Misc: Charging Systems Series ‘C’ Rapide Battery Not Charging

danno

Well Known and Active Forum User
Non-VOC Member
Hi
The red charge light on my C Rapide isn’t going out whilst riding. The ampere meter is showing 2 on discharge.
The bike is fitted with Lucas Rita 12v ignition and while it starts ok, the battery is showing 10.5 volts after a run.
I’m not sure whether it’s the battery or the charging system that’s the problem.
Any help appreciated.
 

Robert Watson

Well Known and Active Forum User
VOC Member
I think everyone is going to want to know what you have for a charging system and voltage regulator before any worthwhile comment can be made. I will tell you that Lucas Rita \ignition systems do draw a lot of power. I am surprised that it only shows 2 amps discharge, I would expect at least 3 and with a battery down to 10.5 Volts are you getting any misfiring? More info required!
 

danno

Well Known and Active Forum User
Non-VOC Member
Thanks for the reply. I’ve inherited the bike and tbh I don’t know what charging system or voltage regulator it has, or where they are.
There’s a box bolted to the rear mudguard as shown in the pic. Possibly connected with the ignition system.
There is some popping from the engine on the over run but it’s always done that.
 

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vibrac

Well Known and Active Forum User
VOC Member
Ah is that a JG regulator I see ? unusual position but easy to get at when you throw it away (IMHO) I will let others advise you on replacements I have a Alton or a walkenator
 

Robert Watson

Well Known and Active Forum User
VOC Member
Can you post a picture of the generator and perhaps the red light (it did not come with a light so that has been fitted as an extra). If you are not familiar with motorcycles and wiring you definitely should join the club, find the local lads and take some advice. A 6V generator (original fitment) wired to put out 12V will work, until you hits some sustained speeds with the bike, then it will cook the armature and fly apart, but it may have had the armature changed to a 12V one. I only had one bike with a JG unit and although I have not heard much good about them, the one I had worked well. There are better constructed systems out there, especially if the bike is inherited and hasn't drained the bank balance just to get it and put it on the road!
 

danno

Well Known and Active Forum User
Non-VOC Member
Thanks
I’m familiar with motorcycles and wiring just not with Vincents. The bike was fitted out with electronic ignition when it was restored by Conway Motors back in the nineties.
There’s a brass cylindrical unit below the battery tray (shown in pic) that is connected inline between the battery positive earth and the electric starter motor. Also has a loom attached.
 

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Simon Dinsdale

VOC Machine Registrar
VOC Member
VOC Forum Moderator
It looks like you have the original 6V Miller dynamo which has been converted to 12V by using a JG electronic regulator which is the aluminium box bolted to the mudguard. My bet is the JG regulator has failed which was a common occurance with JG and today there is a lot better electronic regulators available. If you are not familiar with the workings of a Miller dynamo converted to 12V and how to test it then it will be easier to contact the VOC section local to you and see if anybody who is more familiar with it can help.
 

Peter Holmes

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VOC Member
The brass unit that you refer to fitted underneath the battery is almost certainly the starter motor solenoid, it is not brass but plated steel, it does have a brass look to it though.
 
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