yet another generator idea

For the 6 volt one with 3 watts, you'll have 500mA.
Has no one built a generator yet? Hmm..

Oh my, that's a heck of a lot of amps. Is that inside a battery? Keep in mind there is no free energy. The energy these engines create put their energy into turning the wheel. If you are going to use the crank shaft, you're going to pull away from that energy and put it into "electrical" energy instead of mechanical. Essentially reducing power on the motor.

Im not sure by how much though. 12 amps is quite a bit of current at this scale so whether or not it'll be a noticeable amount of power loss im not sure. So with your alternator idea, are you planning on charging a battery or having it go directly to the lighting system?

I'm working on one now using a 6volt 3 watt bike generator. I haven't fired up the motor yet, but here is how it was done (assuming it'll work):

I have an EZM Q-matic kit and I fashioned a bracket that mounts off one of the bolts on the clutch bracket on the left as viewed from the rear.
It is powered off the rear primary pully and I dug around for a thick rubber O-ring to go over the grooved roller on the generator, so that it wouldn't be metal to metal.

One of the important things is that the generator has to have a "floating ground" . Mount the generator to the bracket with something rubber.

What I mean by "Floating" is...the generator is AC, one instant current goes "out" the center terminal, and in thru the bracket. The next instant it reverses...going back "in" thru the center terminal. If you are going to have it go to batteries, the batteries will be grounded thru the bike and you want to isolate the generator otherwise when you go to hook up the batteries, the batteries will short out. Why do I say "batterieS"? More on that in a sec.

If you want to run a 6v generator and get 12 volts, you need 2 rectifier diodes (1N4007) or at least current capacity twice generator saturation current, which is 1/2 amp...so basically 1 amp or more.
follow the chart on www.amphibike.org/index.cgi?page=pages/3_bikes/monocog/unregCharg

The chart is "Split wave full charging" circuit. You put the 2 diodes coming out of the center terminal, 1 with the flow out to the (+) of 1 six volt battery, and the other reversed with the flow "in" off the (-) terminal of the 2nd battery. The wires on the other sides of each battery hook to the generator bracket.

The diodes allow current to flow only 1 way, in effect turning it to DC current. You can test this by using a Multi-Meter on DC. as you spin the generator, no response. Attach a diode...Lo and behold, the needle moves!

What is happening in this circuit is: If you know what a Sine wave is from Trig class...The outflowing diode is charging the first battery off the top of the AC waveform, and then reverses sending current to the 2nd 6v battery off the bottom waveform. This is the key to get 12v out of a 6v generator.

You need 2 6v batterys. Current capacity shouldn't matter. I'm going to use a couple of small 6v. scooter batteries. That bike generator is designed not to overcharge whatever it is powering, so regulation isn't necessary. When mine is done, I'll let everyone know how it went. Good luck (WHEW)

thegnu said:

yes to charge a battery then run out to the lights .
an midwest thats a lot to digest ! so I know why you said {WHEW}
The battery I am using now is a 7.5 amp hr sla , also I have dioded the white wire an built a full wave bridge rectifier but its little more than a trickle charge to that battery now . I have been learning this electrical thing as I go , I can repair them in automobiles all day long but designing a system from diddly squat has thus far been a challenge . my basic idea is to drive a small gen or alt off of the crank out put on clutch side via a small pulley to an external config. I know the answer is out there its just a matter of putting the right combo of info together .

Click to expand...

You may not be getting much of a charge out of that now because of the diodes. You could try getting more efficient ones. A single silicone diode drops voltage by about 0.7 volts. Significant for what our engine makes. You should test your voltage after the circuit you have made. Wouldn't hurt to test how many amps it creates either.

really? I thought the white wire only produced 7.5 volts?

Oh huh. I'd imagine you could use a 12 volt battery then. 500mA should be more than enough to charge a battery and run lights. Since the lights would only be in use during night you would make up enough during the day time when you are riding.

I dunno, seems like it would work to me but maybe there's more to it than what I am thinking