charging system

Post by **autojohn** » 09 Apr 2006 08:37 pm

My 340 DL volvo is indicating on the dashboard the battery sign in red.
The car starts ok, but then again it will if the light has only this day just come on. I seem to remember that I could check if the alternator is working if I connect a multi meter to the battery then rev the engine, if the voltage goes up from 12 + to 14.5, then it indicates the alternator is ok. So with this `doubtfull` knowledge I did just that but the voltage at the battery didn't alter at all. The battery is only about 9 months old, the drive belt is ok. If the alternator is suspected how would I test it with a multi meter?
So if anyone could please help to direct me in the right direction I would be very grateful indeed.
Regards. John

Post by **pettaw** » 09 Apr 2006 08:42 pm

I think you just did the main check. If there's no charging voltage then you're alternator isn't putting anything out.

Before you condemn the alternator itself just make sure all the connections to it are OK, even the little wires going to it, cos alternators need a voltage across the coil before they generate any power.

If you've not done anything to the car recently and the wires all look correct and properly fastened then you'll almost certainly need a new alternator.

Post by **autojohn** » 09 Apr 2006 08:51 pm

pettaw wrote:I think you just did the main check. If there's no charging voltage then you're alternator isn't putting anything out.

Before you condemn the alternator itself just make sure all the connections to it are OK, even the little wires going to it, cos alternators need a voltage across the coil before they generate any power.

If you've not done anything to the car recently and the wires all look correct and properly fastened then you'll almost certainly need a new alternator.

The only thing I've done is about a week ago, I left my lights on when parked for a few hours and the battery was flattened completely. I was surorised at this because my battery was almost new. I put the battery charger on whilst the battery was still in the car, for two hours. All was fine after that, untill this latest problem occured. I'm now wondering if I damaged the alternator in some way by charging the battery in car without disconecting the + cable. What do you think Pete?

Post by **autojohn** » 10 Apr 2006 12:44 pm

Hi guys, the problem has been solved, but not before I got another one from the car breaker for £15.00.
I was taking my old one off the car and discovered the thick red cable from the alternator was broken inside its insulation. But hey, I now have a spare that I can get re-furbished, and added knowledge to my memory bank )

Post by MJ » 10 Apr 2006 03:33 pm

Good positive thinking there

Post by **foggyjames** » 10 Apr 2006 07:09 pm

And 1/3 of a tank of fuel isn't the end of the world anyway

cheers

James