Jubilee fuse and capacitor

John, I have not done the 12v conversion on my Jubilee but I have fitted a Pazon ignition. You should read carefully the instructions from Pazon before fitting a fuse. You must not allow the engine to continue to turn with a power feed going to the Pazon unit, even momentarily, or current from the alternator will fry the electronics in the Pazon unit. Therefore, power to the unit should only be controlled through the ignition switch as that also cuts current from the alternator when the igition is switched off. I have a 25 Amp in-line fuse at the negative battery terminal, ie the feed to the ignition switch but mine is a 6 volt battery.

I am not sure about "losing the emergency starting", that may be so if you kept the original alternator and coupled wires together for a 12v output. I would be wary of using a capacitor in the igntion circuit as that may also overload the electronics in the Pazon unit. However, I am no electrics expert. Al Osborn of NOC is so he might like to comment.

Dennis

The 25A fuse in the main negative line is about right. The fuse is there to stop the comparative high energy of the 12V battery getting into the bikes electrics and bursting into flames. It won't protect your ignition amplifier very much as if that decides to to do an electronic 'whoopsy' the electronics will be long dead before the fuse decides to join in.

As regards the point about the position of the ignition switch within the circuit to the Pazon amp, surely this is the ONLY way one would feed any ignitions system? The way to understand some of this is as follows, 'initial concept'-ignore any rectifiers or regulator/rectifiers. There is a battery-power source. This feeds to an ignition switch and a lighting switch. When the switch is operated the light or ignition come on. Unfortunately in above 'concept' the battery after 50-100 miles goes flat-(walk home or get bus.) So we charge the battery with an alternator-rectifier or dynamo with regulator, this output feeds the 'bike' side of the fuse which also feeds the light switch and ignition switch. This is the basis of all bikes and cars.

The capacitor will NOT hold any charge after a flat battery. The capacitor is there to take the ripple-alternator bumps out of the system as they can trigger the ignition inadvertently. Again see the pdf on my web site for a fuller description.

Was a somewhat crude arrangement which connected the lighting coils from the alternator in parallel with the charging coils to give increased power allowing (supposedly) the engine to be started even with a flat battery. Oddly enough, the Ariel Arrow I had connected these coils directly to one of the ignition coils feeding it raw AC and I never quite understood how that worked.....

The Commando had the famous big blue capacitor in parallel with the battery. This, again in theory, would allow a start with a flat battery but I never managed it myself.

My 12v  coil ign  99  has lost the EMG  start  switching  arrangement . It will kickstart and run with a flat battery or even no battery at all  as the 2MC capacitor  facilitates that. Running without a battery would appear risky as the voltage  control  (Zener)  must be maxed out.

My Dommie has Lucas Rita replacing the mag. It also has Boyer power box to regulate voltage. If the battery goes flat I disconnect it temporarily to start it. If it is not disconnected, the alternator output goes straight to the battery instead of to the ignition. It's the equivalent of the 'emergency start' I suppose.