Alternator Failure

[A55]

Alternator failed on my MR2 mk3, first got the ABS and battery light come on then the ABS light went off after a few minutes.

Going to book the car into the garage tomorrow, while I was hoping to go to the lakes on Wednesday I know I can't do that now but am I OK to use it locally?

[Richard-D]

Do you know why it has failed? On some engines the aux drive belt drives the alternator and water pump. If the belt was the cause you wouldn't want to drive those vehicles. Can you charge the battery?

[E-bmw]

How do you know it has failed?

[A55]

Thanks!

It is not over heating.

Borrowed a gizmo that you clip on the battery and it reads out the charge of the alternator which is zero.

I can charge the battery!

[E-bmw]

A55 said:

Borrowed a gizmo that you clip on the battery and it reads out the charge of the alternator which is zero.

I can charge the battery!

Was the alternator supposed to be charging at the time, smart alternators aren't always charging?

What was the battery voltage at the time before you started the engine?

What car is it?

[Richard-D]

In that case if you fully charge a good battery (and alternator failure really is the only problem) you will probably get away with 30 minutes of running between charges. To be certain you would need to measure the capacity of the battery and the current draw of the car when running. Obviously makes sense to turn off every electrical load you can. Not a good idea in anything other than an emergency of course.

[Peanut Gallery]

I have broken a fan belt completely on a Wednesday on the way to work, drove a fair few miles, including night time drives through to Sunday when I noticed bits of fanbelt in the engine bay.

Air cooled engine, no power steering, no issues, the hardest bit was to try clean up bits of exploded belt from everywhere. I just stuck a new belt on and carried on driving, did not charge the battery.

[Dan_The_Man]

Yes charge the battery and use it with everything switched off to save battery power.
Once blew an alternator south of Paris, managed to charge the battery overnight on a campsite and get all the way back to Guildford via the ferry on one charge. Voltage regulators are about £25 if you fancied repairing the alternator rather than a new one.....

[A55]

Thanks for advice

Dan_The_Man said:

Yes charge the battery and use it with everything switched off to save battery power.
Once blew an alternator south of Paris, managed to charge the battery overnight on a campsite and get all the way back to Guildford via the ferry on one charge. Voltage regulators are about £25 if you fancied repairing the alternator rather than a new one.....

Voltage regulator, how does that work?

Need to take it in for repair, was going to do it last week but never got round to it.