The lightweight and portable Energizer Energi To Go is a nifty device that charges your cell phone from easy-to-find AA batteries. It is compatible with most cell phones on the market and has interchangeable tips to accommodate different cell phone models. Calls can be placed within just 30 seconds of activating the Energizer Energi To Go. So now there’s no excuse to blame missed calls on a dead cell phone. Priced around $20, the reusable charger comes with the phone tip connector and two Energizer AA batteries.