Battery Drain

For the M Powered Z3 derivatives

Moderator: Gazza

Post Reply
Chazzy
Joined: Wed 16 Jul, 2014 10:04
Posts: 23

  M roadster S50

Battery Drain

Post by Chazzy » Sun 17 Apr, 2016 19:42

I can't leave the car for more than about two weeks without the battery completely draining. I'm also having issues with the alarm so I'm wondering if the two are linked. Has anyone had similar issues or know what it could be?

swamper
Joined: Thu 13 May, 2010 18:14
Posts: 1866

  M roadster S50
Location: Mossley

Re: Battery Drain

Post by swamper » Mon 18 Apr, 2016 22:03

the obvious question Chazzy is have you changed the battery?
i had a fault on my Z3 that was doing the same and it turned out to be the seat motor was slightly switched / stuck on but not enough that you would notice
the badness makes me do it...!

Image

Alan W
Joined: Thu 20 Jun, 2013 11:56
Posts: 668

  Z3 roadster 2.8
Location: Bexley, Kent UK

Re: Battery Drain

Post by Alan W » Mon 18 Apr, 2016 22:19

My car had the same issue so I kept it connected up to a trickle charger when not in use. The other day I started the car and pulled it out on to the drive and it was running for a while so there was no reason to think that there wasn't any juice in the battery but when I went to start it a few hours later it was as dead as a dodo, so I put a new battery on and its now as right as rain. Around 5 years is the accepted life of a battery so unless yours is a lot newer do yourself a favour and get a new one or risk breaking down at night when its p***ing down.. I paid £49 for a heavy duty Exide also meant for diesel transits.
1999 facelit Z3 Roadster 2.8 Auto in Cosmos Black aka 'Gloria'
Image

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10010

  Z3 roadster 1.9
Location: Cheshire

Re: Battery Drain

Post by Robert T » Mon 18 Apr, 2016 22:30

If a battery is kept in good condition and never allowed to go flat, then is should last a lot longer than 5 years, but it depends very much on the battery and how you use the car. My first US battery failed under warranty, and was replaced with one from BMW Germany. That battery is still on the car and doing daily service, no trickle charger, and very little maintenance. It is getting on for 15 years old now, so I think you can say I've had my money's worth out of it (it was free). My zed is my daily driver and although it generally does a lot of fairly short journeys, it also gets some good long motorway runs as well.

Regarding the battery drain, you need to check the usual suspects, such as an interior light that is stuck on, or a short circuit in the boot loom (though that tends to blow a fuse). You don't say what your alarm issues are, but the alarm will drain the battery quite quickly if it keeps going off. A flat battery can also cause problems with the alarm, like not responding to remotes. You can put an ammeter into the circuit and see what the current drain is with everything off. If this is high, then you can pull fuses one at a time until you find the culprit. Then you can go through all the items on that fuse and eliminate them. As suggested a duff seat switch causing the seat motor to try to run continuously will certainly drain the battery quickly and is worth a quick check, but it is by no means the only cause of battery drain.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 803

  Z3 roadster 1.9

Re: Battery Drain

Post by mrscalex » Tue 19 Apr, 2016 09:56

I have a brand new heavy duty Exide on the car and it overcame a lot of starting problems.

But I left the boot lid up for a few days in the garage and the battery was completely and utterly flat, not a peep, when I went back to it. So I guess it was that little boot light that did it but still surprised.
ImageImage
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

User avatar
Buz007
Joined: Fri 16 Jul, 2010 21:18
Posts: 244

  Z3 roadster 1.9
Location: Leeds

Re: Battery Drain

Post by Buz007 » Tue 19 Apr, 2016 10:31

Hi there, I've gone back to my z this morning after being garaged for 7 months, I left the alarm on (stupidly) and all im getting now is a ticking sound when turning the key....Am I correct to assume I've killed my battery???? hoping beyond hope its not a complex immobiliser issue!

Thanks
''need I remind you 007, you have a licence to kill...not to break the traffic laws''

mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 803

  Z3 roadster 1.9

Re: Battery Drain

Post by mrscalex » Tue 19 Apr, 2016 11:40

Buz007 wrote:Hi there, I've gone back to my z this morning after being garaged for 7 months, I left the alarm on (stupidly) and all im getting now is a ticking sound when turning the key....Am I correct to assume I've killed my battery???? hoping beyond hope its not a complex immobiliser issue!

Thanks
Put it this way. The battery is the first thing to try and you'd be unfortunate if it wasn't that.
ImageImage
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

User avatar
Robert T
Site Admin
Joined: Mon 12 Jun, 2006 11:35
Posts: 10010

  Z3 roadster 1.9
Location: Cheshire

Re: Battery Drain

Post by Robert T » Tue 19 Apr, 2016 18:10

Ticking noise tends to mean there is some life in the battery, just not enough to start the car and it won't even try to engage the starter motor. If it makes no noise at all, then it is pretty much dead and much less likely to recover if you charge it. Batteries do not seem to like being drained completely.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
Image

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests