How many people will it take to power my laptop and projector, or pedalboard (or any device)?
Pamela Parker’s pedal board at the Peace Day SF rally. Photo: Nio.
Okay, so you have a device or set of devices in mind (like a laptop and projector), and you want to know whether it’s possible to power them with people on bike generators. Here are the steps to figure it out:
First, you need to measure the power consumption of the device you want to power. There are two ways to do this. You can read the writing on the product or you can actually measure it using a device like the Kill a Watt. The second way is better for two reasons: It’s more educational and fun, and more precise; some product ratings (written on the product) are just approximate. Some products use different amounts of power at different settings. For example, a loudspeaker will use way less power than it’s rated for if you’re listening to music at moderate levels. So get yourself a Kill a Watt and get scientific!
Above: A Kill a Watt in use.
Connect the Kill a Watt to the wall, then connect your device(s) to it, and read the wattage number. (Be sure you’re in watt mode; the device may default to showing volts. If the reading is very close to 110, USA AC power voltage, then you are probably reading volts.) If you look carefully you’ll see that the watt mode will have the unit “watt” next to the reading.
Next, visualize what types of pedalers you are expecting at your event. The wattage you can expect per person will change depending on who is pedaling. This is common sense: A competitive cyclist can generate more power than a 3rd grader.
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