I got my Morris Minor five years ago and have been daily driving it since (it’s my first car). I have done an alternator conversion due to how often I use the car, plus I have halogens fitted, a speaker, USB port.
I’m writing this post from the hard shoulder on the M62, because once again I noticed lights dimming, and indicators flashing very slowly. I pulled the starter and no life in it. Battery is at 9.8V testing with my multimeter. My fan belt is not slipping.

This is a pattern which I can now consistently predict will happen every 9 months or so, and I only average 2.4K miles a year. What I would do is then charge the battery, and replace it with a Chinese made Lucas-type alternator ordered from a reputable well known Morris parts supplier. I have been through at least five of these in 12k miles of ownership. Eventually instead of replacing the whole unit I would just replace the regulator, which would temporarily fix the problem for a few months (back up to 14V) and then fail.
This last April 2024, it went again, so I thought it must be the sub par quality of these Chinese alternators. I instead bought a £200+ WOSP top of the line OEM standard Lucas type alternator to try to permanently cure this issue. And I also put a plug in to cigarette lighter voltmeter to give warning of upcoming failure.
I have noticed a pattern of it working fine around 14V without headlights on in the day. Then at night when I put headlights on it will stay at 14V for a few minutes and then drop down to 12-point-something volts, and then gradually decrease. If I turn the headlights off and start it up again, I will not get 14V and it will stay the same as it was around 12V or lower depending on how far I have ran it. However the next day, with the headlights off, I will start it up and it will charge and run well at 14V again. I was able to do this on short runs for a good few months. I took it to KwikFit to get the charging system tested, and they couldn’t find anything wrong with it, so that gave me false peace of mind to keep using it. Battery tested healthy just a couple months ago.
Earlier today I did a short drive in the day and it stayed around 14V. Later on I started a 2 hour journey in the dark with lights on. Started at 14V and soon dropped down to 12.8V and then gradually dropped to 9.8V over a period of about 1hour 45 minutes driving with headlights on, then I stopped on the hard shoulder which is where I am now because I knew something was wrong and found a safe place to stop (Smart Motorway is just ahead from me!!)
Luckily this WOSP alternator is under warranty. My mates in the MMOCYM haven’t had any problems with the Chinese alternators and my car is well known with them for the failing alternators. I think that something with my car is causing them to fail, it can’t be just bad luck, especially now this expensive alternator has failed on me.
I have tested the resistance from alternator to battery positive, and fitted an extra earth wire from the engine directly to the battery negative wire at the top there. No problematic resistances on either side. I have replaced the bullet connector earths on the headlights with ring connectors to improve earthing.
I believe replacing the alternator will fix it temporarily, but I don’t trust the new one not to go again. This WOSP one,(more than three times as expensive as the ones from morris minor suppliers) has barely done 3k miles! They only last 2-3k, that seems to be the magic range for them.
Any advice? I done countless internet forum browsing over the last five years and I’m at a complete and total loss on what to do, when the next day it’s 14V again and tests come back all is well.
Thank you very much, I hope your Moggies aren’t as temperamental as mine. Hopefully breakdown will be here soon!

If anyone would be interested in taking an actual look at it I’m at Liverpool.
(As I write this I can’t post due to cellular date ip range being blocked, I will post as soon as I get home)