Pride came before a fall. Advice please.

[MikeParker]

I will go against the flow here. While your battery may well need changing after ten years, that is not the main fault. Your alternator should provide enough current at idle to run the basic functions needed to keep the engine going. Ideally it should also provide enough for dipped beam headlights /wipers etc also. If not, your battery will always run flat eventually. A new battery will just take longer to go flat. It will also shorten its life through too many charge/discharge cycles. So the test is to check that your battery volts stay around 13.5v even at idle. You can also see the problem by seeing if your dipped beam headlights dim at idle and then brighten as the revs rise. I had a similar problem where dipped beam plus wipers going would cause the volts to dip. The cure was a new alternator. Modern alternators have a higher current output and a higher output at lower revs so should cure the problem.

[MikeParker]

This thread is appropriately named. Talk about pride coming before a fall.. Above I was extolling the virtues of new alternators. Well, went out to start my Stag this morning and .. no charge. Ignition light not going off and battery volts staying at 12.4V. Having whipped off the alternator the problem was the new alternator I fitted only 2000 miles ago. The copper braid wire to one of the brushes had become detached from the metal connecting strip and so no current was going to the rotor. It was spot welded on and here lies a problem of many new spares. The quality simply isn't there. I soldered it back on as a temporary fix and I will see if I can get some decent quality brushes. I should add, that my alternator was not sourced from any of the well known Stag suppliers but from a cheap on-line source, because I needed it urgently.

So the lesson is, get a new alternator, but try and find a decent quality one!

Mike

[jakesmig]

......... not so easy to jump start many thousands of tonnes of ship rolling around mid-Atlantic!
Stay safe,

Neil.

I saw a fishing boat tow start another fishing boat going out of Carradale harbour back in '74.

Another bizarre sighting was seeing a water skier in Ireland being pulled along by a horse, that was in '70.

Both true.

John.

[DJT]

This thread is appropriately named. Talk about pride coming before a fall.. Above I was extolling the virtues of new alternators. Well, went out to start my Stag this morning and .. no charge. Ignition light not going off and battery volts staying at 12.4V. Having whipped off the alternator the problem was the new alternator I fitted only 2000 miles ago. The copper braid wire to one of the brushes had become detached from the metal connecting strip and so no current was going to the rotor. It was spot welded on and here lies a problem of many new spares. The quality simply isn't there. I soldered it back on as a temporary fix and I will see if I can get some decent quality brushes. I should add, that my alternator was not sourced from any of the well known Stag suppliers but from a cheap on-line source, because I needed it urgently.

So the lesson is, get a new alternator, but try and find a decent quality one!

Mike

I went through 3 alternators in quick succession a few years ago. A local factor sent my original one away for reconditioning, it failed within a week of return. They replaced it and that lasted less than 2 years (7250 miles) - out of warranty! Bought another, and that failed after 2 years, 3 months (7,500 miles) .Bought a repair kit and did it myself. That's been in use for 23 months (7500 miles) now. Fingers crossed that it keeps going!

If it does fail, I'll probably go down the A127 route. At least this website admits that there are quality differences in the ones they sell: £50 vs £170: https://www.autoelectricsupplies.co.uk/product/908

[flying farmer]

I have fitted several cheap "lucas" alternators over the last few years to various cars.

I have had the odd good one, I think. One on the TR failed after a couple of years but I was bouncing it off the rev limiter doing the Autosolo at Lincoln at the time and fortunately there was a stand there selling cheap "lucas" alternators. He looked at me a bit funny when I said it had only lasted a couple of years but was probably cheap chinese sh1t

I fitted one to my K reg Stag when I built it 3 or 4 years ago, it was still working but at idle all the lights flickered. I decided to try swapping the voltage regulator out of the ancient original Lucas one that suffered a seized bearing coming back from Stoneleigh this year (burned through the fan belt, fortunately the new battery got me home the last half hour).

Unfortunately I couldn't find the correct back half in the pile of knackered ones and after trying two different ones that didn't work I gave up and refitted the original one. Oddly this now works fine so it must have been a dodgy electrical contact.

I bought another cheap one to replace the one that seized. This had a rotor that touched the casing so contacted the seller for a replacement. I had already binned the packaging but they sent another and let me return the first one in the second ones box.

Unfortunately the second one had a pulley that was drilled so far off centre the fan belt would have been like a skipping rope and a front bearing that clicked as it rotated. Not wanting a third turd I made one good one out of the two and sent the sad remnants back to the seller who if he had any sense would lob it in the bin

For some reason I am now reluctant to try another cheap one!

Neil

[MikeParker]

Just checked back in my records and the cheap one that failed today was bought off eBay for £42.95 plus £5.95 P&P back in July 2019. It was sold as a high output 55Amp alternator. It lasted about 2000 miles whereas the original lasted 155K miles and was still working at the end (albeit with a change of brushes at 80,000 miles). The problem with the original was that the battery went flat with lights plus wipers on - i.e. just when you don't want a stuck car - on a wet and dark night.

Having taken apart my cheap alternator all looks fine apart from the brushes described above. I have fixed the broken brush wire and measured the battery voltage when running and it shows how well modern electronics work. At 800 rpm idle with no extra loads the battery voltage is 13.95V. With dipped beam lights on the battery voltage only goes down to 13.55V. So still charging the battery. My original alternator was in discharge territory under these conditions. Interestingly, the voltage as displayed by the dashboard voltmeter goes down further to about 12.5V when the battery voltage is 13.5.

[Neil in Deal]

Evening all,
I was at the NEC Classic Car show in 2018, and one of the commercial stands, whose name I cannot remember had items like coils and alternators done in "section" revealing the poor-quality of some, compared to the obviously better quality of their own items. They were not manufacturers themselves, but their message was one of that they checked the physical and electrical quality of the goods they supplied. In particular, one "el cheapo" coil looked horrendous inside, poor connections and the wire of the windings looked really small in diameter, wouldn't think that would last very long. Still, you'd like to think an alternator would last slightly longer than some of the ones above....and certainly NOT have having poor bearings and/or pulleys out of true etc. The phrase "hand-crafted by artisans" comes to mind !!

[jbuckl]

I had an alternator from one of our respected suppliers. It failed after 2miles (diode fell out) the suppler wouldn’t replace unless I bought another one outright as well. So I did. That one also failed almost at the same place as the previous one & with a loose diode again!
so I took the original to a local auto electrical shop & asked them to repair it.
they said they could, but it would be more money than a new one from China, which they recommended.
i went with the new Chinese one and it’s worked well for many years & 26,000 miles so far.

[dasadrew]

I went through 3 alternators in quick succession a few years ago. A local factor sent my original one away for reconditioning, it failed within a week of return. They replaced it and that lasted less than 2 years (7250 miles) - out of warranty! Bought another, and that failed after 2 years, 3 months (7,500 miles) .Bought a repair kit and did it myself. That's been in use for 23 months (7500 miles) now. Fingers crossed that it keeps going!

If it does fail, I'll probably go down the A127 route. At least this website admits that there are quality differences in the ones they sell: £50 vs £170: https://www.autoelectricsupplies.co.uk/product/908

Had to chuckle...

Monty Python Holy Grail:

"Other kings said I was mad to build a castle on a swamp, but I built it all the same. It fell into the swamp. So I built a second one; that burned down, fell over and sank into the swamp; but the third one stayed up, and...."

[Stagdad]

If after you jump started and drove home you had topped up the battery and it held charge until the morning that would suggest it wasn't all down to a poor battery.