Human/Bike Powered Electric Generator

loki7714

loki7714

10 W
Joined
May 9, 2010
Messages
70
Hey all I'm in the process of turning my bike into a human powered electric generator. I've designed the bike stand (Yay Autocad!) and plan to build it soon. I also have a small 12v dc motor I plan to use as the generator (Came out of a 12v emergency tire inflator that plugs into your cigarette lighter.)

Problem
I want to use a regular old 12v car battery with a 12v inverter to harness the electricity made, but I can't locate enough info on the kind of diode I'd need too keep the electricity from flowing into the electric motor from the battery instead of vice versa. So any help appreciated. When i googled it I did see something about a Zener diode...

Also having trouble locating a small wheel that would be good for attaching to the shaft of the motor that will touch the bike wheel and spin the motor. (The smaller the better right?)
 
I doubt that motor you want to use will survive a side load for long, although without it bumping around like it would on the road, it may be OK until the bearings wear prematurely. I wonder if it even has bearings or is it just a bearing surface. Either way it's not designed for side loads on the shaft.

I second the alternator idea as that should be robust enough to be used in a friction drive situation.

Gary
 
Anyone?

P.s. My wooden bike stand idea totally failed so now im working on a pipe based one.
 
Zener diode is the wrong type to use for blocking. What you will need depends on the amperage it must pass. How many amps will the generator produce?

Also keep in mind that the blocking diode will have a voltage drop when conducting, reducing the voltage going to the battery. More data on the generator is needed. What is it's output voltage?
 
Will measure it as soon as i get it up and running but i doubt it will be a lot. Will probably substitute a car alternator in when this motor wears out as previously suggested.
 
I really don't think you want to even try a dc motor as a generator. There's a reason the auto industry changed to alternators half a century ago. Alternator creates ac voltage, and cannot act as a motor if back fed. The ac voltage is rectified to dc and regulated to battery charging voltage. If you get an auto alternator, try to get a single wire regulator.

You won't need a blocking diode for an automotive alternator.
 
Example

http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=9460

One wire, only have a single wire out to charge the battery (the case is the ground, negative wire). Oem style have 3 wires and require battery be fed back in to the regulator. Wiring diagrams can be difficult to find. One wire is just easier to hook up.
 
Ok cool thx! Ill have to look into what auto manufacturers use that alternator type for my trip to the local pull a part lol.
 
Pipe stand works awesome! Just need to screw it down to a sheet of plywood. Pics will be posted later.
 
Just for info, I picked up two LifeCycles from a bankrupt gym about two years ago. The recumbent I use for exercise in the winter; the upright I took apart to "investigate." Basically the LifeCycle provides the load to the exerciser by PWM ing the field of a small car alternator and having the output dump into a resistive load bank. Both exercise bikes have about a 400 or 500 watt 12 volt alternator in them, plus a very robust drive system with momentum wheel. If someone wanted a real human powered power source I would start with one of these exercise bikes.

Here is the alternator http://www.gympart.com/shop/itemdesc.asp?ic=LCA10&eq=&Tp=
 
coln72 said:
Like the idea. Looking to build some of these to charge batteries for the electrike trike I am building at the moment. Competition rules dont allow charging of the mains power :(

Tried driving an alternator off an old exercise bike but didn't have a big enough ratio to be effective.
Click to expand...

What do you mean by ratio? Bike wheel RPMs to Alternator RPMs? And by effective do you mean didnt work at all or was just not producing a lot of power?
 
Driving off the flywheel of the exercise bike onto a skateboard wheel attatched to the alternator. Wasn't a big enough ratio to get enough rpms at the alternator. It would work but not good enough for what we wanted, so we started working on mark 2 and 3. Then we shelved the electric idea for last year and went back to pedals for the trike due to reliability and time issues. Plus the flywheel wasn't perfectly round and bounced the alternator a fair bit.

Looking at using the back wheel of the bike as a belt pulley to drive an alternator this year but it has not been tested (or built :oops: ) yet.
 
I think the nicest pedgen I've seen had a treadmill motor. The builder managed to make 300w so I was impressed. 8)
 
This summer I’m riding off to visit family and cousins at our annual reunion. There isn’t any permanent power at the site. Instead of using a some rello's portable generator, I was actually planning on charging my batteries by putting up the rear tire on blocks and giving it a spin; regen in situ. The best part of my plan is that I know all the young cousins will want to ride my cool ebike, so I figure that if I could charge them a dollar per ride to see how much power they could make –I’d wind up with a charged battery pack and some chimp change left over for dinner. :mrgreen:

And now you know why my cousins calls me Kingfish.
 
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