Generator idea.

[MotorMac]

Alt

That looks like it would work, although I think you would also need some kind of voltage regulator?
Also some kind of custom mounting bracket too to fit on the bike frame, perhaps turned by the back tire?

 

[duivendyk]

That would seem to have potential,price seems reasonable, probably capable of 15V + at 1-2 amps continuous,at what rpm?,good question.Remember output Voltage proportional to rpm.Would need battery charger IC or some sort of regulator to control charge current and prevent over charging.

 

[duivendyk]

Another candidate is a 12V permanent magnet car blower motor,either the radiator fan type or the internal one.They will act as dc.generators when driven.You can produce 6V,dc. at 1+ Amp with one,to get 12V under load probably takes too high an rpm.The radiator fan types are gutsier.They usually have brushes which is not too great eitherNeither type probably has bearings that can support much of a sideways thrust,like a friction drive.But you can prob.get one for a few bucks at an auto recycling establishment (junk yard)
As with the previous types, a voltage/current regulator is required.

 

[loquin]

An auto alternator doesn't use permanent magnets for the magnetic field - it uses 6 coils of wire as electromagnets. And, it adjusts output voltage by adjusting the current to the field electromagnets, and thus, the field strengths. Alternators came in to use primarily because coils of wire were cheaper than the large, powerful magnets that a generator needs.

A fractional horsepower 12V dc motor would be ideal, as you wouldn't need a complex regulator circuit to adjust field current. You would need a simple regulator/charger circuit to charge the battery, and to prevent overcharging it.

 

[lordoflightaz]

That would seem to have potential,price seems reasonable, probably capable of 15V + at 1-2 amps continuous,at what rpm?,good question.Remember output Voltage proportional to rpm.Would need battery charger IC or some sort of regulator to control charge current and prevent over charging.

Did you notice shipping charge LOL

 

[duivendyk]

For the record, car alternators generally have a single field winding not 6 separate ones,they do have 6 poles and need to be allways connected to an live battery,in order to provide the excitation for the regulator& field.Most car alternators have a built-in regulator nowadays,but I don't know if that is the case for the motorcycle variety.

 

[crazyman]

At riding speed, what kind of voltage does a computer fan put out?

 

[lordoflightaz]

At riding speed, what kind of voltage does a computer fan put out?

I don't know ask me again in a week or so, LOL I still have to get the bike running before I get to that point. I am sort of working that out. I have a fan motor that I have stripped down to just the motor and the wires. I just have to figure out how to connect it up. I also have a few CPU fans that I will look at as well. It needs to stay under 14 volts and it should. I needed over 9 volts to get it to spin as a fan on a set of serially attached solar cells.

In any case will have to watch out if it spins to fast and explodes. I plan on shielding ME from it when I mount it.

Plan is to charge a litium ion battery and run lights off battery.

I do know that spinning a similar motor put out over 12v when I used an 18v ryobi drill to spin the motor. I lit a string of LED lights with no problem.

I do have a Harbor Freight solar voltage regulator that I can use when this boondoggle gets farther along so I could also throw on a couple solar panels to generate more energy when summer rolls around, comes with 4 output jacks including USB

 

[5-7HEAVEN]

That looks like it would work, although I think you would also need some kind of voltage regulator?
Also some kind of custom mounting bracket too to fit on the bike frame, perhaps turned by the back tire?

I thought about spinning it off the tire, but alternator rpms would be up to 7000rpm at top speed.

I thought about installing another 18.75:1 output shaft on my Staton chain drive gearbox. However alternator rpms would drop to 107 rpm at 2,000 engine rpm, 427rpm at 8,000 which is too slow.

So I'll drill the box and install Staton's intermediate output shaft for 5:1 gear reduction. Seems perfect with 400 rpms at 2000rpm, 1600 rpm at 8,000 engine rpm.

I need a mounting bracket above the Staton box, 1:1 pulley,matching belt and voltage regulator or diodes.

 

[5-7HEAVEN]

What's unusual with this alternator is that the pulley and body are one-piece plastic. The flat endplate is stationary and has three threaded hloes for mounting purposes. Two wires exit through the endplate:

http://cgi.ebay.com/ebaymotors/New-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories



I called Dave Staton a few months ago and asked if it was possible to modify his gearbox to install another output shaft. He said it was simple to drill a 5/8" hole thru the Staton gearbox. Then you replace the gearbox's 5:1 intermediate shaft with one having a 1/2" or 5/8" output shaft. The intermediate shaft's existing bearing serves as a pilot to drill the 5/8" hole and can be reused to support the new 5:1 output shaft. This is the installed Staton intermediate shaft which sells for $29.95:

http://www.staton-inc.com/Details.asp?ProductID=3257

BTW, you can convert Staton's outside-drive gearbox to inside-drive AND outside-drive by drilling thru the gearbox and installing the appropriate output shaft.

I used to fret about having an outside-drive gearbox. I thought I'd have to buy the inside-drive gearbox to install a NuVinci hub. Thankfully, all it takes is a $29.95 output shaft from Staton to retrofit his gearbox. That saves having to plunk down $300 for a new inside-drive gearbox.