According to the Power Transfer Protocol documentation ( https://developer.motorola.com/explore/firmware/power-transfer ), there are four defined power sources as enumerated by ptp_power_source: PTP_POWER_SOURCE_NONE, PTP_POWER_SOURCE_BATTERY, PTP_POWER_SOURCE_WIRED, and PTP_POWER_SOURCE_WIRELESS. Which one would a solar power mod fall under? I can understand that if the mod contained a battery in conjunction with the PV panel, it would probably be classified as just PTP_POWER_SOURCE_BATTERY. But what if it doesn't contain a battery? Would it be PTP_POWER_SOURCE_WIRED or PTP_POWER_SOURCE_WIRELESS? And what are the min/max electrical specifications for each power source?