(G) Uno TD : Batterie warrning when over 4000 rpm

Since few days I have a strange phenomenon on my Uno TD :
When the motor is up 4000 rpm, the batterie warning light up.
At 4000 rpm the light is almost invisible.
At 5000 rpm the light is fully lighted up.

Can somebody tell me what could happen ?

Strange at all! A voltmeter will be helpful. Try to proceed to following measurements. While engine speed kept at about 1,500 rpm, check voltage at the generator terminals, and at the battery posts. There should not be noticeable difference between readings. In case of different readings, further checking is needed to search for poor connection. But the main cause of the failure you exposed may be due to worn brushes (remedy: replace worn brushes), stuck brushes (remedy: clean them). However, I think that the copper collector rings of the rotor are badly out of centre worn, causing brush bouncing at high revs and finally the warning light on. Try to check (rapidly, too;)the voltage when warning light is on. If voltage decreases, this may be the case. If rings are not too worn, these may be machined on a lathe, otherwise the safest plan is to replace the alternator by another one

Hi,
I would check the regulator part of the alterntor, this is a small removeable part. Try replacing this first as this can causes the symptoms you described.

Cheers

Matt Endean