Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing + 4 battery not charging

HiTM'ers,
Advice needed from the group please.
I have a 1957 +4 with a TR4 engine.
The car starts on the button every time after charging the battery overnight.
It stays like this for a few days depending on how many times it is started.
Last night I charged the battery and this morning the Mog started as usual first time.
I took it along to the local car centre and had them test the battery on the car with the ignition turned off and then with the engine running.
Engine off showed 12.5 on the meter
Engine running made no apparent difference to the reading.
I believe it should be around 13.5 to 14 with the engine running.
Am I correct in thinking that the battery is ok and the problem is in the cars charging system.
If so where do I start troubleshooting, what should I be looking at?
Are there any obvious things that I can try before putting the car into a garage?
Auto electrics to me is a black art.
Any help much appreciated.

With a multimeter on a DC voltage scale you should as you note get around 13.5 volts with the engine running.

It appears your tester did not test the battery properly to do that, they use a device with a resistor in it to take 100 amps or so from the battery and test the voltage when the battery is doing that. It would be below 12.5 volts after a short period.

The next action you need to take is to clean all connections and tighten them especialy at the dynamo if you have not got an alternator and at the voltage control box if you again do not have an alternator.

Checking for a tight fan belt, I assume has been done.

After that a read at this MG pdf will show what is needed next but you may want an auto electricion to do the work.



http://mgaguru.com/mgtech/books/pdf/Lucas_Generator_and_Control_Box_Tests.pdf

You haven't mentioned whether your car has a dynamo or an alternator.

Dynamos, if I recall correctly do not charge as efficiently as an alternator and need higher revs to charge therefore taking a reading at tickover may be misleading.

If fitted with a dynamo, your car will also hVe a voltage regulator.

Is there an ammeter on the dashboard?

First let me thank you all.

Eddie: the fan belt is tight.I will have a read of the article. Im not sure it will mean much to me though. lol
David: to the best of my knowledge the car is fitted with a Dynamo.
tmg: there is an ammeter on the dashboard but I am pretty sure it doesn't work.
If it seems strange that I dont know the answers to some questions in my defense I have only had the car two weeks.

Seems like time for an auto electrican unless you are happy to play about with the electrics and you seem to be well out of your comfort zone.

Not a failure just not a subject fitting in with your skill set!

This might help
http://www.gomog.com/allmorgan/electricindex.htm

If it's a dynamo its likely to be brushes. Failing that, voltage regulators can stick, but it's one for the auto electrician if you don't know car electrica.
It might just be dirty connections.

ok guys thanks.
Spent a couple of hours removing electrical connections (one at a time}and cleaning them from the Dynamo voltage control box and anything else that I could see.
To be honest they look alright with no corrosion to my inexperienced eyes.
I have the battery on charge again ready for an auto electrician to retest.
I will ring tomorrow and ask one of the mobile ones in Grimsby to call.
As you rightly say Eddie I am out of my comfort zone.
If all else fails I will creep to the cemetery at midnight and bury an old penny and a dead cat on the last full moon of Autumn.
That should do it!
Electrical hocus pocus.

Wear a pointy hat.