Wait for the amber solid light to turn on, indicating it has external power
Allow a complete boot to occur
Press left until you arrive at Settings
Go to BackLight Brightness
Press left all the way until the screen goes completely dark
Allow a 30-60 minute charge to replenish the battery
Press right a few notches to access a desired brightness level
Note: This will help you get your system charged faster than normal. If you want a precise numerical percentage of what your battery energy is at, go to Utils and choose Bean.
Server mode would be even better, if you needed to have SSH access, since the backlight time out is much lower. But I’m guessing you mean having faster charging while still being able to use it.
Also, just letting it auto shut off, say if you’re using balanced or power saved mode still lets the unit charge.