Alternator issue?

[Clarkey]

The other day my +ve battery terminal popped off while driving, drove it for 5-10 minutes until I turned it off and noticed the power had gone.

Anyway, since then it's blown 2 bulbs, a headlight and a dash bulb. It's never blown a bulb at all in the time I've owned it so I checked the voltage to see it wasn't too high. It is pretty high though, 14.5v, regardless of revs without any high load systems turned on. I'm sure it never ran that high before. The manual suggests this is within acceptable range though. What do you guys think though, a bit high, related to the bulbs going?

 

[GeX]

imo that's too high yeah, ~13.8v and would explain bulbs blowing.

regulator on the alternator gone a bit screwy?

 

[Xez]

imo that's too high yeah, ~13.8v and would explain bulbs blowing.

regulator on the alternator gone a bit screwy?

Its high but not that high that it should cause damage... Mine was once chargin at 17v, yes it killed my battery but it didn't blow anything even with dodgy french electrics

If the current was too much i'd expect the fuse to blow first...

 

[markweatherill]

The other day my +ve battery terminal popped off while driving,

1) Turn that boost down.

2) Your alternator may have a 'sense' wire which it uses to detect battery voltage. If that connection is dodgy, it sees the battery voltage as very low and be overcharging to compensate. That's what happened to my Nissan.
If you have a circuit diagram, check the two-pin connection on the alternator, if there is one. One pin probably goes straight to the battery but by a different route to the main charge cable. I fixed it on my car with a wire bypassing the factory 'sense' wire.

3) Or, what happened may have fried something inside the alternator.

 

[Dogbreath]

Having the battery get disconnected from the alternator whilst the engine is running causes something called (amusingly) a "load dump". The alternators regulator has a finite bandwidth, so sudden removal of load will cause a big voltage spike which could be over 80 volts. This is enough to stress any lamps that were illuminated during the event and could cause premature failure. It could also damage the regulator itself.

 

[Jamous]

My guess would be the damage has been done to the lamps and they are starting to fail through useage after the event.

14.5 is high, but not too high, what is the reading with a load on- lights heater etc.

 

[Clarkey]

I think I was just being paranoid, I let it run for a while and it settled to 14.4, unaffected by load or revs, nothing unusual.

At the time the battery came off, I had the sidelights on only so I can understand the dash light going but maybe the headlight going is just a coincidence. It was an uprated type that had been in there for years and in a Subaru for years before that.