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Author Topic: Single wire alternator conversion?  (Read 62 times)


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Single wire alternator conversion?
« on: August 04, 2017, 10:03:08 pm »
Has anyone converted their Nuovo Falcone to a single wire alternator?  For example, the single wire Bosch 700 watt / 50 amp alternator used on BMW oilheads and K-bikes.  The stock setup seems to have a good reputation for reliability, but a modern, single wire setup would simplify wiring and provide greater output.

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Re: Single wire alternator conversion?
« Reply #1 on: August 06, 2017, 11:02:13 pm »
Haven't heard of one pg; one of our local owners is looking at fitting a mini-dynamo, having converted to a total loss system with a Li-ion battery, and missing the benefits of lighting. As you say, the stock system works, delivers sufficient power and is generally reliable. If my dynamo died, I'd probably replace it with another one, for simplicity


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Re: Single wire alternator conversion?
« Reply #2 on: February 18, 2018, 08:46:24 pm »
In reply to Patentgeek’s post about single wire alternators, here are details of something similar that I have fitted to my NF custom build.
Having said that, I do not encourage non original modifications to machines which are otherwise standard and perfectly capable of working efficiently with the standard equipment.
However my requirement was to replace my ‘dead loss’ battery system with something small and neat which would allow me to use my headlamp during both daytime and night time riding.
I came across (or should I say Banquo came across) a Kubota 12 amp permanent magnet alternator, as fitted to lawn tractors, etc.
It is very small and neat and driven via a standard Z 21.5” vee belt.

IMG_4190 by bancquo

As can be seen in the photograph it mounts on the standard dynamo mounting lug and just needs the addition of a small tensioning bracket at the front.
However it is not a single wire system. In fact it is a six wire system but it is all very simple to wire in place.
Because it is a permanent magnet device there is no control of output and so the spare energy has to be dumped through the separate voltage regulator, though heat loss.

IMG_4239 by bancquo

My voltage regulator is mounted under the saddle, on a heat sink (bit of sheet steel) in an area where there is some air movement.
Due to the small size of the alternator pulley the rotational speed is about 2 x engine speed. However on my bike, which is fitted with a smaller than standard rear sprocket 50 mph is equivalent to 2500 rpm. This means that the alternator will be doing 5000 rpm at normal cruising speed.
It remains to be seen if that will be too fast both in terms of bearing wear and heat dissipation through the regulator.
Time will tell !
Something that was really strange was that the purchase price from an Australian supplier was nearly £100 less than a UK supplier. But then I had to pay custom charges which did reduce the saving a bit.
Weird though !!!

So, to summarise, it fits very easily on the original dynamo mounting lug, and maintains the minimal look of the bike.

It's not road tested yet but everything is looking good at the moment.
« Last Edit: February 18, 2018, 09:54:59 pm by banquo »