Battery drain?
 

Gents,

The battery on my S8 has completely flattened a couple of times now in the space of 4 weeks. In between, I bought the AA solar conditioner, but forgot to plug it in, after its last use on Monday afternoon. :rolleyes:

This evening, it's completely flat - can't use the blipper, no lights on dash, no nuffink.

Somewhat coincidentally (I think) on both occasions, the car has been parked on a slight downward incline, perpendicular to the kerb, left side down. We live in purpose built flats with shared parking slots, so don't always get to park where I want, ie in front of the flat and on a level.

Probably nothing, but is there anything that could be left enabled, by parking on an incline ? I'm thinking of maybe the alarm module, is there a tilt sensor perhaps?

It's also entirely possible the battery was screwed after the first time, hence its failed again so soon, although I did leave attached to the the CTEK overnight.

Anything i can test via VCDS?

Cheers folks

D2 or 3

D2

Not familiar with them but there is a vw file I have on computer about checking voltage drop across fuses, attached for you

Yes this is entirely possible. If you run battery flat enough that it does not start the car it will damage it. If you run it flat enough that dash lights don't come on you will damage it a lot, if you leave it at this discharged state for week it will be pretty much unusable.

How many amps is your charger? 5 amp CTEK charger will take about 20hrs to charge good fully discharged 100Ah battery to 80% and then another 25-30hrs to get to 100%

There are no commonly known issues that will drain battery in D2, parking on incline should not affect it unless you have blocked plenum chamber drains, it could cause water to overflow in rain and leak onto electronics so parking on incline could be a factor if or where the water will come in. Only thing VCDS can check on D2 is voltage.

You could go to Halfords and ask them to check battery condition for you they normally do it free of charge.

You might also want to check residual drain current from battery with everything off.

Another possibility is poor ground or positive connection for for battery which could lead to less current going through and slowing the battery charging when running and giving less current when cranking. You can check this by comparing voltages measured directly on battery, battery + to ground and + at the front of car to ground.

Thanks both for your assistance.

I have the 5A Ctek and charged it to 80% as I had to drive the car the next day. I'll remove it tonight to give it a full recondition charge.

I've not checked the plenum drains since ive bought it but did clear the 2 wheel arch drain just after xmas. You could be onto something there as if there was any water in that area, it would drain towards the ECU etc the way i parked it.

I may call the RAC out to do a load test on the battery. If all is well, will attempt the residual drain test.

I've never known such a difficult battery to remove from a car, what a ridiculously sized compartment.

Does your battery have handles, it should?
I've changed a D2 battery before and it wasn't difficult at all and I'm definitely NOT a mechanic.
Bit tight and the cables needed care to get out of the way but that's all.

Yes just the tightness of the cables really - next to zero movement in the cables makes re-seating the battery pretty difficult

It's been a while, but I think I used bits of string and duct tape to help keep the cables under control. :ROFL:

And IIRC there may be a vent pipe from the battery as well, depending on type.

I was worried I had a current drain somewhere so I bought one of these.
Its not terribly accurate but should be good enough to pick up a serious drain somewhere, and its cheap compared to the highly accurate meters which go into the hundreds of pounds.

http://www.maplin.co.uk/p/uni-trend-...mp-meter-n41nc

Its DC voltage resolution is 0.01A and accuracy is 2%+5 units (0.05A) up to 40A range.
So if you had a normal parasitic drain in the D2 sleep mode of around 0.1 to 0.2A the reading could be +/- 0.05A out but the error is small enough.
So for example if your parasitic drain turns out to be 0.4A you will know that's too high, even with the +/- 0.06A error its still too high.

My car's reading was 0.18A and it does not kill a 31Ah battery after 10 days. So in my case the reading may be a bit high as at that rate it would drain 43Ah in 10 days.



stats here

http://www.uni-trend.com/en/product/2014_0730_827.html