charging voltage etc. was correct, however I have noticed since the cable was added that the charging voltage can 0.2 volts higher than it used to be (was always 14.2) so that seems to be an indication things are different.

I have even dared to use the seat heaters, not that they work fast enough to bother with .

Interesting. I can't figure out which fuse it is from the user manual. I can't see any logical reason why the tv tuner fan would need to blow when the boot is opened. Maybe the mechanics of the boot opening/shutting connects something when it shouldn't? Damaged wire? I don't know, but given you have it, I have it, Danny had it, and this RAC guy had seen it a lot, it seems likely to be related to that. Also interesting about the grounding cable you had fitted, might try that if I cant get anywhere figuring out whether it's this tv tuner.

29 minutes ago, superbdreams said:

All analysis before this fix showed no fault, charging voltage etc. was correct, however I have noticed since the cable was added that the charging voltage can 0.2 volts higher than it used to be (was always 14.2) so that seems to be an indication things are different.

I have even dared to use the seat heaters, not that they work fast enough to bother with .

 

Why would a bad engine earth cause battery drain issues? It seems to have improved charging though

Edited 26 February, 20188 yr by SuperbTWM

I just checked the TV tuner to see if I could unplug the cable from the back but can't see how to remove the tv tuner to get proper access. I can feel a cable on the back but can't see what I'm doing.

 

Anyone know how to get it out? Can't see any screws. Wonder if it is glued in place.

 

p.s. as usual, the tuner's fan came on while I had the boot open. 

In my current supposed fixed state the fan still starts with the boot opening.

10 minutes ago, SuperbTWM said:

 

Why would a bad engine earth cause battery drain issues? It seems to have improved charging though

Exactly that, I am supposing that the current now available at the battery is also increased, further speculation is that there is a high resistance through the OEM engine strap (which I have still not found BTW)

45 minutes ago, snowathlete said:

I just checked the TV tuner to see if I could unplug the cable from the back but can't see how to remove the tv tuner to get proper access. I can feel a cable on the back but can't see what I'm doing.

 

Anyone know how to get it out? Can't see any screws. Wonder if it is glued in place.

 

to answer my own question, my husband thinks I need a special part. T10057 to remove it. How annoying. He thinks he might be able to take the cable out the back without removing it though, see if that fixes the drain or not.

5 hours ago, snowathlete said:

Except now there's a problem with the battery, which is only 1 year old

Any common problems I should look at?

 

What sort of battery is it? Presumably as yours is a facelift it may have stop/start - if not fitted with a suitable (replacement!) battery for this then it will fail quickly due to the regenerative charging. It needs to be  AGM(Absorbant Glass Mat) or EFB (enhanced Flooded Battery) . If the battery is iffy then cold weather will finish it off.

 

Edited 26 February, 20188 yr by bigjohn

6 hours ago, snowathlete said:

 

Thanks Danny that's really helpful to know. Well worth me exploring the possibility. Don't suppose you (or anyone else) knows which fuse drives the TV tuner in the boot? I plan to pull it and see if that stops the drain.

 

I have just looked at the report from 040714, which states. "Battery drain of 2.2A causing flat battery. Removed fuse (F8 if I have read his writing correctly) for Nav unit and drain virtually disappeared to 0.02A" He further states ""Requires new Columbus unit".

Edited 26 February, 20188 yr by Danny 57

2 hours ago, bigjohn said:

 

What sort of battery is it? Presumably as yours is a facelift it may have stop/start - if not fitted with a suitable (replacement!) battery for this then it will fail quickly due to the regenerative charging. It needs to be  AGM(Absorbant Glass Mat) or EFB (enhanced Flooded Battery) . If the battery is iffy then cold weather will finish it off.

 

 

It's not an AGM as it came with when new, but we always turn S/S off so I don't think it should cause the battery to fail any sooner. I'm pretty sure something is draining it but I'll test it in the next day or two to find out for sure. If something is draining it then I guess I'll have to start pulling fuses to identify the circuit. I'm wondering if there are any circuits that I should leave alone though; if there are any that would react badly to having their juice cut off briefly?

10 hours ago, snowathlete said:

 

It's not an AGM as it came with when new, but we always turn S/S off so I don't think it should cause the battery to fail any sooner. I'm pretty sure something is draining it but I'll test it in the next day or two to find out for sure. If something is draining it then I guess I'll have to start pulling fuses to identify the circuit. I'm wondering if there are any circuits that I should leave alone though; if there are any that would react badly to having their juice cut off briefly?

 

You said the battery was only one year old in the original post so how can it be the original battery? 

Also it's not the fact you turn off S/S - the charging is different to pump back regenerative current quickly, standard batteries can be damaged or even explode. Also unlike with the Superb I the batteries are somewhat under specced so can fail prematurely.

 

However presuming it's current drain @Wino posted a very useful table to measure mv across different fuses without disconnecting to determine current draw, attached: -

 

EDIT, found the post:- 

 

 

 

vw.current.draw.tb.pdf

Edited 27 February, 20188 yr by bigjohn

4 hours ago, bigjohn said:

 

You said the battery was only one year old in the original post so how can it be the original battery? 

Also it's not the fact you turn off S/S - the charging is different to pump back regenerative current quickly, standard batteries can be damaged or even explode. Also unlike with the Superb I the batteries are somewhat under specced so can fail prematurely.

 

However presuming it's current drain @Wino posted a very useful table to measure mv across different fuses without disconnecting to determine current draw, attached: -

 

EDIT, found the post:- 

 

 

 

vw.current.draw.tb.pdf

 

I think I confused you somehow, sorry, it's definitely not the original AGM battery, it's a one year old lead acid battery installed by the previous owner. Higher spec than the original, but obviously no S/S technology. Specifically it's one of these:

https://www.batterymegastore.co.uk/varta-e38.html

 

That's good to know about the extra charging, I had assumed it would only charge faster if the battery management system detected a drain like you'd see if S/S was used. I have it on my list to change the battery for an AGM when the current battery fails but pretty much decided to wait until it did. That could be now of course. We'll try and diagnose the problem. Thanks for that post that looks super handy.

 

 

Looks like there's about a 400 milliamp draw from somewhere. Husband tried to disconnect the TV tuner but says he can't without removing it. He tested the voltage drop on each of the fuses except the very large ones and all looked normal so we're not sure what's going on. He's going to drive it then turn it off and check the voltage drops again, thinks maybe something (perhaps the TV tuner) is taking too long to power down.

Edited 27 February, 20188 yr by snowathlete

3 hours ago, snowathlete said:

Looks like there's about a 400 milliamp draw from somewhere. Husband tried to disconnect the TV tuner but says he can't without removing it. He tested the voltage drop on each of the fuses except the very large ones and all looked normal so we're not sure what's going on. He's going to drive it then turn it off and check the voltage drops again, thinks maybe something (perhaps the TV tuner) is taking too long to power down.

 

400milliamp could be just the fact you have the door open to check the fuses. When drivers door is open , as well as the interior light being illuminated all sorts of things start firing up - eg fuel pump

 

 

 

14 minutes ago, bigjohn said:

 

400milliamp could be just the fact you have the door open to check the fuses. When drivers door is open , as well as the interior light being illuminated all sorts of things start firing up - eg fuel pump

 

 

 

Plus 1. Two interior lights at 5w each is nearly 833mA. Just for those that do not know I=W/V. Unless I have got it completely wrong and now look a fool.

25 minutes ago, bigjohn said:

 

400milliamp could be just the fact you have the door open to check the fuses. When drivers door is open , as well as the interior light being illuminated all sorts of things start firing up - eg fuel pump

 

 

 

When this was measured earlier in the day the doors were all shut for ten minutes before measurement taken, only the bonnet was open and the car had stood overnight.

 

After a 15 minute drive the battery was up at 12.5V. Battery showed 0.096A draw immediately after the drive, but car had not had more than a minute to go to sleep so doesn't tell us much. An hour later it's down to 12.22V and this time the draw on the battery looks normal at 0.016A.

 

Fuses in the engine bay all look fine. 

Fuses in the dash may be fine too as the door had been opened. The door latch was manually shut but we think the fuses showing power are all related to things that maybe take ten/twenty minutes before they sleep? Here they are:

 

14 central locking and bonnet lid (bonnet lid still open so that's fine) - 0.06mV

15 central control unit - interior lights- 0/16mV (interior light switch set to off, but still probably normal)

18 phone - 1.9mV (it's presumably searching/connecting/disconnecting the blue tooth while car stopped but not locked)

22 air blower for climatronic - 0.69mV (I guess it's ready to blow air if you want it to even though the ignition is off?)

 

Fuse F8 in the engine bay is for the radio and looked normal. Presumably this covers the TV Tuner as well? If that's correct then it looks like the TV Tuner is fine, unless there is an intermittent problem going on.

 

Going to test the load on the battery again tomorrow. If normal then I guess we'll order a new AGM battery and keep an eye on it. 

Edited 27 February, 20188 yr by snowathlete

I was thinking:

Take the battery out. Charge it from the mains. Disconnect and leave it to sit over night and check the charge in the morning to see if it's dropped. That would confirm if the battery is screwed or not.

Before I do that, will any systems on the car, like the radio, lose memory if the battery is removed for a long period like that?

1 hour ago, snowathlete said:

I was thinking:

Take the battery out. Charge it from the mains. Disconnect and leave it to sit over night and check the charge in the morning to see if it's dropped. That would confirm if the battery is screwed or not.

Before I do that, will any systems on the car, like the radio, lose memory if the battery is removed for a long period like that?

 

After charging you'd need to leave outside in the cold to compare - possibly for longer as your mains charger may warm the battery up more!

 

If it was myself I'd just go and buy the correct battery anyway if your going to bother taking it out! Basically I think your battery is on the way out anyway and the cold weather is showing this up!

 

Radio code should be stored in the cars CPU so should come on after a while

Edited 27 February, 20188 yr by bigjohn

58 minutes ago, bigjohn said:

 

After charging you'd need to leave outside in the cold to compare - possibly for longer as your mains charger may warm the battery up more!

 

If it was myself I'd just go and buy the correct battery anyway if your going to bother taking it out! Basically I think your battery is on the way out anyway and the cold weather is showing this up!

 

Radio code should be stored in the cars CPU so should come on after a while

 

Could do but if I do that and it turns out not to be the battery then the new battery'll have the same problem plus I'll be down the cost of the battery.

Although it's dark, I just checked and there's a similar draw on the battery to earlier today when I first tested. So it does seem likely there is something draining it, just can't figure out what. Didn't check the fuses again this time but they looked ok earlier. Don't think there is anything after market on the car not going through the fuse box, perhaps the towbar?

52 minutes ago, snowathlete said:

 

Could do but if I do that and it turns out not to be the battery then the new battery

 

Yes- but I think you have the wrong battery fitted, you may have other problems with this!

http://blog.greenflag.com/2016/cheap-batteries-costing-drivers-with-start-stop-cars/

 

It's very hard to get to the bottom of battery drain on a CAN bus car as disconnecting and reconnecting things trigger all sorts of strange current flow hence the fuse tests although most of the Superb fuses need a door open.

 

As the Satnav is a know current drainer it's worth starting there. I've found a reasonable quality clamp meter very good for this sort of thing (not clamped around "+" and "-" as they cancel each other out)

Edited 27 February, 20188 yr by bigjohn