Battery going flat overnight

[vwforever]

Hi Can anyone give me some ideas

I have an 05 new shape passat which the battery is draining enough overnight not to be able to start it

1 New Battery in Febuary
2 putting in plenty of power
3 There is excessive current drain taken every fuse out one by one checking draw and there no major drop on fuses
4 no lights on dash or interior lights staying on

It has be to a local garage twice and both times its comes back it has been no better

I have been told now that it may be the diode in the back of the alternator gone which is causing to to carry on drawing current while its swiched off

Has anyone had this problem or point me in any direction

Thanks

[martin1810]

Have you changed the radio as this is a common problem with radio upgrades. If not then take the (+) terminal off the battery and connect an ammeter betwen the (+) battery terminal and the lead. It should read less than 200mA on most cars. If it is more, start pulling out fuses one at a time and putting them back. See if any of them cause the current drain to drop. If none of the fuses seem to have any effect, disconnect the wire that goes to the alternator. If that works, the alternator diode pack has gone wrong.
If none of this makes sense....call an autoelectrician.

[DSG4ME]

Alternator sounds feasable to me as well, if the car is 4 yrs + or over 80k, you can expect the unit to be failing, a recon is the cheapest solution btw, try GSF, Euro Car Part's and your local motor factors for one,and expect something like £130-£190 exchange for one, VW will want £400 ish, hth.

[patomlin76]

May be stating the obvious, but you haven't upgraded the head unit recently?

[DSG4ME]

May be stating the obvious, but you haven't upgraded the head unit recently?

What is the problem with upgrades? is it just VW ones or aftermarket ones causing problems?

tia.

[patomlin76]

mainly it's the newer RCD 310/510 models supplied with 09+ models - when installed in earlier models they drain the battery pretty quickly. The solution is to have the canbus system firmware updated.

paul.

[Flash2]

Hi Can anyone give me some ideas

I have an 05 new shape passat which the battery is draining enough overnight not to be able to start it

1 New Battery in Febuary
2 putting in plenty of power
3 There is excessive current drain taken every fuse out one by one checking draw and there no major drop on fuses
4 no lights on dash or interior lights staying on

When you say the battery is going flat overnight, how do you get the car started? How do you recharge the battery? What type of driving do you do (a lot of stop/start cycles?).

Also, how did you measure the excessive current drain? Did you disconnect the battery and connect an ammeter in-line as martin suggested? If so, how long did you leave the meter connected? It takes approx 5 mins for all the electrics to shut down again after the battery has been reconnected, so just putting a meter in-line and taking a reading straight away will show an excessive current drain. Just something to be aware of.

Regards.

Jim.

[redrolo]

mainly it's the newer RCD 310/510 models supplied with 09+ models - when installed in earlier models they drain the battery pretty quickly. The solution is to have the canbus system firmware updated.

paul.

The issue is on the cars that are pre MY2008 and covers not just the RCD310/510 but also the RNS510. The canbus adapter does not recognise the switch off requirement of the above stereo units, and so drains the battery. There are 2 solutions:

1. downgrade firmware on the unit to 1100 or less, although this limits the possible additional features, so voice recognition, cameras etc are not possible.
2. The more favoured way is to get a new updated canbus adapter, of which there are lots available and people willing to fit them around the forums.

[Meds]

And there was me thinking about upgrading my Radio/Cd player unit ... it would seem that its an original fit unit RC300 unit?

I was eyeing up an upgrade for my recently acquired 2006 B6 Se ... the units that interest me are the ones that will play a single CD/Radio function and has SatNav.

I have seen a few units around the £275/£300 mark on eBay.

Having read this thread, I now have some doubt if the units I have been looking at would be compatible.

Could anyone suggest a specific unit that would do the above? ... and if I have the gist of this thread right, I'm assuming that I will need to purchase a new canbus adapter and have it fitted and (? reprogrammed) ... any help much appreciated ta

[redrolo]

You can get aftermarket unit of various types which don't need the same canbus upgrade as a 'newer' OEM VW unit but may cost you a few quid. I would stay away from some of the ones you see on Ebay, unless its a name you recognise.

For an aftermarket stereo, you need to decide whether you want single or double din as your size. Single din is the 'traditional sized unit' and double din is the same size as your Passats. Then you need to get the appropriate fascia surround and iso connectors to fit to the Passat. Also need to make sure you have the right aerial connector.

You can get a MFD2 unit similar to the attached which will go onto your car without the upgraded canbus adapter which is the cd/satnav for your year of Passat.

http://cgi.ebay.co.uk/VW-sat-nav-MFD...item439ecbada2

Or you can get the canbus upgrade and get:

RCD310 - (Updated version of the RCD300) with some more features

RCD510 - Inbuilit 6 disc variant of the above

RNS510 - Newer SAT NAV/CD combo. 3 versions available, AB and C, with C being the latest updated model.

With the newer units there may be some work needed with the vagcom settings.

There are arguments on the forum for which way to go, but like everything it is your choice.