Battery drain

[CraigTas]

Hi all, have got tons of good info over the years off VWwatercooled (thanks) but decided to join as I'm in need of help.

I'm a happy owner of a 2005 2.0 FSI Golf I bought used a few years ago (has about 150K on it). I love it's straight forwardness - it does what it says on the tin.

But about 18 months ago I started getting a flat battery - sometimes to level of no electric door unlock and others just not enough to crank the engine over. It appears I've got a parasitic drain. When issue continued took it to battery shop and of course they sold me a new one. But issue has continued. There's no electrics being left on, I have neighbours on all sides and one of us would've noticed if lights/wipers or anything obvious was turning on at night. Unfortunately it's intermittent as can leave at airport for 3 days with no problem but other times will be flat after one night (12 hours since last drive).

Sometimes there's just enough juice to crank the engine and it starts so I can drive to work. I only work 8kms from home and strangely the car will start no problem at all for days straight after that. So am assuming the battery is getting the required re-charge when driving even a short distance.

My mechanic, a great guy who only does VWs doesn't do auto-electrics and couldn't help. As it's intermittent (can go weeks without happening) I can't see how an auto-electrician could help unless I can isolate the issue.

One thing puzzled me the other day (last time it happened) - was enough juice to auto-unlock car but when I turned ignition I got about a half a crank and then dead. But all the dash meters/counters and clock had zeroed (not radio) - but surely if there's enough juice to even only half crank an engine there'd be more than enough for the memory on the counters and clock to survive - is this a possible indication of where the problem is?

The car is stock factory standard. I did put a bluetooth phone unit in (hooked up to the VW CD/radio unit) but that was three years ago and problem only in last 18 months. Weather, wet/dry or hot/cold seems to have no effect on problem.

If anybody has any suggestions I'd welcome it. I'm no mechanic but reasonably practical and a logical mind but wouldn't know first thing about auto-electrics beyond where the fuse box is.

Appreciate any help, thanks

[Gold Coaster]

If you have a digital amp meter then this youtube video may help?
http://https://www.youtube.com/watch?v=KF1gijj03_0

Not sure why the link isn't working but if you go to youtube and type 'How To Perform a Parasitic Draw Test - EricTheCarGuy' into the search box you'll find the video that I'm referring to.

[CraigTas]

Thanks Gold Coaster - the video was very helpful and makes complete sense. I need to make the car go to "sleep" and various sites say 30-120 mins. But I need to get under the hood and also have driver's side door open to access both fuse boxes. Do you know if there are sensors for door closed or can I just use a screwdriver to trigger the door and hood latches? Read something about a hood pressure sensor - any ideas?

I also read on another site that pulling fuses is inconclusive as the act of pulling a fuse can 'wake-up" the system. Found this VW Tech bulletin about using Voltage drop as alternate method. http://pics.tdiclub.com/data/500/TSB..._04_Matrix.pdf

Anyway I'll try both and see if results agree. Thanks for help and will post results. Trouble I have is finding time with the car being kid's taxi

[Umai Naa!!]

Close the latches with a screw driver, and lock the car.

It will go to sleep after approximately 20mins.