battery light stays on

[Golfer_76]

Hey all.
When i start my car and drive it for a while. Then turn it off, leave it and come start it again while its still warm, the battery light on the dash stays on. My alternator is in good condition and I replaced the earth strap that goes between the alternator and motor but it still happens. Any suggestions on what it could be?

[fred27]

Try checking the earths behind your instrument panel. If you or a friend have a multimeter, hook it up to the battery when your engine is running to see if you are getting the correct charge. Also check your regulator.

[gldgti]

Hey all.
When i start my car and drive it for a while. Then turn it off, leave it and come start it again while its still warm, the battery light on the dash stays on. My alternator is in good condition and I replaced the earth strap that goes between the alternator and motor but it still happens. Any suggestions on what it could be?

The charge light doesnt go out unless the alternator outputs a certain threshold voltage. If you start the engine hot (when the idle is lower than when cold) then the alternator might not begin charging until you rev up the engine a little bit.

If the light is staying on even after you rev the engine up a little, you may have a bad connection to the b+ wire at the alternator.

[Golfer_76]

when i first start it. the battery light come on. once i give it a rev it goes off. but once ive been driving the car for a while and the car is hot and i stop for a few minutes to go into a shop etc. and come back to start it the light stays on. the car still starts and runs fine.
which is the b+ wire at the alternator?

[IBN]

I had a similar problem years ago - traced it to a dry joint on a diode on the rectifier bridge. With the temperature cycling in the engine compartment the bad joint would go high resistance and the battery light would stay on. Resoldered all the diodes and it's bean fine for the past 20 years

[Golfer_76]

where about's is the rectifier bridge?
i noticed the other day that one of the connectors onto the back of the alternator wasn't on properly. attached that how it should've been and hoped it was that, but the light kept coming on.

[IBN]

Uh oh. It's been a long time now. If memory serves, you need to pull the alternator apart, as the bridge is inside the alternator, at the non-pulley end of the device. Good luck.

[Golfer_76]

ohh jeez. haha. i pulled it apart not that long ago to replace bearings and just give it a general clean up. thanks for your help mate.