Engine: 2.5: battery light - alternator, or something else?

[stinky]

Battery light has come on; do you think I'm missing anything obvious:

Battery shows 11.5V across terminals with engine off.
Battery shows 10V across terminals with engine running - revving.

Battery has a good earth
Alternator seems secure
all belts and cables seem secure.

I reckon it's the alternator (battery is quite new), what do you think?

[capt jack]

I think I'd want to eliminate the battery as the possible cause of the problem. If it's fairly new why not take the car back to the battery supplier and get them to check it anyway? It should cost you nothing, and might help to narrow down the options.

Cheers

Jack

[sonic-1]

the fact that voltage drops when running says alternator prob , most cars push over 12v when reving , if its still fitted with std one whip it of n get yours reconed not service exc as they tend to be fitted with low quality parts !!!!! unless you get a genuine new one ............... but it will cost 4x s as much as a refurb

[Jod T5]

Originally Posted by sonic-1

the fact that voltage drops when running says alternator prob , most cars push over 12v when reving , if its still fitted with std one whip it of n get yours reconed not service exc as they tend to be fitted with low quality parts !!!!! unless you get a genuine new one ............... but it will cost 4x s as much as a refurb

Agreed , alternator issue, you should be getting over 13.5V with the engine running IIRC..
Cheers
Jod

[glock19]

With the engine running, remove the battery terminal (negative side) and see if the engine stalls. If yes, it's alternator. If not, then something else.

[chow]

Originally Posted by glock19

with the engine running, remove the battery terminal (negative side) and see if the engine stalls. If yes, it's alternator. If not, then something else.

do NOT remove the battery leads with the engine running... What planet are you on ????????????? ..as you clearly have no knowledge of the subject id refrain from posting such crap, what are you trying to do totally ruin his engines electrical system?

[DieselDoNicely]

Originally Posted by stinky

Battery light has come on; do you think I'm missing anything obvious:

Battery shows 11.5V across terminals with engine off.
Battery shows 10V across terminals with engine running - revving.

Battery has a good earth
Alternator seems secure
all belts and cables seem secure.

I reckon it's the alternator (battery is quite new), what do you think?

I had my alternator re conned for about £90 about 50,000 miles ago. Same fault low voltage.

DDN

[stinky]

Thanks,
I don't have time to try and fix it myself at the mo, so I've left it with a local independent Volvo specialist. They are going to get it refurbed.
I'll see how it goes.

[sonic-1]

Originally Posted by chow

do NOT remove the battery leads with the engine running... What planet are you on ????????????? ..as you clearly have no knowledge of the subject id refrain from posting such crap, what are you trying to do totally ruin his engines electrical system?

whoa chill !!!!!!!! you do have a point though lifting the concetions off battry while running can cause a spike which could damage the ecu
mmmmmm chow its how yer tell it !!!!!!!!!!!!!!!!!!

[glock19]

I've removed the battery leads before with the engine running to check alternator problems (like I mentioned) and I've even change the whole battery with the engine running (not to loose the radio codes). So from where I stand (on planet earth to be exact). I'm speaking from experience and if you feel uneasy with such procedure, then leave it to the workshops.

Who knows, with your back turned, some might even be replicating what I did.