Morini Newby charging question

[Andy_C]

Bumblebee.

Sounds sensible fuse ratings given what circuits they are protecting - what about the main fuse in line with battery? Mine has a 25A fuse.

I popped the lid off the regulator box last night, the only things that you could perhaps replace are the 2 thyristors, everything else is "potted" in a grey substance, which was to be expected I suppose.

Once I have done the main fuse, and repaired the wobbly junction connector I will do another check of the charging voltage, given that all connections appear sound.

If it still fluctuates as it did, I had probably best replace the regulator.

One anomaly I spotted and that is a diode in line with one of the green wires from the connector panel (bottom row) not yet checked to see where the wire goes but I did check that the diode was OK and it was. Not seen this in any of the wiring diagrams. Anyone shed any light ?

[BumbleBee]

I don't know about the main battery fuse, I have owned four 31/2s the newest being a 1979 electric start model, not all at once, and none off them had a main battery fuse. Maybe yours was fitted by a previous owner? As you said, "badly"?

The diode in the green wire is protection for the electronic ignition system in case a voltage gets on the green wire. e.g. (1) In case the ignition switch develops an internal short circuit to green or (2) In case someone decides to put a tester with voltage on the green at the ignition switch terminals while fault finding. It wasn't fitted to early 31/2s but people sometimes retro-fit it.

[Andy_C]

Thanks Bumblebee - I always like to know what various bits and pieces do.

The in line battery fuse looks to be a "period" fuseholder, so may not have been fitted by the PO.

The electric start wiring diagram does show a fuse running from the starter relay to the fuse panel - fitting one in line from the fuse panel to the battery achieves the same result.

[BumbleBee]

Totting up the total load (and assuming the fuse can't possibly be protecting the starter motor ) I would suggest if you have a standard (45 Watt or less) headlight then a 25A main fuse is ok... but if you have a 55/60 Watt headlight it might be a bit borderline for the fuse in situations when all the electrical loads are running together.

[George 350]

Hi Andy,

Just a thought, but some multimeters can be affected by ignition interference and can give you odd/fluctuating readings.
Have you tried/can you try another meter?
Too high a voltage will overpower the battery and 'boil' the acid off. If battery is 'ok' it might be that you don't have a problem at all!

Regards, George

[Andy_C]

Good point George

The battery seems to hold charge OK, so perhaps I don't have a problem at all.

I do have an old analogue Multimeter, the checks I have done to date have used a digital one, I'll find the Analogue one and see what that says.

Thanks for everyone's help.

[Andy_C]

Final reply from me on this one.

Checking the voltage accross the battery with the engine idling it is around a steady 12v when the revs reach just under 2000 it goes up to a steady 12.5 / 13 so I am going to assume that all is well.