battery issues.

[ben g]

i thought i had already made a post about this, but i can't find it at all.

anyway, when i first test drove my Z4, the red battery light was on, on the instrument cluster. 2 days later when i picked it up it had gone, and didn't re-appear until winter time.

last summer, a couple of times i left my radio on for a while and it drained the battery. i must have done the same thing a couple weeks back and needed a jump start again. it should've been able to handle it though as it wasn't on for longer than 15 minutes max.

my question is, does this picture of the inspection hole on the battery mean the battery is fine (albeit old, date on it shows april 2008) and it's the alternator at fault?

 

[gallaghb]

Battery light on in my experience anyway has always led to alternator being at fault.

That said don't know what the light on batt means, someone will be along to clarify I am sure.

 

[fixit man]

i thought i had already made a post about this, but i can't find it at all.

anyway, when i first test drove my Z4, the red battery light was on, on the instrument cluster. 2 days later when i picked it up it had gone, and didn't re-appear until winter time.

last summer, a couple of times i left my radio on for a while and it drained the battery. i must have done the same thing a couple weeks back and needed a jump start again. it should've been able to handle it though as it wasn't on for longer than 15 minutes max.

my question is, does this picture of the inspection hole on the battery mean the battery is fine (albeit old, date on it shows april 2008) and it's the alternator at fault?

Battery light on when engine is running ..means not charging generally, unless there's a wiring fault..unlikely !

Can't really see the battery indicator...but that just tells you the state of charge of the battery, doesn't say If it's performing to it full capacity..cells could be damaged etc., but could still be fully charged.

There are ways to test it , and the charging system , but you'll need the tools.

 

[ben g]

a few guys in work said the same about the battery light being on, but i'm just curious as to how it's managed to power up my car every day without fail. surely if it's buggered, then it wouldn't charge the battery at all?

 

[fixit man]

a few guys in work said the same about the battery light being on, but i'm just curious as to how it's managed to power up my car every day without fail. surely if it's buggered, then it wouldn't charge the battery at all?

It might be charging a small amount and depending on your usage headlights etc., somedays it will not be enough !

Is your battery light on Now ?

 

[cj10jeeper]

99% it's just a tired old battery. feels it from time to time. Rarely do alternators fail and if they do, you'll get the light on most of the time and soon be failing to start, bim headlights, etc.

Best way to test is just stick a meter on and see the voltage with and without engine running.
Good battery will be 12.4v standing and around 14.x running

 

[ben g]

a few guys in work said the same about the battery light being on, but i'm just curious as to how it's managed to power up my car every day without fail. surely if it's buggered, then it wouldn't charge the battery at all?

It might be charging a small amount and depending on your usage headlights etc., somedays it will not be enough !

Is your battery light on Now ?

no, hasn't came on for about a week or so. only happens when the car hasn't been driven for hours. from a warm start the light never comes on.

 

[srhutch]

As cj says sound like battery. Once you start having problems with them its time to replace.

 

[ben g]

cheers. best off replacing with a bosch one?

 

[Toe-side]

"i thought i had already made a post about this, but i can't find it at all."

http://www.z4-forum.com/forum/viewtopic.php?f=3&t=49799&p=722954#p722954 You Did!

Its a great thing the search facility