Altinator Only giving 13 VOLTS

citroenxm · Post by **citroenxm** » 20 May 2011, 18:54

Hi All

Ive got a concern, Ive got a car, Petrol injection, however, the altinator is only giving out 13 to 13.1 volts out through the whole rev range..

The Battery light shows then when started goes out completely.

Ive got a bit of a journey to do, will I be safe, or not?

What sign is it giving tell me Ive only got 13v - Or is the altinator totaly buggered already?

Thanks
Paul

mongoose100 · Post by **mongoose100** » 20 May 2011, 23:15

13.1 is a fully charged battery. 13.8 and above should be what you're aiming for when the alternator is charging correctly.

The brushes may be worn or stuck, try tapping alternator with something solid - this sometimes helps if the brushes have stuck

dnsey · Post by **dnsey** » 21 May 2011, 08:20

As the warning light extinguishes, it's more likely that the regulator is faulty. In many alternators, regulators are easily and cheaply replaceable.

HDI · Post by **HDI** » 21 May 2011, 09:42

Brushes or regulator. Both can be replaced easily and cheaply but the alternator will have to come off to do it.

BX · Post by BX » 21 May 2011, 14:54

Beware of jumping to conclusions. If the battery / no-charge light goes out as soon as the car is started there is a good possibility that the alternator is ok. What you need is an ammeter along with the voltmeter. If the alternator is pumping several amps into the battery but the battery voltage is not rising to over 14V there is a good chance that it is the battery that is on the way out. It may be starting ok now but some day soon!!!. Either check the charging current as well as the voltage or swap out the battery with a known good one before spending money on an alternator.

imperial21 · Post by **imperial21** » 21 May 2011, 18:32

I would say alternator or even check the belt & tensioner, I would be very careful how you go as your car has fuel injection it has a electric fuel pump which would eat the battery charge up quickly !!

Post by **CitroJim** » 21 May 2011, 18:55

BX wrote:Beware of jumping to conclusions.

This is the gospel... Mr. BX, an absolutely excellent set of points very well made

Is this the car I think it is Paul? If so, the electronics on it will suck a battery dry before you're even over the Menai bridge...

wheeler · Post by **wheeler** » 21 May 2011, 19:01

Are you checking this at the battery terminals or direct on the output of the alternator & its casing. there is always the possibility of voltage drop through the positive cable or engine earth leads.