Those Crank Powered Radios

One novelty item you will see advertised on prepper sites and spam emails are Crank Powered radios. Some of them also come with a small solar panel mounted on the top. These are novelty radios and should not be taken seriously as reliable prepper radios.

This radio performs as a radio should with the exception of the solar/crank system

Why am I busting on these crank radios? Have you seen the bearings and brushes on the inside? There aren't any good roller or sleeve bearings and they are cheaply made. Sure they might work for awhile but you will soon find the shaft will seize up or spin freely with no power generated. Some have plastic gears which will disintegrate. Is that what you want your life to rely upon? Have you ever listened for a half hour and counted how many times you had to crank the radio and how often?

All these off shore crank generators have a life span from about 10 hours to maybe 30 hours before failure. The measly little solar panel option is fair but the radio and its plastic enclosure probably won't withstand direct sunlight for a long period of time and the radio will overheat.

So what's the answer? It would be best if you purchased a separate and larger solar panel with a simple charge controller and plug it into the radio to charge the rechargeable battery in the radio. Plus it will take less time to charge and you can shade the radio behind the panel so it doesn't burn up. You can also use the panel to charge up other items like flashlight batteries, cellphones, ipods, etc.

A good panel would be about 12 inches by 12 inches that would produce about 18 volts at 1/4 amp. To speed up charging you could use multiple panels connected up in series or parallel if connected properly. Please visit this site to learn how this is done.

If you are insistent on using a crank generator there is a very reliable method. Retrofit a stepper motor and rectifier stack and make a simple hand crank for the shaft.

You can crank for years without wearing out the bearings because the bearings are designed for almost continuous duty and produce higher output power. Stepper motors can be purchased on Ebay for very low costs and can be gotten from small ones the size of 1 inch square cube to a full size one, the size of a 12 oz soda can. You can also scrap an old dot matrix or laser printer. There are at least two if not three stepper motors inside. The bigger the printer, the bigger the motors. For small demos even old floppy drives had a stepper motor.

Hooking them up is quite easy. Stepper motors are usually 3-phase motors. You will find three pairs of wires which make up the three poles. It will require six diodes to extract the most power. 

Here's the rectifier configuration wiring.

A good propeller can be fitted to extract wind power too. I have even seen these steppers fitted to a stationery bike to get the most power out of it. Your imagination will come up with a simple hand crank or foot crank system.


Copyright 2021 by Rick C. Ver 0.12 Jan 31, 2021