The K-Tor Power Box
Pedal Powered Generator
One of the more memorable scenes from the 1973 film Soylent Green was Edward G. Robinson on his pedal powered generator, to keep the lights in a post collapse scenario. Is pedal power realistic? How much power do you get? We we able to try the $195 extremely innovative K-Tor Power Box, one of the few complete package options on the market. It generates 20 watts at a steady pedal rate. This is not a ton of power, but lets take a look at the actual numbers, plus a general review of the product itself. One of the nice features on the K-Tor is that it generates 120 volts, not 12v like most backup power systems. The power is DC, not AC, but you can plug your regular wall warts right into the K-Tor, because DC will pass through the power rectifiers in the wall wart. Most electronic devices run on DC, but electric motors are generally AC.
The watt as a measure of electricity is nice because it is proportional to volts. Watts equals volts times amps. This little generator isn’t going to give you enough power to cook or run a refrigerator. But where it will work is if you want to keep a radio or cell phone charged. These are very small consumption devices that run on a 3.8 volt battery using power voltage regulated from a 5 volt input, the voltage of a USB port. A normal phone or handled radio battery is 2600 mAh, or thousandths of an amp per hour. To figure how much consumption the phone draws in relation to the 20 watt output of the K-Tor, we can convert it to watt/hours. This is done by multiplying mAh times voltage, call it five volts, divided by 1,000. So it is 2,600×5/1000, or 13 watt hours. If you pedal the K-Tor for an hour, you’ll get 20 watt/hours. Then take the power consumption ratings for the phone, such as 17hrs. talk time, and you get some actual estimations of how much pedaling you’ll have to do to run simple devices. The circuit in a phone or radio usually only allows the battery to deplete 1/2 way to extend battery life, so factor that in as well. You should be able to recharge a standard phone battery in under an hour of pedaling.
To run a 12 volt lightbulb (you can get 12v bulbs on Ebay and Amazon), usually you’ll be looking at 15 watts or so. So, just like the scene in Soylent Green, you could actually pedal and power a lightbulb. You will probably want to charge batteries instead though, and since the K-Tor supplies DC, you can do this directly.
The product itself has a good deal of plastic, and this is partly because it was really made for backpackers and campers who want to keep their phones charged. Plastic is light, but long term this product will most likely break. I would definitely plan to screw it down to a piece of wood, but you’ll also have to be careful not to twist the unit as you pedal. That would be bad.
Portable power generators, this one and a hand crank device, seems to be all that K-Tor does. They do, however, seem to be successful with the products, which is why we purchased it. Though horribly plastic, the K-Tor is not a bad product. If you can afford it, there are worse investments to keep in your prepping supplies, but it is pricey for a hunk of plastic with a small generator and a couple bicycle cranks. Please see the assembly and use videos below.