battery light - alternator, or something else?

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 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

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

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.

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.

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.