Getting Cranky

Posted by: hikermor

Getting Cranky - 02/18/21 06:00 PM

I was just searching for items to augment my emergency supplies, funning across several items that featured hand crank mechanisms to recharge batteries. To me, those are a waste of time and energy.

I keep a very rudimentary bike mechanism on hand to use when I can't go for my daily exercise stroll. Now if I could find a foot powered generator or, alternatively, rig up some sort of gennie to my existing crank mechanism, that would be an alternative to solar power (even in SoCal, the sun doesn't always shine).

I rely upon the forum's collective knowledge and wisdom...
Posted by: dougwalkabout

Re: Getting Cranky - 02/18/21 06:08 PM

I think an old cordless drill could be adapted as a generator. It has the thrust bearing, gearing, and a permanent magnet DC motor. A switch between the battery and genny would be a good idea for when you stop pedalling.
Posted by: hikermor

Re: Getting Cranky - 02/18/21 07:16 PM

Interesting! The only cordless drill I have is still in use. Any references available for how to convert/adapt the drill?
Posted by: Blast

Re: Getting Cranky - 02/18/21 08:37 PM

Treadmill motors work as generators. You can either leave it attached to the track or make a frame for it to attach to a bicycle.
DIY Treadmill generator
-Blast
Posted by: chaosmagnet

Re: Getting Cranky - 02/19/21 02:43 AM

Agreed that a hand crank is sharply limited in its utility. It can power a low to medium output flashlight, or a radio receiver, but you'll get tired of cranking it fairly quickly. I haven't tried it but my best back-of-the-envelope guesstimate is that you could get a 5 minute emergency phone call for a smartphone for around 30 minutes of cranking.
Posted by: chaosmagnet

Re: Getting Cranky - 02/19/21 02:43 AM

Originally Posted By: dougwalkabout
I think an old cordless drill could be adapted as a generator. It has the thrust bearing, gearing, and a permanent magnet DC motor. A switch between the battery and genny would be a good idea for when you stop pedalling.


A corded drill might also be adapted for this.
Posted by: dougwalkabout

Re: Getting Cranky - 02/19/21 05:11 PM

Hm, I'm not sure about a corded drill. Do these have permanent magnet motors? I've never taken one apart.
Posted by: M_a_x

Re: Getting Cranky - 02/19/21 05:43 PM

Most donīt. They often have asynchronous motors.
I have had good success with stepper motors. I bought some cheap when they where on sale for coupling them with a Savonius rotor.
Posted by: chaosmagnet

Re: Getting Cranky - 02/19/21 06:38 PM

Originally Posted By: dougwalkabout
Hm, I'm not sure about a corded drill. Do these have permanent magnet motors? I've never taken one apart.


Good point! I understand that this will work with brushless corded drills but not ones with brushed motors.
Posted by: dougwalkabout

Re: Getting Cranky - 02/19/21 06:59 PM

Very interesting! I need to look into this further.