Do your gadgets always lose their charge before you can get to a power outlet? With this new and improved version of our famous 9V USB Charger Kit, you can keep your portables powered on-the-go with cheap, readily-available 9-volt batteries.
Like the original, this kit will let you build a device that provides a powered 5-volt USB port from a standard 9-volt battery. Unlike the original, this version uses a Buck converter that steps down the voltage in a much more consistent and efficient manner. It also uses a custom-printed circuit board for a much simpler assembly.
The 9V USB Charger Kit 2.0 is able to charge almost any device that can be powered by a USB port. The circuit's design allows for it to charge even the most modern portable devices that can otherwise be pretty picky about accepting power. This charger provides 750mA, not 500 or 600 like other chargers, so it can charge power-hungry devices like the iPhone 4 even faster.
Though we haven't tested it with every phone in the world, this charger kit is confirmed to work with all current-generation phones, including the iPhone 4. It will also work with any iPod MP3 player capable of charging via USB.Click here for a list of all devices with confirmed compatibility.
While still a great solution, the original 9V USB Charger Kit's voltage-regulator-based circuit is about 65% efficient. That means 65% of the power from the battery makes its way to the USB port, and eventually the device you wish to charge. Inspired by the original Electroids kit, other kit designs such as the MintyBoost attempt to solve this efficiency problem by using two AA batteries, totaling 3 volts, and stepping the voltage up to 5V. The result is a charging kit with about 80-85% efficiency
We think we've done one better with the Electroids 9V USB Charger Kit 2.0. It still uses a 9-volt battery, but instead of a traditional voltage regulator which bleeds the extra 4 volts off as heat, it uses a Buck converter, an integrated circuit that redirects the excess voltage to a capacitor until it can be used. Because almost no electricity is wasted, the result is a USB charger that is around 95% efficient, or 10-15% more efficient than the MintyBoost and 30% more efficient than the original 9V USB Charger Kit.