Battery Light Comes On During Acceleration

[mostwired]

My battery warning light comes on for a split second when I start accelerating in first gear. It only happens in the first, and only when I accelerate moderate/hard. Is there a high load on a battery during acceleration in first gear for some reason? (maybe, my alternator doesn't provide enough current for a moment?)

I replaced regulator and brushes a year ago - so should be like new. Alternator also cranks out healthy voltage when I checked it, even with all other equipment draining it (heater, radio, lights). All fuses are fine. What could it be?

[Furious]

hmmm, could be the alternator again, it could be overcharging. but its sooo hard to tell without a proper diagnosis, it could be just a loose wire also , who knows, do you have any fault codes?

[docrobot]

Just a guess, but your belt may be slipping.

Only in First, where the acceleration is the highest points to the belt - maybe...

[mostwired]

No fault codes at all. I didn't think about possibility of overcharging... might be possible - especially that the A/C is automatically disabled for the period of hard acceleration - just the fan blows air. I have replaced the belt about a year ago and checked the tension again. Strange thing is that the battery light seems to stay on longer than before - two months ago I could barely notice something blink - no it became more pronounced.

[aheath]

Man, think cheap fix first when approaching ANY problems.


I thought I had to replace my thermostat in my old car, turned out I just needed a new radiator cap. An expensive job or tedious job turned into a cheap one.



Check the belts!!

[NeverLeaned]

First guess would be the belt is slipping..... (which would mean the tensioner is probably shot)

Give it the hand test.... with the car off, push down on the belt with your hand. The belt should have a bit of play, but not more then an inch or so.


You can also Grab a bar of soap and hold it on the pulley side of the belt why the car is running.... the soap usually a quick fix to belt problems on the older cars that use pulley tensioners... but it could help you diagnose whether its a tensioner or something else.

[victorgallas]

It could be a failing belt tensioner, im sure uve replaced the belt, but what about the tensioner arm itself?

Also, if not the alternator, check for corroded, loose wires. On back of alternator and battery.
And if battery is old, it wont hold charge any more, since it gets to a point of saturation, this is for real..

Anyway, if you replaced brushes and coltage regulator less than a year ago with BMW original parts, my guess is that you have some dirty, corroded wires somewhere.

If you used aftermarket parts, let me warn you, they are cheap, but they break way sooooooner too.

So put the voltmeter with the car idling, you should get something close to 14v, not above, high 13 to tops 14 volts. But even if you get a voltage reading, that wont indicate amperage flow. This means that if you have a loose, dirty, corroded wire, you will get some energy flow, therefore the voltage reading, but not all the flow, meaning, not all the amps, so you have a problem on the charging system..

Check that,. im pretty sure is something dumm..

let us know

[NeverLeaned]

13.8 - 14.3V actually

[victorgallas]

Originally posted by NeverLeaned@Apr 6 2005, 10:13 AM
13.8 - 14.3V actually

[snapback]326583[/snapback]

Yes those are the correct values, i did not have the manual on my hand,
thnaks ..