I was wondering how one could charge a battery as large as the one in the DJI goggles in a reasonable amount of time over a USB connection, but I just noticed that the goggles utilize the QC 2.0 quick charge system which uses up to 12 volts on the line (vs. the usual 5) to allow much more current to be passed when charging. This same system is used on many higher-end cellphones for quick charging and the DJI charger and other QC 2.0/3.0 chargers seem to be compatible. A nice undocumented feature.