[Adrian II]

As far as I'm concerned, the capacitor solution came from Mr Pete Snidal himself :

Fitting capacitors instead of batteries actually goes back to the British bikes of the late 1960s. The Lucas 2MC capacitor became popular once BSA and others started fitting 12V systems to e.g. the BSA Victor Special. My first rewire was of a BSA C15 from 6V to 12V in 1977 with the 2MC capacitor.

If you wanted to run a 6V alternator bike without a battery (and not convert to 12V) Lucas would sell you an alternator designed for their notorious Energy Transfer system. I say notorious because it the timing was critical to avoid bad starting. 12V and a capacitor was much more forgiving.

Of course we are talking pre-UCE Bullet here so, there is yet another option, at least for the ignition!



A.

[stinkwheel]

Out of interest, I decided to check if there was any resting current leakage on my bike when a capacitor is plugged in in parallel with the battery.

The answer, none at all. At least none measurable with my meter which goes down to 0.1μA (which is sensitive enough to detect the current caused by waving the meter cables about in the earths magnetic field).

Never seen a bike with zero resting earth leakage. I suspect this is because the reg/rec connection is upstream of the ignition switch on account of having to run through the ammeter. There's usually a tiny (few milliamp range) resting current leakage on motorbikes which I take to be a minute backflow through the zennor in the reg/rec (because a diode doesn't block current until you apply some current).