How-To: Build a battery-free flashlight

How-To: Build a battery-free flashlight


Mr. Rigsby shares his design for an LED flashlight using two 220 farad(!) capacitors in place of all-too-familiar disposable batteries –

In this project, you will make a flashlight that works without batteries. Even more amazing, you can recharge it in three minutes and it will run for more than 24 hours. Because the ultra capacitors can be recharged thousands of times, you may save the environment from ever receiving an old flashlight in the trash system.

Very cool. It’s worth mentioning that the lengthy operating time from one charge wouldn’t provide constant illumination. In the Instructable’s comments, the author notes that after 2-3 hours the LED’s brightness would drop to “night light” levels. Others point out that this could be remedied to some extent by using a driver circuit to keep voltage levels up. Still, imagine fully charging a portable device in about 3 minutes – I smell future!

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