Last year Kyocera showcased a rugged smartphone with solar charging built into it at MWC. This year Kyocera is expanding on that idea, with its new prototype that is running a forked version of Android. According to partner Sunpartner Technologies, Kyocera's new prototype is all about efficiency. Three minutes of charge time gets one minute of talk time, whereas the model showcased last year required 10 minutes of charging for two minutes of voice. Kyocera didn't reveal any pricing or availability for the prototype.