Morris Minor Owners Club

Hello
Just joined MMOC
Also purchased a Minor with this fault.
The Dynamo fitted has bolt-on connectors.
Could this be the early type and the source of low charge.
Regards
Tim

the type of connection makes no difference it's either charging or not. the only way to tell is with a meter to check the output.What makes you think its not charging properly,more info needed.

A 1958 car will originally have had those terminals. The dynamo is still a perfectly adequate charging system. I have the same on my car which is used almost daily. I assume you've checked the fanbelt tension already? The fault could also be within the voltage regulator.
Get the system checked out and the faulty part reconditioned would be my advice as so many of the new parts available are of poor quality unfortunately
Oh, And welcome to the club and Morris Minor ownership!.

Many thanks for your replies.
Only just bought “Hilda” so not a lot known yet.
Drove 30miles home and was stranded with a flat battery.
Checked the obvious things
Fan belt.
Brushes.
Battery.
The reason I wondered about the Dynamo is I notice two listed
C39. and C40.
Is their any difference in output ?
Regards
Tim

How old is the battery? The standard dynamo should supply plenty of power unless your running things like heated screens.

Battery age not known.
However charged up overnight showing less than 0.5A in the morning.
Sealed beam headlights, one reversing light the only extra.

Starts fine from cold.
NB Many thanks again.
I live near the Staffordshire/Derbyshire border.
Waiting for a ammeter to fit.
Tim

To answer your question, yes the earlier dynamo has a bit lower max. output. It has a bigger pulley which leads to lower rpm so the voltage increase with engine rpm is also slower. As said it should be able to charge the battery if everything is in order. Except as the driver manual states if the lights, wipers, and heater fan are all use it may not be enough to charge the battery. When the red light goes out that only means the output from the dynamo is connected to the battery after meeting the threshold voltage, but there is very little current produced until the rpms increase.

If you are charging the battery up to around 12.6v and it has lost its charge by the morning, then the battery is suspect. Take it to a battery place and have it checked over.
If the battery is OK, the dynamo can be checked by removing the fan belt and then removing the cover of the voltage regulator and pressing down the right hand of the two bobbins (as you face the regulator). The dynamo will then run briskly as a motor if it is OK. Don't touch the left bobbin (as you face it). Otherwise, if you have a mutimeter, you can check the voltage at the battery. With the engine running at a brisk idle, there should be around 13.5 - 14.5v at the battery.
If the battery and dynamo check out OK then, unless there is a wiring fault somewhere, the voltage regulator unit is suspect.

you can check the charge ,approximate, start it facing a wall and switch head lights on rev it and you should see the lights go brighter,switch everything on do the same and you should see the same result ,if not then charge too low .Take the car to any battery supplier and get them to test the battery and output,they usually do it free.no need to fit ammeter or voltmeter. Or by a multimeter and test your self very useful for many uses.

Hi. First post on this forum, but have been lurking for weeks.

I got a very original (though a bit tatty) 62 4 door a couple of weeks back and immediately had what sounds like a similar problem. Battery seemed to be getting 13.6V charge at fast idle according to my voltmeter, but was flat the morning after my first drive. Charged it fully, drove a short distance with lights on and then it was flat again immediately afterwards.

Then I realised the ignition light was staying on all the time. So I had presumably been discharging the battery, rather than charging it

Consensus from talking to a few bodies was dynamo fault, but the charge rate had seemed OK at idle when I first tested it, so I didn't know whether to buy that story.

New brushes perhaps needed, or may at least help? Ordered some to attack the dynamo, then decided to clean some connections up.

It was just a dud connection in the regulator. Took all off to clean up and one just fell apart. Corroded and poorly applied crimped connector. New spade plug and a clean up and all now (seems to be) fine.

Many Many thanks for all your replies.
I have been running round today with side lights and the battery is remaining charged.
So I am thinking with all electrics on this may NOT be the case !
I will be checking the regulator connections tomorrow.
Also since I have already ordered a ammeter I will fit it.

NB What a great forum this is !!!
Regards
Tim

well one problem with a dynamo is that unless you are running at a reasonably high speed ,not just stop and start round town,they don't cope well with all electrics head lights, wipers, heating,and radio on and only just maintain full battery,if dynamo is slightly down in output,or fan belt a bit slack ,then the battery charge drops ,slowly. That why many fit alternators,so consider this conversion if , when you fit ammeter the charge is low,no point in replacing dynamo .IF you are concerned about looking original there are alternators that look like dynamos,but a bit expensive Good luck

Welcome to the forum, Tim!

I'm also a relative newbie to the sport of Morris Minor refurbishment and there's a steep learning curve for sure but I'm sure you'll find the club an invaluable source of information. My car also has a dynamo but fortunately mine seems to work just fine although there were about half a million other things that needed attention! I decided to keep an online blog of my experiences in the hope that the things I've learned may help other newcomers. Feel free to take a look and I hope you find something useful there. https://castanley.wixsite.com/mysite

All the best,
Chris

Just found and joined your blog page Chris. Well done, and well worth a read for anyone new to, or rusty about basic Minor maintenance.

If the battery is OK I'd suspect an earth leak - they can be a devil to find, easiest way is elimination. On a modern car with multiple fuses its much easier. Sadly Minors generally have just two!

They typical life of a car battery is around 5 years, but the operating conditions affect that greatly. The type of car and engine are also factors, a modern diesel for example takes a massive amount of juice to turn it over when starting.
Extremes of hot and cold operating temperatures are also massive factors. When I lived out in Nevada, people typically changed their batteries every 2-3 years.

Bridgetj wrote: ↑Sat Nov 09, 2019 10:35 am Battery age not known.
However charged up overnight showing less than 0.5A in the morning.
Sealed beam headlights, one reversing light the only extra.

Starts fine from cold.
NB Many thanks again.
I live near the Staffordshire/Derbyshire border.
Waiting for a ammeter to fit.
Tim

Just looking at the post above
Charging rate only being 0.5A in the morning doesn't necessarily mean that it was fully charged, what was it taking when first put on the charger?
It started from cold, but was that soon after the charger had been removed, so battery still warm?

Batteries usually have a date label on them somewhere these days, if it hasn't got one then it's likely an older battery.

I'd be tempted to disconnect the coil supply and then turn the ignition and headlights on. Have a voltmeter on the battery terminals and see how it drops over a few minutes.
if you haven't got a volt/multimeter (get one maybe) then just see how the headlights dim over a period of say 10-15 minutes.
Then try and start the car, not forgetting to reconnect the coil

Thanks for all the replies.
I will try to sum up the situation.
BATTERY
OK condition because apart from one charge after driving home (2/11/2019)
it still turns the engine smartly.

REGULATOR
With A1 and A disconnected, and joined, voltage reads 15.5 between D and earth.
So checks out good.
All connections remade

DYNAMO
New brushes and serviced commutator.
No voltage checks Yet.

AMMETER
Now fitted.
Needle oscillates widely as revs increased sometimes.
Shows small charge with no lights.
Discharge with headlights.
Not easy to give precise reading.

Cables between regulator and dynamo OK

I have doubts about the Dynamo as said this is a early machine with nut and bolt connections. I am sure I read that the later regulator should not be used with early Dynamo.

Sorry to ramble on.
Regards
Tim

.

as already explained swap the dynamo or change for alternator

In addition to all the previous - if the battery is an open cell type (non maintenance-free) is the electrolyte level satisfactory and what is the SG?