Alternator...currently on side of M4 needing a new one

[Bug4029]

Hi all,

Wave if you see me, breakdown truck on it's way and hopefully heading back to central London in the next hour. Alternator has given up on me, anybody that can help with a spare one, it would be much appreciated.

Thanks.

[alan e]

Try unit exchange they repaired my alternator 3 years ago they are in London 168 Ayciffe Road Borehamwood WD64EG 08000528312 or 02089539971 very good service they returned it like new, i think some of the new alternators fit but the charging light stays on something to do with the wiring at the alternator hope this helps and good luck removing and refitting the faulty one its a pig of a job.

[cliff]

Try Wood Auto, they offer a slightly uprated one.

http://www.woodauto.com/zoomImg.aspx?Ref=ALT30391

[lotusflasherman]

Hi all,

Wave if you see me, breakdown truck on it's way and hopefully heading back to central London in the next hour. Alternator has given up on me, anybody that can help with a spare one, it would be much appreciated.

Thanks.

Bit confused why failed alternator required a breakdown truck to get you off the M4. Didn't the battery have enough juice in it to get you home?

[Bug4029]

Hi Phil,

Unfortunately not the battery died on me with 50 miles to go.

Kind regards,
George

[Brit-Car-Nut]

Hi all,

Wave if you see me, breakdown truck on it's way and hopefully heading back to central London in the next hour. Alternator has given up on me, anybody that can help with a spare one, it would be much appreciated.

Thanks.

Bit confused why failed alternator required a breakdown truck to get you off the M4. Didn't the battery have enough juice in it to get you home?

Sometimes, an alternator failure not only stops charging the battery, it starts behaving like a big resistor and quickly drains the battery of the remaining charge.

[lotusflasherman]

Hi Phil,

Unfortunately not the battery died on me with 50 miles to go.

Kind regards,
George

Out of interest ... had you switched everything off that could be and how far did you get on just the battery?

[lotusflasherman]

Hi all,

Wave if you see me, breakdown truck on it's way and hopefully heading back to central London in the next hour. Alternator has given up on me, anybody that can help with a spare one, it would be much appreciated.

Thanks.

Bit confused why failed alternator required a breakdown truck to get you off the M4. Didn't the battery have enough juice in it to get you home?

Sometimes, an alternator failure not only stops charging the battery, it starts behaving like a big resistor and quickly drains the battery of the remaining charge.

Diode failure in the rectifier bridge is relatively rare, it's usually the voltage regulator pack or failure of the carbon brushes. A good battery should run the engine for many miles if everything is switched off that can be, and parking so you can bump-start saves a lot of ampere-hours for running the engine.

Suffered the failure of a Ducellier alternator on a Peugeot Talbot Express based motorhome as we drove off the ferry for a family holiday in France and had a job finding a replacement as all French Peugeot dealers only offered to order one in. Vehicle had an auxiliary battery with Zig charger and mains hookup so for several days we traveled through France running on the vehicle battery first and then swapping across to the auxiliary battery and when that got low we'd park up with a mains hookup for the Zig to recharge both batteries so we could carry on next day. Got to somewhere we liked in the south of France and ordered one and it took 3 days to arrive... very expensive too, compared to Lucas or ACDelco. !

My son had the alternator on his Astra Van fail on a Friday afternoon just as he was about to start a long journey home. He called into a Vauxhall dealer and bought a replacement alternator but was told on the model he'd got the rad' needed to be drained and removed to swap alternators and he hadn't got tools for that so bought another battery to ensure he got home.

[Bug4029]

Hi Phil,

It was Sunday so everywhere was closed I was about 60 miles into 190 mile journey when the battery warning light came on, so stopped and checked all the cables (all good), so carried on (car started easily), then the fuel gauge went to 1/4 so stopped again and filled up (knew it couldn't be that low) this was just before Swindon, then battery (less than 6 months old Optima red top (as good as you can get)) only just started car, reves shot up and stayed at 2000 rpm, shortly after all main gauges bar Speedo died on me but revs came down, then engine started running rough and I gave up about 50 miles out of London (might have tried with my booster but that was in London. I had no extras running on the car after the fuel fill up, but before I was charging the phone. I expect the phone charge and the elivated revs killed it off early.

£100 + VAT to rebuild my unit at Unit Exchange so might do the lightweight uprated version (£70-£80) or if I can get one quickly an original.

Kind regards,
George

[Tuga2112]

Can someone explain to me how a dead battery or broken alternator can stop a running car ? my understanding is that once the car is revving it would continue to work even without electricity, what am i missing here ? is it because the alternator acts like a resistor theres no juice to the ECU and the timings/injection goes wrong.

[alan e]

If the battery is dead ie no power from it and the alternator is faulty and not making any electricity to make the spark plugs spark and the petrol pump pump how can the car keep working

[Tuga2112]

now i feel really silly
makes sense, i forgot the sparks are electrically driven, I forgot the fuel pump is electrically driven as well, unlike the PAS pump.
so the broken alternator acting as a resistor will quickly stop the car, but if the alternator is not acting as a resistor then the car should run fine until the battery dies, which makes me wonder how long would it last for.

[lotusflasherman]

Hi Phil,

It was Sunday so everywhere was closed I was about 60 miles into 190 mile journey when the battery warning light came on, so stopped and checked all the cables (all good), so carried on (car started easily), then the fuel gauge went to 1/4 so stopped again and filled up (knew it couldn't be that low) this was just before Swindon, then battery (less than 6 months old Optima red top (as good as you can get)) only just started car, reves shot up and stayed at 2000 rpm, shortly after all main gauges bar Speedo died on me but revs came down, then engine started running rough and I gave up about 50 miles out of London (might have tried with my booster but that was in London. I had no extras running on the car after the fuel fill up, but before I was charging the phone. I expect the phone charge and the elivated revs killed it off early.

£100 + VAT to rebuild my unit at Unit Exchange so might do the lightweight uprated version (£70-£80) or if I can get one quickly an original.

Kind regards,
George

Thanks for info, that's interesting, sounds like you got about 80 miles on the battery but two 'engine starts' would have taken a lot out of it.

Alternator output is around 14.5V to charge a 12V battery that will sit at about 13 to 13.5V when fully charged and because volts wander around a bit the temperature gauge and fuel gauge, which are voltage sensitive, operate at 10V from a voltage stabilizer. I'd guess that the voltage stabilizer behaved oddly when the incoming volts (from battery) got low and hence gave you a false fuel reading, and then other gauges and ECM behaved oddly when volts got even lower. Phone charger doesn't take much power and good idea to have a working mobile when car is struggling but cranking an engine to start takes around 300amps so that takes a lot out of the battery that won't be put back without a working alternator.

I reckon without the 'engine starts' or with your booster you would have got home, but that's hindsight... and not much use for you now.

[lotusflasherman]

Having said it's usually the voltage regulator pack that fails, and they are quite cheap - usually under £20, I'd be checking that out with a multi-meter before spending a lot of money, but I'm a Consultant Electrical Power Engineer.
I've never had alternator problems so not familiar with what fits the Elan alternator but this looks like it may have the right connector...

www.ebay.co.uk/itm/NEW-ALTERNATOR-REGULATOR-FITS-NIPPON-DENSO-TOYOTA-AND-HONDA-ROUND-PLUG-131459-/151221224091

probably best to get old one off and then search on ebay to check serial number but worth gambling £17 to save paying £120 even if you haven't got a multimeter, or understand 'lektrix'. The brushes for the exciter current in the field winding of an alternator run on smooth collars so don't wear anything like dynamo brushes used to but worth checking while its off as new ones are usually under £10 - change those too and you've just refurbished your alternator.

[GeoffSmith]

A word of warning: Over the years, there have been a few cases of alternator failure shortly after an failed OEM alternator had been reconditioned or replaced with a reconditioned unit. I strongly suspect that this was due a combination of inferior replacement regulator/rectifiers and heat soak (very high temperatures at rest due to the location of the alternator).

[niall]

I think that after starting, the greatest drain on a battery would arise from the application of the brakes which light
relatively high power bulbs.
As a 16 year old I ran a Heinkel bubble car in Edinburgh, a city on a hill.
The dynostart did not charge the battery so I was always running between mains charges.
Driving down one of the long hills always was a challenge due to the need to apply brakes and I often resorted to handbrake slowing
to conserve power. I often had to stop before the foot of the hill and let the battery recover enough to power the ignition and
then bump start before the foot of the hill. Happy days.

[lotusflasherman]

[quote="niall"]I think that after starting, the greatest drain on a battery would arise from the application of the brakes which light
relatively high power bulbs.
As a 16 year old I ran a Heinkel bubble car in Edinburgh, a city on a hill.
The dynostart did not charge the battery so I was always running between mains charges.
Driving down one of the long hills always was a challenge due to the need to apply brakes and I often resorted to handbrake slowing
to conserve power. I often had to stop before the foot of the hill and let the battery recover enough to power the ignition and
then bump start before the foot of the hill. Happy days.[/quote]

but brakes lights are 21 watt so 2x21 = 42w/12v = 3.5 amps only while you are braking so not a lot. It's the starting current that takes such a lot out of the battery.

I'm an Electrical Power Engineer and in the 80's worked at Eastern Electricty HQ and took part in the development trials of the Enfield Electric Car - www.bbc.co.uk/news/magazine-25117784
That used 'milk float' lead acid traction batteries and I lived 15 miles from HQ which was about the limit of it's normal range. Top speed was only high 40's so on country lanes going home I'd try not to brake for corners to maintain momentum as I was conscious of holding people (like me in my usual car) up. In winter it was awful - I couldn't use a windscreen heater (electric) so had to drive with side windows open to stop it steaming/freezing up on the inside, thick coat and gloves needed, and could only get home at night by turning the lights off to climb the slight hill into the village. Was a small car but weighed a ton with all that lead on board and when I hit ice is was like sitting in a curling stone - felt I might have more influence by running ahead sweeping with a broom as steering & braking (cadence or otherwise) had no effect at all. An interesting experience that helped prove they might work as a 'city car' but not suitable for rural use.

[lotusflasherman]

A word of warning: Over the years, there have been a few cases of alternator failure shortly after an failed OEM alternator had been reconditioned or replaced with a reconditioned unit. I strongly suspect that this was due a combination of inferior replacement regulator/rectifiers and heat soak (very high temperatures at rest due to the location of the alternator).

Sounds like you can't trust the reconditioning companies then. I'd put my money on the fact a lot of companies doing reconditioning only replace the failed component and clean it up a bit to make it look nice. They give a short guarantee period and gamble the other bits won't fail in that short period at their cost. At their prices there's enough padding to be able to deal with quite a few claims and still be well in profit..

[alan e]

My recon unit is still working ok after 3 years with no problem the thing about having your faulty unit repaired you know it will fit when you get it back

[dapinky]

Sounds like you can't trust the reconditioning companies then. I'd put my money on the fact a lot of companies doing reconditioning only replace the failed component and clean it up a bit to make it look nice...

Personally, I have always (where availlable) fitted a new unit over getting the old one reconned. At least you know that it should be good for a fair while afterwards.

I think the component issue isn't one of trying to deliberately decieve and make a few quid, so much as using stuff which would be fine in most applications where the altenator doesn't get as hot, but in an Elan they don't get much airflow around them. Unfortunately, in modern society, many electrical componenets (starters, altenators etc) are cheaper to replace complete than repair - when a new one can be got for a similar price to a 'good quality' rectifier pack it's a choice of fitting cheaper bits or not doing the repair.

It would be worthwhile to speak to a reconditioner with your concerns and ask about fitting 'uprated' (which are probably more like OE than the 'downrated' stuff they use as standard) parts - the labour will be the same and the unit will be better suited.

That's some of the problem with comparing prices on the internet - unless you speak to them you don't know what you're getting.

Back in the '80s there was a local 'expert' who made most of his money by fitting a new set of brushes and painting your old unit with a black aerosol and calling it 'reconditioned' - which, in fairness, I suppose it was - if it worked afterwards

When the bearings in the altenator on my Vectra started squeeling i looked at getting them replaced, but the quotes I got made me think twice - and I bought a complete new unit for about £10 more than the repair price (but they have the advantage of volume of sale to keep the prices down) - with the Elan it isn't so simple.

Basically, a good repair will likely be as good as a new unit - as long as the wire windings are in good nick.