Originally Posted by geekmaster
The kindles also use even higher voltages internally, such as the high-voltage waveform used to electrostatically control the eink display. The battery is not the highest voltage (even for the LEDs).
Oh thank you for that. I found the waveforms yesterday on the Kindle and (wrongly) assumed they have something to do with the LEDs. Maybe some magic that is calibrated towards each individual PW so that all 4 LEDs output creates the desired effect. Learn something every day.