Aalternator failure - what should be the charging voltage and current

szczota81

szczota81

Messages
103
Location
Gdynia, Poland
Vehicle
T5 SE 140 4Motion
A loose wire from the fuel high pressure pump caused a fuel leak that damaged the alternator, which stopped charging. The car was taken to a service center where the alternator was repaired.

After this repair the camper unit shows that the voltage is 13.9-14.0V and 2A or less charge. Sometimes even zero A. However, after a short drive, the car at a neutral gear starts to raise the RPM from about 800 to 1000, probably to increase the voltage or charging current.

Therefore, a second alternator was inserted and unfortunately the situation is the same.

From what I remember before the failure the caper unit was showing a higher current (amp) while driving, around 4-5A.

I have two questions:
1) Can you tell me what voltage and amp values are shown in your cars?
2) Does anyone know what could be causing this behavior of the car? Especially low charging current?
 
It is normal for the alternator not to charge once the battery is fully charged (Bluemotion).
Turn on lights and blower and see if it kicks in.
If you unplug the battery monitor, it may start charging as it will not know the state of charge.
 
My car is w/o Bluemotion.
Can you tell me what is a voltage on your camer unit during driving?
 
I just saw you have a T5 (didn’t see earlier as I was on my mobile)

you should have 13.8 to 14.4v
 
Do you know what can be a reason for lower voltage? In moste cases I have 13.7 during driving.
 
Can someone recorde the screen of camper unit from the car (with information abut voltage). I need movie when engine is off and half a minute after engine starts.
I would like to compare the values.
 
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