Pedal powered generator recharging 72V battery pack, is it possible?

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shadow
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Pedal powered generator recharging 72V battery pack, is it possible?

Hello i'm looking into doing a project combining pedal power to a generator with a typical 72v lithium setup.

This would be extremely similar to many of the pedal powered 12V packs, but I haven't been able to find any solid information on what I need to do to make this work with a 72v lithium pack.

I know this would be possible by adding a second motor controller, and treating it like regen, but this is expensive, surely someone has a better idea on how to do this.

Gear reducing and such is possible in this setup, so rpm isn't a big issue, but i've gotten the impression by reading about motors that I can't simply just spin it as fast as i want to get the desired voltage as it will cause the motor to overheat.

I've seen some circuit designs for step up converters for this type of thing, but have no idea how efficient they are.

An adjustable setup would also be of great benefit, allowing people with greater pedal power to change the setting and dump more amps into the battery.

Anyone got any insight on this?

Spaceangel
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Re: Pedal powered generator recharging 72V battery pack, is ...

I used a 12 volt auto alternator and I could pedal it up to 4 amperes. Man was I tired and it was hard. 4 x 15 = 60 watts right? or is it Volt Amperes? A average HUMAN is supposed to be 76 watts? Right? So I don't know if you can charge 72 volts at high current? but 80 times one amp equals 80 watts? If you have the energy to build it and pedal it you might as well do it try it and post it on V. Are you Lance Armstrong? My 10 speed English bike has a 10 watt generator and I feel it slightly harder to pedal. and that is only a 10 watt bulb. I can't use it on Mtn. bike because of knobby tires.

KB1UKU

gasdive
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Re: Pedal powered generator recharging 72V battery pack, is ...

it will cause the motor to overheat.

That waste heat would come from the energy in your legs... Umm basically, forget it.

=:)

Jason
Blogging my Zero DS from day one http://zerods.blogspot.com/

shadow
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Re: Pedal powered generator recharging 72V battery pack, is ...

that's why i'm trying to see if anyone knows how to do this efficiently.

80V at 1 amp would work, the voltage is the important thing here not the amp draw

lbz5mc12
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Re: Pedal powered generator recharging 72V battery pack, is ...

I had a thought about this. I'm new to all this, so please no ridicule. Would it be possible to mount the generator on the bike and just run a chain between it and an unused gear? Then wire the generator so that your charger could plug into it. This way you could use your electric bike to recharge your pack while you're riding the bike. Just hook it up to the battery as though it were a regenerative setup. Another idea would be to use a second pack and charge it as you go. You know I just realized a problem with this idea. The freewheel on the motor would keep the gears from spinning if you're just using throttle power. You would have to pedal assist more or mount a gear on the left side of the hub without a freewheel. This is actually possible with hub motors that have the thread on disk break mount. I've found that a standard size one speed freewheel will thread onto the disk break mount. Of course you would have to seize the freewheel. Your best bet would be to get a gas bike gear that mounts to the spokes. This would also give you a larger sprocket which would spin the generator faster creating a higher charge with more output. You could use U-bolts and center mount the generator to keep weight off the rear wheel of the bike.

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