Motorbike Stator Coil

Why not take it straight from the battery? (Asuming they are 12volt!!)

there is no battery, all lights will run directly off the stator coil

"The stator coil spits out an AC voltage obviously as it's mechanically powered from the motorbike crank.... I need to convert this to DC"

I'd think that any competent electrical engineer, electrical technician, electrician, electrician's helper, cable TV installer, motorcycle mechanic, motorcycle mechanics helper, hobby shop clerk, hobby shop janitor, garbage truck driver and just about any teenage boy on the planet could rectify this dilemma for you.

BTW, leave the training wheels on the bike.

yeah it's been many years since I studied, has anyone ever made a rectifier/regulator ?

well I've just been refreshing myself on electronics, and I think I've come up with a design which will work, I plan to solder up a full bridge rectifier with capacitor in parallel with resistor to have a near smooth DC voltage output, then feed this through a voltage regulator and hopefully obtain a constant 12V out for my lights!

Good one! Lyn.

Have you stuck a meter on the output to check the volts (and to check that it's AC)?

What did it read?

LEDs and a current limiting resistor will probably work fine.
You shouldn't need a rectifier... the clue is in the name Light Emiting DIODES.
Ok I havn't tried it and I don't know the breakdown voltage of the LEDs in question, but 5 minutes of experimentation is worth 2 hours of googling.
You only really ohms law and some leds to play with.
Failing that, just about any old bridge rectifier should do the job I'd think, but again... experimenting is the key and don't ground any wires, keep the led circuit completely separate from everything else it will simplify it.
I reserve the right to be completely wrong here... it's a long time since I rewired my old Lambretta, Mamma mia, she's a long a gone to scooter heaven
Del

Do bear in mind that any modifications to the vehicle must be reported to the vehicle's insurers lest a different premium is payable for the cover for a modified vehicle.

Also, in the UK, all modifications away from the original manufacturer's specification must comply with the annual MoT test requirements for the vehicle to remain on UK roads. There may be similar requirements in other countries.

So, just headlight and lail lamp? No brake light?

In most places, this means still not street legal.

Most off road Motorcycles have an Enduro/Road equivilant which would have the relevant lighting coils.These can usually be obtained fairly cheaply from Bike Breakers /Wreckers and would fit directly or with very little work.The same with headlights/tail lights to conform to Road licensing laws if applicable.I wouldn't have thought an AC flywheel Mag setup capable of being reliable with extra loading as any moisture (rain) can play Havoc with generation.

For about 50.00USD you can buy 2 high output/high quality bicycle lights. One white one in front for a head light, one red on in the rear for tail light and 250.00 left over for batteries.

Tobuqrynbak:

Diode Trio, rectifier bridge, V-reg. keeping in mind feedback to the A/C circuit that fires the coil. usually a magnetic switch. Quite a bit of work actually and General increase of impedance in the coil circuit weakens the output. Overall the wattage required to power the lighting is nada compared to what it takes to run the circuit. If

Kind of like NASA, eh.∑

Sundog

I must agree that anyone with a title 'electrical engineer' would not need to ask such an elementary question. I also fear that IF the coil supplies both the ignition AND the proposed lights, the ignition may suffer, particularly at low revs. I had a Vespa scooter in the 50's but it had a separate coil for supplying the lights.

Penttijp

I think the ignition will suffer more at high RPM/high load than low.

I say this because_{(in my misspent youth)} I had a Kawasaki KZ400 twin, and when I ran WFO at night the lights almost went out. When I backed off the throttle the lights got bright again. (I mis-spent my youth well into my 30's.)

Why not just obtain a set of clip-on bicycle led lights which use 2 aaa batteries each, last quite some time and cost about 5 dollars for the set. Thought: there may also be some transient spike voltages in the stator coil since it's part of the high voltage spark coil circuit. Easiest, most economical solution would be self powered bike lights.

That was my thought too. If AAA batteries are not enough, get a small gel cell and strap it down somewhere and use the 12v. Seems a much easier and simpler solution. (But then I'm a simple person) You could probable fashion a bracket in less time than you could make the necessary circuit to use the stator coil.

(Just a side note on obtaining gel cell batteries. Here in the North East USA we have "yard sales" and quite often people sell off used kids toys (little cars that kids drive) with gel cell batteries in them or the batteries themselves. I've obtained several with 12v and 8 to 12 AH for less than $2 each.)

Tom

They sell complete kits for bikes, including: light, mount, (from screw to glue) and batteries. The headlights are quite powerful and removeable. I often ride my scooter here at night cause well, it's a Maui thing. To supplement the existing lighting wear one as a (human) headlight. Strangely enough the main problem is too much light which can really tick off oncoming drivers. I say this only in respect to the mention of money (value), so it has draw backs, as soon as I think of one I'll let you know. .... peace, sundog

Strangely enough the main problem is too much light which can really tick off oncoming drivers.
The problem is not too much light. It's the proliferation of sociopaths.
These sociopaths cannot resist the temptation to look at the car heading for them, and turn their head, aiming their headlight into the driver's eyes. Its not too much light, its incorrectly aimed light.
Did I read that you can now get fined $11,000 for shining a milliwatt-level laser at an airplane?

Correct

But I got away clean and all is well.

Sundog.

The stator coil spits out an AC voltage obviously as it's mechanically powered from the motorbike crank...

Gives a whole new meaning to the term stator!

The electrical end of this is a no-brainer, (especially with the existing comments) so I won't add my tuppence.

But I would advise that you consider the utility of the light. Where you live, it may be possible to make a bike "street legal" with just a feeble headlight and taillight. But there may come a time when you actually want to use the headlight, and at that time you may find yourself riding without enough light output. Stay down around bicycle speeds and you'd be OK for picking out a path, but you would not be as visible to oncoming drivers as you would be with a real headlight. (1000 lumens is probably a reasonable minimum output for a single headlamp. HID lamps [as used on well-equipped cars] are more like 2500 -3000).

It is worth checking for a street-legal version of the same basic bike. These typically have a real lighting coil (separate from the ignition coil) a rectifier/regulator unit, a usable headlight, a small battery, etc. Often the flywheel is a little heavier, making the bike a little easier to ride at lower speeds.