Battery, Alternator, other, don't know?

[Electric Leyland]

Just going back to that Audi I got last weekend, the garage owner said he had been driving it around for weeks and it had never caused a problem, started first time every time on the button, which I believe. I think he had only been doing short drives in it, in Cornwall, which the previosu elderly and now deceased keeper had also been doing. It had also been SORNed for a few months prior to the current month's activities. Symptoms:The first 75-100 miles of the journey back were fine. The first problem encountered was it wouldnt start after a service station pit stop, battery was dying. After 10 mins of leaving it and then trying again, it just managed to get going. I thought it may have been because I was testing out the lights after switching off the engine.30 or so miles later, towards the end of which I noticed the indicators had stopped working, when we came to a halt at the next services the power had all but died before I even came to a stop in the car park, everything gone.Bought jump leads, car now fine after a jump start. OK for another good 30-40 miles before repeating the electrics dying process again.Repeat to fade all the way back, a good 5 stops in all. The question:Will a new battery sort the problem out, or am I wasting my time as it ia more likely to be the alternator that's the problem?

[wuvvum]

I had an almost identical problem with my first Dodge 50 recovery truck. It was raining when I drove it home, and the wipers gradually got slower and slower and then stopped completely. The battery light hadn't come on though, which was odd - the light was working fine as it came on when I removed the fanbelt, so obviously the alternator was putting out some charge but not enough to keep up. I know it wasn't the battery as I bought a brand new 120AH truck battery for it and it still did the same thing (although it took slightly longer to drain than the Astra battery that the pikey I bought it from had put on it ). Also, the fact that your battery is charging up when jump leads are attached suggests that it's probably OK - if it were dead it wouldn't do that.

[Mr_Bo11ox]

I'm not sure if it is the battery or the alternator, maybe its something else altogether. If the alternator was dead, the battery would drain out, then when you put your jump leads on, it would fire up again, then as soon as you disconnected the jump leads it would surely die (dead alternator and empty battery = no electricity at all).If the battery was goosed but the alternator was working, once you had it started you ought to be able to drive all day no problem.Lasting 40 miles off a jump-start is very bizarre. I would probably start by checking battery + engine earth cables and the like, maybe these are heating up with use and getting more and more resistive. At least I would eliminate these from my enquiries before forking out on a new battery/alternator.

[Electric Leyland]

  Mr_Bo11ox said:

Lasting 40 miles off a jump-start is very bizarre. I would probably start by checking battery + engine earth cables and the like, maybe these are heating up with use and getting more and more resistive. At least I would eliminate these from my enquiries before forking out on a new battery/alternator.

I should maybe have added, the 40 miles or so was non stop motorway driving - I know the problem was returning when suddenly my indicators stopped working. The car can still drive on forever if it wasnt for the fact that it was getting dark and some of the motorway journey was unlit with any motorway lights, hence regalar stopping to recharge. Terrifying in fact once its pitch black and you have zero lights, trying to follow H Sceptre in a new Saab leading the way in front.One more thing - once the jump leads had fully charged the battery again each time, seeimingly so seeing as the full lights, beam, dash light, everything fine, the red battery light still remianed on and bright. Then say 30 miels later the electrics would gradually die, and the red battery light would gradually dim along with the rest of the dash lighting, until all electrical power loss, but car performance still relatively ok. Make any difference?

[Mr_Bo11ox]

Hmm, well maybe the alternator is just putting out a token current, enough to keep the ignition system working, but not enough to power the lights then. Try disconnecting the battery with the engine running, if the engine keeps running the alternator must be putting out some current. Then start putting on lights, HRW, wipers, heater blower and so on. If the alternator is not putting out enough juice, this demand will be too much and the engine will die. if that happens the alternator is 100% guilty.

[MrRegieRitmo]

Are you a member of the AA or someone? When my Renault wouldn't start they came out & used one of their voltmeters which he tested on each component, it didn't take long to see that the alternator was not churning out what it should be! I think that was the 2nd power problem I had, because I'm sure the first time I had problems, the battery was replaced so I knew unless the battery was duff it couldn't be the battery again. They also changed one of my terminal connectors because the old fashioned tap style tightener was no longer firm, infact it literally just spun round and charge was seeping from it as a result of the connector not being tight to the battery, so off they both came & on went a couple of snug clean metal connectors!

[Electric Leyland]

Thanks all, this is invaluable assistance. Yeah i joined the AA Relay a few days ago should I encounter total shut down on the way down south after the RR show Sunday eve / Monday am, as H Sceptre won't be around with the pace car. Its a last resort should it go all thrups up. Cant see myself getting a new alternator sorted prior to attempting this trip. I wonder if a new battery would tie me over for that journey, or would I just knacker that if its deffo the alternator?

[marinast]

I had a simular problem on my 214 last year. The battery and alternator were fine, but one of the battery leads had broke inside.

[bigstraight6]

Hmm, had a similar problem on 'the wreck' ('64 Zodiac) and went down to my friendly local breakers yard and got another battery for a tenner and all has been well for over 12 months

[Dead_E23]

I have a feeling that it might be the diode pack on the back of the alternator, but possibly worn out brushes. A cheapo multimeter from the local pound shop would probably help diagnose the problem - you'll be able to see what the alternator's putting out and check if there's a voltage drop between alternator and battery to eliminate dud wiring and so on. If you've got any Haynes manuals lying about istr they've got quite a good section on what to check - doesn't matter which model it's for, as long as it's something with an alternator.