Energy & Sustainability Technology

Over at the Maui Makers hackerspace, member Ryan K showed up with a mess of Lilikoi fruit (also known as passion fruit). Using anodized bolts (source of zinc), some thin copper pipe, wire, switches, LEDs, and a capacitor, he built himself a battery from the fruit.

The Lilikoi vine produces a massive amount of fruit in Hawaii, often creating a nuisance for home-owners who own a plant. The fruit drop and have to be cleaned up, otherwise they rot and attract insects. Ryan tasted one and noticed it was quite acidic and might be a good candidate for a homemade battery.

The fruit charge a 6800 uf capacitor, and when the volt meter hits 3v, the switch can be thrown, letting the green laser emit a short pulse. For those curious, two days later the charge was down to 1.8v. Obviously this is a supply and demand issue they’ll need to sort out.


In addition to being an online editor for MAKE Magazine, Michael Colombo works in fabrication, electronics, sound design, music production and performance (Yes. All that.) In the past he has also been a childrens' educator and entertainer, and holds a Masters degree from NYU's Interactive Telecommunications Program.

View more articles by Michael Colombo