Battery light stays lit too long - at odd times only

[Alias_Knagg]

When I start the engine after a short drive and a short rest my batterylight stays on for 10 to 30 seconds too long. Long enough to give me the warning beeps.
This never happens on cold starts, and not after long drives either it seems.

Anyone else have had this experience?

[berlingo power]

have you checked to see if the alternator belt is slack

[Alias_Knagg]

I'm pretty certain that my charging voltage and battery are good.
http://www.berlingoforum.co.uk/showthread.php?tid=2196
"Alternator/ charging ripple - busted diode?"

At least on idle and light revving standing still.

I'm quite certain as well that my 1,4 petrol multispace from 03 has an automatic belt tentioner.

Why might a belt slip only under those conditions I mentioned?

[Alias_Knagg]

An auto electric shop I talked to earlier, suggested there is a circuit in alternators that backs off the charging voltage when the battery shows a high voltage allready.
I think he called it a compensator, but google can find no such thing relating to alternators.

To the contrary my intuition would be that a short drive would drain the battery more than recharge it..

Perhaps he was only bullshitting about the normal charging regulator. Some "professionals" like to try to keep us mere mortals baffeled about their craft

[brodfather11]

Hi,
Your alternator has to have a votltage regulator, if it did'nt it would boil your battery. It sets the max output to approx 14.4 volts. All alternators make AC. current, Thus the word Alternator, which when passed throught the rectifing circuits Diodes which are built in to the alternator , to DC voltage which is used to charge batteries etc. This can take a lot of effort to turn.(Torque) Your problem may be the drive belt which may be slightly loose which when cold is tight and due to friction heats up quicker than the engine. Ford had this problem on the early 1.8 d escorts, the belts /pulleys on the engine and alternator had three ribs and the belts felt tight but did an awful squealing (think slipping) until after they warmed up. The belts and pulleys were changed to 5 ribs and cured the problem.