I have a funny problem which I noticed recently. When I start the engine on my Def 110 200tdi the Amp meter shows negative and as the engine is run or the throttle pressed it starts showing about 10% positive from the centre line.

The minute I put the parking lights on the amp meter shows about 5% negative from the centre line and it goes to nearly 25% negative from the centre line when the main head lights are switched On.

Is there any issue or there is a problem in the charging of the alternator. We even checked with a meter connected to the battery and it show everything is ok.

Any advise from you experts will help.

When you have your parking lights on is the engine stopped? If so, then that is normal as it is indication that your battery is discharging.

When you turn on your headlights with the engine running the amount of amps is greater, and the meter is showing how much power the alternator is kicking out to charge your battery and run your lights.

If you connect a volt meter to the battery, you should find a charge of between 13.8V and 14.4V across the terminals, which shows that everything is OK.

Hope this helps.

Oldseadog said:

When you have your parking lights on is the engine stopped? If so, then that is normal as it is indication that your battery is discharging.

When you turn on your headlights with the engine running the amount of amps is greater, and the meter is showing how much power the alternator is kicking out to charge your battery and run your lights.

If you connect a volt meter to the battery, you should find a charge of between 13.8V and 14.4V across the terminals, which shows that everything is OK.

Hope this helps.

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When the parking lights are ON the engine is ON too. Yes it is normal as the battery is discharging. Will check tomorrow and see if I get the voltage that you have mentioned while the engine in ON and the headlights are On too. Thanks a ton mate.