Help! Have I killed my car?!

G

Gebbly

Member
 Hersham, Surrey
This weekend I've been trying to install an aftermarket android stereo head unit in my Z4M. I removed the original unit connected in the new and spent some time getting the stereo and gps working.
I have just tried turning on the ignition, the engine doesnt turn over at all there is a loud click click click until I release the key, the ABS light on the console is rapidly blinking and the light on the sport button down near the gear stick rapidly blinks until I turn the ignition key to the fully off button.
If I try and start the engine and get the clicking, release the key back to position 2? the key cant physically turn again to engine ignition unless I turn the key to fully off and start again. The windows moved partially down and would only go up if I raised the passenger window a bit then the drivers side then the passenger and then the drivers side.

I thought perhaps the aftermarket stereo was interferring with the electronics in some way and so have removed it and reconnected the original head unit but the same problem is still occuring.

It occured to me that I did not disconnect the negative of the car battery whilst I was doing this so just in case I disconnected then reconnected the battery after 10 seconds in case that achieved any sort of reset but no luck.

I am now rather panicked that I have a dead car on the driveway. Can anyone offer any advice please?
 
Never done this before but do have jump leads. I connect live to live and ground to ground on the 2 batteries? If its dead I wonder if the new stereo drained battery overnight whilst it was connected. Hope not as the key wasnt in the car.
 
Oh my god thank you so much! I was having a major panic. Hooked the jump leads up to our other car, gave it a minute and Emily (my Z4M) immediately turned over and is alive again. Guess I've learnt how to jump start a car now.

Once a car battery has gone flat like this is it as good as new once fired up and driven around or is it a sign that the battery should be replaced with a new one?
 
Gebbly said:
Oh my god thank you so much! I was having a major panic. Hooked the jump leads up to our other car, gave it a minute and Emily (my Z4M) immediately turned over and is alive again. Guess I've learnt how to jump start a car now.

Once a car battery has gone flat like this is it as good as new once fired up and driven around or is it a sign that the battery should be replaced with a new one?
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Once charged up again it should be ok and at the same level as it was before your installations. Each battery has it’s lifespan and when they get old the tend to get flat easier. There’s one exception, though: If a regular car battery gets flat in subzero temperatures and the cells freeze, it’s often kills the battery.
 
I dont know how old the battery is and I have only had the car this year. So i might just replace the battery so I know its age.

I'm trying to find from the forum what a suitable battery is for the Z4M. I can see people say it should be an AGM battery and that the CCA is important but I cant find details of what the numbers should be for the Z4M. I can also see people suggesting Bosch.

Would this be suitable for the Z4M?
 
Don't need AGM, it won't hurt it but unnecessary.

Varta Silver E44 is same size as OE I believe. Been running for years with no issues.

Take the battery out it's probably got a production date on it, if it's fairly recent just charge it up and go, no need to waste money on a battery if you don't need to :thumbsup:
 
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Good to know it was just a flat battery!

If you need one I bought an Exide 096 AGM battery for my Z4 in April 2021 for £105 delivered from Tayna. They are usually very competitive on price and have all brands, Bosch, Exide, Yuasa, Varta, etc.
 
Gebbly said:
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If I try and start the engine and get the clicking, release the key back to position 2? the key cant physically turn again to engine ignition unless I turn the key to fully off and start again. ...
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This is normal BMW behaviour, nothing wrong here.
 
My z4 has something that drains the battery. I think there is probably a tracker hiding somewhere that has died. I have had a couple of occasions when it was so flat I had to connect the jump battery in order to get tye smart charger to even see it and start charging. It has charged OK both times after that so yours may also do that.

If you don't drive it much and have it indoors then trickle charge or a smart charger always connected is a good idea.
 
Thanks for the helpful info all. The engine started first time when I turned the key last night so I think the battery has life still in it. However, its an easy part to replace so I have a new Varta battery on its way just so I know thats a new component.

I was a bit concerned about something draining the battery when the car is parked up and I did notice that the new android head unit has wifi. I had connected it to the house wifi to install a navigation app (magic earth in case anyone is interested). What I realised was it was automatically connecting when it sensed it was within range of a "known" wifi network. For that "sensing" to work it would have to be constantly polling to see if it could spot these known wifi networks so perhaps that was draining the battery. I have found the setting to switch the wifi on and off and told it to only connect to wifi when I explicitly turn it on so that should stop the wifi polling and hopefully help.
 
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