When you plug your phone into a power source, there’s no real way to tell how fast or efficient your power source will be. Because of different standards related to high-powered USBs, different systems yield wildly different results: Your decision to charge at your computer could take up to four times longer than using a wall outlet.
The Practical Meter is designed to efficiently display how much power a source is outputting (up to five watts) with a scale that gives a rough idea of how long it would take to charge a phone from zero. The lowest readout, of one watt, is roughly translated to 8 hours of charging time, and the highest indicates a gadget will charge in just 90 minutes. The tiny device, which has already tripled its goal on Kickstarter in the three days that it’s been active, was developed by the same company that successfully funded the thermoelectric PowerPot charger.
The Practical Meter can read the wattage of any USB power source — including outlet converters, solar generators, and car chargers — in real time and connect to any USB-enabled device for charging. Data can transfer seamlessly between a device and a Practical Meter, so users will be able to upload photos or download songs onto phones while monitoring charge times.
The device also shows the disparity between different charging sources. The Kickstarter claims that a traditional PC only outputs 2.5 watts, leading to more than four hours of charging, while a MacBook’s 5-watt USB allows for charging in just over an hour.
The Practical Meter also comes with an optimized 3-in-1 charging connector for iPhone and Android meant to boost the juice to your dead phone or gadget and is available for $20 on the Kickstarter page.