Tambohamilton

Installed part was 1K8 951 605A, but I assume that was just a revision change and nothing fundamentally different from the B part? Good to know that LLL is probably the best for it - I've used them before. Thanks

Finally got around to doing this on PC instead of mobile - worked straight away with copy/paste. Unsurprisingly the manual/fuse diagram is identical to what is in the car, so that doesn't help, but never mind! New battery seems to be holding fine, so I'm pretty much assuming that the dead alarm module battery killed the last 2 starter batteries. I'll continue to keep a vague eye on it for a while yet though. Where would be best/cheapest for me to buy a genuine alarm module? I'm not keen on messing with a pattern part, and the hassle they bring.

New battery is in. It's dropping about 0.1v overnight (12.9-12.8). I assume that's OK because it's over 12.7; it's not really losing significant charge (and way over any danger voltage)? Still, more of a downward trend than I'd hoped.

Thanks. As is typical, it doesn't recognise my vin. But is an 11 reg car and the late 2010 manual doesn't stack up, so it must be the "2011/5" manual. I wonder if the car is just really close to the crossover date (hence new fuse layout but old manual), or one of the POs replaced the manual for whatever reason... Anyhow, at least now I have a better reference for fuses! Beginning with the 2011/5 manual, they no longer list fuse ratings. Can't have it all, I suppose! New battery due to arrive today sometime...

Great, thanks for this. Nice to see fuse 39 actually listed! Where did you get it, if you don't mind me asking? Am I right in guessing that it's just a generic diagram for the later model MK2s? Where would I find info that is specific to my car?

No coding required - dumb dumb alternator. Will certainly keep an eye on it when the new one goes in.

Yes, because I really don't want to put a new battery on it, only for it to get destroyed like this one has been. Issue isn't reading the card or manual - they're wrong/incomplete, so I'd just like to have the correct information for this car. I know the battery is done for - replacement will be arriving in the next few days. The only question I need to work out right now is whether parasitic draw remains with the (very dead) alarm module removed, or whether the overnight voltage drops are just because the battery is toast. Simple solution but I just haven't had time: disconnect the battery from the car and see if the voltage still drops the same. And/or directly measure the current draw at the battery with the car asleep. Thanks for the replies, I'll keep the thread updated with any developments...

The battery is about 3 years old. Varta. Parasitic draw has always been an issue, though it took me a while to recognise it. When she bought the car it had a connector attached to the battery terminals - clearly a quick connector for a charger, but I failed to join the dots. We replaced the original battery soon after buying because it seemed weak. And if the car was left for a week or so it would be weak too. In the past month or so it's got to the point that it needs to be kept on charge overnight, and like I say it'll struggle to start with anything under 12.4v. So I'm 100% sure there is a parasitic draw - or at least was until I removed the alarm module. Good to know regarding the sleep thing - wasn't sure if it would go to sleep with a door open. Is there anywhere I can pick up a reference for the fuse layout on my car? I don't really trust it now, knowing the book is wrong.

Spot on, that's great, thanks. Regarding the sleep...I haven't. Right now I'm just looking for anything that's drawing current with the car off/doing nothing. Fuse 39 is the only thing so far (other than alarm module, now removed). I think the next trick will be to rig up a remote fuse holder, so I can test it again with the car asleep, I think. And to investigate the instrument cluster and j527 superficially. I know the (starter) battery is goosed right now, but even with the alarm module out it's still dropping from 12.7 - 12.5v overnight...and just manages to start the car from 12.4v. The voltage drop is steady through the night, so whatever's drawing current is doing it constantly. Thanks a lot for the help so far!

Thanks! TMBBJ21Z0B2091602 Is it possible you can give me a full list of the fuses, please?

Pic of the fuse box as it stands;

Hi all, Chasing parasitic draw on my partner's 2011 Octavia 1.4TSI. I've ruled out the alarm siren - removed it yesterday, and the battery had drizzled acid all over the PCB. Waiting to get a new one now. The draw still seems to exist, though maybe a bit better than before I took that out. I decided to measure voltage drop across the fuses. Found a couple at 0.2-0.3mV; normal safe range. And one fuse at 2.2mV (about 150mA of current, approximately). It's fuse #39, 5A (I've double checked the fuse numbering, as that's confusing). According to the card by the fuses, I should read the manual about fuse 39. According to the manual it is not assigned! So I guessed it wasn't supposed to be there at all and pulled it; the clocks went off (time reset etc). Now according to the manual, the fuse for the clocks should be #6. I pulled that one and it also causes the clocks to lose power. So how can I figure out what fuse 39 is up to?

Yeah, using a bm2 monitor on it, so I can track the voltage over time, and measure it without waking the car...but it doesn't measure current, which would be super useful!

Thanks. 100% certain there's no button, and 99% certain there's nothing extra on the neg terminal. So I'm pretty content that I haven't nuked the battery by charging it inappropriately or something like that.

You deal with a lot of dead batteries! The car doesn't have a battery monitor, I'm 99% sure. I'll check properly next time the bonnet is open. It certainly doesn't have start/stop. I'm guessing that's why my coding options for the battery are so limited; it literally doesn't need to know what the chemistry of the battery is, because it won't do anything differently.