Battery warning light

sk93

Veteran
 Nottingham
hello friends :)

Over the last, say, 5 days, I've occasionally (like three out of 20 times) started the car up and found the red battery warning light has come and stayed on.

I checked the battery condition indication and it's green.
Also checked it's voltage with ma trusty multimeter and all looks good there.

I'm guessing the next thing is possibly the alternator?
However, I know it is working, as I have drained the battery a few times and had to jump start it.. but after the jump the car starts fine without fault each and every time (doesn't even struggle).

any ideas before this becomes I problem I really care about? :(
 
Test the voltage acroos the battery with the car running - should be between 13 and 14 plus volts if the alternator is working OK - if less then possibly a duff alternator.
 
I would not worry about it unduly as the Z4 battery warning light once on will stay on for the entire journey or at least a long while, resetting next time you start the car. The recent weather will have put a huge strain on the battery spinning a very cold engine, while itself down on output due to temperature.

I suggest put it on a proper maintenance charger.

I'd be more concerned that yo drained the battery a few times for 2 reasons 1) why - what fault is causing you to do this and 2) cycling a battery to flat is the quickest way to destroy it.
 
Mine used to do this at random but everything always checked out with the trusty multimeter. Mentioned it to dealer at a service after all my dashboard lights went out. They didn't apparently do anything but it came back all working and never played up again. Suspect it is just very sensitive if your battery is even a bit discharged.
 
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