Battery charging red warning light came on

C

Charly2012

Member
Hi, first post. Greetings to you all. Z4 2003, 2.5 192Hp

Bad news (for me). Started the car yesterday. As always perfect start up, but the red warning light for battery charging stayed on...

The battery has worked flawlessly for 9 years. Not a single problem. Should I assume is an alternator issue? Any hint will be much appreciated.

Thanks and happy new year to you all.

Charly
 
Welcome. Simply change the battery. 4 to 6 years is a real good life, so 9 is way past expectation.

Where in Spain are you from?
 
Thanks for the replies and the welcoming...

I'm from ex-sunny Madrid (a whole foggy week, feels like London :) )

Is there any way to confirm it's a battery issue? Any precaution I should be warned of before going through the process of changing it?

Thanks a lot,

Charly
 
You can stick a voltmeter across the terminals without the engine running. Look for around 12.4v
Less than 12 and it's dead.

Don't waste any time in that age battery.
 
Bit odd that the car tuned over and started well but shows a charging fault light if it's a worn battery? although 9 years is as much as you can expect from a battery.

A charging fault light usually indicates low charge which can be caused by a slipping or broken belt, or worn alternator brushes, or poor earth or cable connections to the battery or alternator. or it indicates overcharging caused by the control pack.

As CJ says try a Voltmeter on the terminals without the engine running looking for about 12.4 ish Volts. and with the engine running to test the alternator where a healthy alternator should be giving around 13.7v at idle and not much over about 14.5v preferably.

Good luck :thumbsup:
 
UPDATE:

Thank you all,

I've just chequed visually the battery. It has the green light so apparently it is fine at this moment. Then I have started the engine. Smooth as always and, to my surprise, no red warning light in the display :idunno: . I have driven for a few miles and everything seems to be fine...for how long, who knows?

I'll do as you say and check voltages. Since I have to fix a few minor scratches next week I'll ask at the garage for more hints.

Thanks again,

Charly
 
Charly - get it fixed soon. Those are classic symptoms of a dead battery despite green light being on. It WILL let you down at the most inconvenient moment...probably a cold damp morning when the battery is given that extra bit of strain.
 
cj10jeeper said:
Charly - get it fixed soon. Those are classic symptoms of a dead battery despite green light being on. It WILL let you down at the most inconvenient moment...probably a cold damp morning when the battery is given that extra bit of strain.
Click to expand...

Agree - leave it and IT WILL LET YOU DOWN :|
 
Same AH as oem and any big label, but just find one with a 4 year warranty such as from Halfords.
Search online too for good prices, although BMW can be competitive at times, but only 1 year warranty.
 
I use a Bosch S6, Alpina has a high Ah rating, but S5 might be OK for you? Got mine from EuroCarParts....


Tapatalking...
 
I have the same problem. The battery shows 11.5 volts and starts the car fine. The charging voltage is 14.5 yet the battery warning light comes on sometimes. It stays off for a while then l start the car and it stays on after driving and then starting the car it stays off. Is it the battery
 
I’m not quite sure why everyone here was diagnosing battery??? Usually, the red light is alternator charging voltage that is low. You need to put a voltmeter on the battery with the engine running. Anything under 13.5V is an alternator issue.
 
ph001 said:
I’m not quite sure why everyone here was diagnosing battery??? Usually, the red light is alternator charging voltage that is low. You need to put a voltmeter on the battery with the engine running. Anything under 13.5V is an alternator issue.
Click to expand...

Exactly right... if it were the battery your car would not start! I had red battery light on my old E46 and it was alternator, the battery was fine!
 
This is a resurrection of a dead thread. Most recent post is observing a good voltage from the alternator, so that's not the fault
The battery is dead if it shows 11.5v and not holding a correct charge and needs replacing immediately. Only caveat is this is assuming the voltage is back to 11.5 a short time after parking and your not talking about left standing for a week or so.
Left overnight it should be at least 12.x, ideally 12.4 - 12.6v on a healthy battery

Although a very low voltage might start a car, pretty soon it won’t and you'll start to get all sorts of electronic errors...
 
Just to add another element for interest, my son had the charge light on on his E46 330D, battery volts 12.6 engine off after charging, running about 12.3. Changed alternator still the same?? Got old alternator checked on test rig and was fine. Much head scratching, then noticed the auxiliary belt did not seem to speed up when rev’d, paint mark on belt confirmed. Turned out the rubber torsional damping element in crankshaft pulley had failed. Not sure whether the Z has a damped pulley, but it’s an interesting story.
 
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