Series no alternator charge or charge light

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monkfish24

Well-Known Member
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1,296
Location
Cornwall
I drove up to Plymouth from home the other day and the charge light was flickering when idling. There is now nothing. I've checked the fuses and bulb and they both work. I've checked the connections on the alternator and starter solenoid and all are tight and fairly clean.

It is a three cabled alternator and I'm guessing that the yellow and brown is The dash light cable. I've got two other cables which go to the same post on the starter solenoid. I'm assuming one is the sense and one is the charging supply? The post on the solenoid is the positive supply from the battery.

Apart from that, I'm stumped. I'm guessing it's going to be a new alternator? Any other ideas?
 
Charge light was flickering and now isn't lighting up at all? Even with the ignition on and engine not running? Could be blown bulb, dodgy connection or buggered alternator.Check the voltage across the battery when running with a test meter set to DC volts, should be 14 volts or so. If not it's new alternator time. Not too expensive or difficult a job.
 
I may be confused, but if the charge light is on it means that the battery is actually discharging? (This seems to be the set up on mine??)
A few months ago my idle was set way too low, to the point heel toe shifts were necessary to stop it stalling and when I used to take my foot off and as the engine became very slow the light came on.
Also it could be the fan belt ? Sometimes they squeak in a less obvious manor to what is usually expected.

To test the alternator, I would check the battery voltage, I would expect 12-13v and then turn the engine on, it should jump up to 14-15v as thats charging voltage
 
Don't bin the alternator until you've thoroughly checked the wiring, it could be a break in either the brown power or yellow / brown lamp wiring. Twice now and different motors I've ended up replacing alternators just to find its dodgy / intermittent / heat sensitive wiring....

Worst was carrying a fecking mahoosive alternator 10 miles in a rucksack on a scorching day in Hungary to first find a shop (I didn't speak hugarian and couldn't remember the German so had to take the thing) have it rewound only to find it still didn't work. Turned out to be wire the lamp wire that was held together just by the insulation which was making contact when the engine was off but the vibrations or heat were making it not conduct with the engine running so the lamp looked to be working but not keeping up with the batteries.

Theres a reasonable test procedure here: Alternator & Charging Wiring-Basic Tests - Electrical - The Mini Forum

If it is knackered new alternators aren't too expensive and if you're prepared to do a small amount of fiddling / fabbing a new larger capacity alternator can be fitted but sometimes needs a bit of packing and messing to get the belt to line up nicely. I went Woods Auto Electrics in Huddersfield and got a copy of a later 65 (I think) lucas for mine it needed a bit of grinding and a few washers to make it fit nicely and I ran new thicker wires back to the solenoid to take the heftier current.
 
The bulb circuit is the alternator excitation circuit, if circuit is broken no excitation so no charge.
If you remove the plug from alternator and switch ignition on then earth the yellow brown light should come on if it does not then trace that fault 1st before changing alternator
 
Just a quick update. I checked through the wiring and got everything I needed. Almost bought a new alternator but it all started working again.

Cleaned up the connector on the alternator and now all is working fine.
 
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