Well my 91 V8 hasn't been driven in weeks. I took her out a few days ago, blinkidash and all. Coming to a traffic light to slow down I've hit the brakes and the dash cluster starts to dim (no warnings either due to blinkidash... I really should replace them damn capacitors), turn on my blinker and they stop working and the dash is virtually blinking at me, EMV cuts out and no power steering. Somehow I ended up babying the car back home (only down the road) and she completely calls it quits in the driveway of my apartment (much fun that was).
So straight away I'm thinking the alternator has packed it in. I've had a look and it does't look like it's in tip top shape, rather looks like as it's been for the past four or so years of ownership.
I jumped the car and left the car running (cables off) to see if I could recreate any symptoms of a bad alternator but with of course with my luck she idled like nothing happened up until warm. Tried starting the car a couple of minutes after and whilst a little slow to kick over she did and again idled with no problems what so ever (about 10 minutes at a time, both times). I've turned on everything on to put a higher load on the battery and the headlamps dimmed in time with the hazards flashing. Next day I try starting her again and dead battery.
In the end I think it's the battery causing all of this as opposed to the alternator, but what would've caused the car to lose all power while driving? All terminals seem to be fine (I removed, cleaned and reinstalled), no blown fuses.
The battery is only around 18 months old as well (Century NSZ70XL from memory... never had a problem with the brand either and of used it on about 3 or 4 cars).
Sunday, September 01, 2013 - 11:26 pm, by: David Hall(Dr1zzle)
It certainly sounds like its an issue with the battery. But my guess would be the alt. is not putting out enough charge.
Put the battery on a trickle charge for around 10-12hrs (over night). Do you have access to a multimetre? If so, check the voltage of the battery. It should be around 13.1v once fully charged. Chuck the battery back in, and see what charge you are getting to the battery when the engine is running.
With a full load, a healthy alt. should be putting 13+ volts into the battery. If it is not, which I think may be the case, then it is your alt. at fault.
Monday, September 02, 2013 - 12:27 am, by: Robert Day(Lexsmaz)
Sounds like the Alternator is intermittently charging & the last time it wasn't charging for quite a while it flattened your battery & hence everything fell over ..
In theory once the car is running the car should be able to run without the Battery so long as the alternator is good, not a good thing to try on modern electronic cars though ..
Monday, September 02, 2013 - 05:52 am, by: Matthew Sharpe(Madmatt)
A bad battery can definitely cause loss of all power while driving, at least when the revs drop off but power demand is still high (eg heater running, headlights on, wipers going etc) - the electrical can, for brief periods rely on the battery to supply the difference between what the alternator is producing at low revs and what the electrics are demanding - so yes, test the battery (or get it tested, most auto electricians will probably do it for free)
Wednesday, September 04, 2013 - 10:39 pm, by: Myles Jantzen(Maxx999)
Agree with what Matthew has said, happened to me before when left a car sitting for while, was ok driving until started raining and had to use headlight's and A/C to demist windows, sitting at lights and dash would dim along with headlights, then brighten up when started driving before finally giving up when stopped to check. New battery and all good.
Battery voltage could have dropped too low and damaged battery, next time might want to disconnect it or try using trickle charger.
Wednesday, September 18, 2013 - 06:02 am, by: Glen Mills(Millsyg)
I had the same problem minus the blinking dash after replacing my alternator. Turned out my new alternator had a faulty regulator. When the regulator got hot, the alternator would stop charging the battery and the car would die slowly as the battery drained.