More Z4 Woe

M

mattb10

Member
Hey guys,

I actually feel pretty bad because whenever I post on here it's always to ask for help and guidance. I feel a bit of a user..! :wink: But at least that's testament to how much I appreciate everyone's help on here :D

If I may, I'd like to ask a few questions so I have a better idea of what's going on with my Z4. But first, a bit of back story. On 09 December 2014 I changed the battery over and the car went into Transport Mode (as someone called it). Basically the fans weren't working in my case.

Now I must admit I've been very neglectful of my car over the last few months whilst it's been off the road. I'm very busy and I struggle to find the time to get it back up and running. I've been turning the engine over once every few days and everything seemed fine, until tonight..!

When I tried to unlock the car, the alarm started sounding. The key fob wouldn't work so I had to unlock manually. The alarm would keep going off constantly until the key was in the ignition. Then there was the disappointing realisation that the battery appeared completely flat. Turning the key did absolutely nothing - no lights, no sounds. Dead.

So... if some kind soul could answer these questions hopefully I'll be more clued up by the end of the night;

1) The battery was changed 7 weeks ago. Given that I've only been turning the engine over briefly once every few days, is this a reasonable time-frame for a battery to become dead (especially given the freezing weather lately)?
(The car has been off the road for over three months due to a puncture and other reasons - so it's not been driven at all in all that time)
2) Is the alarm sounding as a result of the dead battery? It's probably been pissing my neighbours right off tonight :headbang:
3) Should I definitely invest in a trickle charger to stop all this hassle!? :rofl: (If so, any recommendations?)

Thanks guys. Love you all :P
 
Hi Matt - I don't know you well enough to love you, but I have some answers / theories...

1. No, not reasonable. But if you have just been starting it then switching it off after a minute or two then I reckon you are using a LOT more power than the engine has time to put back in. That could do the battery in combined with cold weather I guess.

2. If the alarm keeps going off on it's own then that could be your problem rather than the battery - I left my window open slightly when I left my car at the airport once. It was windy and the alarm must've kept going off as when I got back the battery was dead, and that was the only explanation. Took 24hrs to kill it. Perhaps have a garage look at the alarm ? Or check the bonnet sensor as they do fail, and IIRC one of the things that happens is that the alarm goes off randomly / a lot.

3. If you're not driving it much... Yes, I think that might be wise. Damn sight cheaper than buying a battery every 7 weeks :lol:
 
2 things i would do first Matt , ,
1) disconnect the bonnet sensor
2) trickle charge the battery for 24/48 hours

That should show if the bonnet sensor is a culprit , sometimes having had the bonnet open it doesn't close onto the sensor correctly , they are sensitive & once they play up then can be a pita

Once battery is fully loaded try reconnecting bonnet sensor to see if it was low voltage or indeed the sensor

your love is noted :thumbsup:
 
CTEK battery maintainers are forum favourites. As bing said Turing the car over is going to use up more juice than it generates. Also not good for the engine, best to leave altogether.
 
I would answer Yes to 1). I think that's more than enough to drain a new battery.
 
Maybe try not arming the car - if that's an option? Use the key to lock it..and see how it goes..

..and get your alarm fixed ;-)
 
Could well be the alarm sensor on the bonnet. £11.00 rip off for a tiny piece of plastic from the dealer. That's perhaps why the alarm keeps going off.

I'd say it could well be enough to drain the battery. Ours has been sat for a week lately and we've come to use it and it's flat...

Now on trickle charge in the garage using a CTEK and it's been great. Started it on Sunday after 3 weeks and it started no problems and with none of the strange dial resets or the nav re-setting itself.

Worth the investment to keep it topped up and the battery in good condition.
 
Good morning everyone,

Thank you so much for all your replies :D

Just to clarify - because perhaps I didn't make it very clear in my original post - the alarm was only sounding last night. It never goes off normally. I read that a low/dead battery could cause the alarm to sound when unlocking the car?

SamUK said:
Maybe try not arming the car - if that's an option? Use the key to lock it..and see how it goes..
Click to expand...
So if I unlock/lock the car by turning the key it will eliminate the possibility of the alarm sounding again?

srhutch said:
CTEK battery maintainers are forum favourites. As bing said Turing the car over is going to use up more juice than it generates. Also not good for the engine, best to leave altogether.
Click to expand...
I have just done a t'internet search for CTEK chargers and multiple models came up. Is there an optimal model for a 2.5l Z4?

I'll be definitely getting it sorted this weekend. I'll get it on charge, book in my mobile tyre fitters, get it taxed(!) then get it off transport mode. Oh and then look at fixing the motor for the roof :roll: I might even clean the bloody thing :thumbsup:
 
Stratts said:
I would answer Yes to 1). I think that's more than enough to drain a new battery.
Click to expand...

I absolutely agree. To turn an engine over and start takes a lot of battery power. If you are regularly starting the engine, letting it run a minute or two, then turning off, you are draining the battery. Also remember, this cold weather is harder on batteries and is the time when many old batteries just give up and die (I appreciate yours is new)

This is also the worse thing you can do to your engine. The wear on the engine parts is much greater until properly and fully warmed up. if you have a CTek, or similar, keeping the battery healthy, the car can be left for weeks without starting, not as good in my view as just using it regularly but ok. if you do start the engine, the car should be given a good 20 -30 minute drive, not just left idling until warmed up.
 
Any of the ctek units will be sufficient however in down the line you may upgrade to an AGM battery, the MXS 5.0 would probably be your best bet.
 
Thanks guys,

@Midhurstman - Yep in hindsight I should have realised I was doing more harm than good. Lesson learnt!

@NeilP - Thanks, I'll look into the MXS 5.0 then. Hopefully I can get one delivered before the weekend. Btw, that's a great looking Zed you have there - awesome number plate too! :thumbsup:
 
I've now got a ctek on order but I've just had a thought... Does it connect to the actual battery in the boot or does it use the contact points under the bonnet?

The reason I ask is that my car is reversed on the driveway so the boot is closest to the house.
 
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