Can't easily charge from a 200mA USB port

[ali1234]

Many USB ports are limited to 200mA. One example of this is the ports on the RPi keyboard. This is about 50mA less than the blit needs when the backlight is at maximum. The "power off" option has no effect when connected to USB power, so in order to charge the blit on such a USB port, you have to manually turn the backlight right down to reduce power consumption. Otherwise the battery will slowly discharge instead of charging.

Assuming that there is a hardware reason why "power off" doesn't work on USB power, this could be mitigated by adding a "sleep" mode to the launcher. If no button has been pressed for 1 minute, dim the backlight.