I just ran the first full charge-discharge cycle of the latest Yapolamp

 with supercapacitors!

Using the 30F capacitors (marked 44F but Digikey says they're 30F) and the somewhat below-maximum constant current resistor settings, I inserted the PCB USB connector into a 5V USB dumb battery bank. It took a minute or two to get the voltage up to 1.8V and then another 4 minutes to comfortably reach 4.8V. I topped out around 4.9V, which is good to see. The protection diodes were warm, at most.

Then I reset and started the stop watch, hit the button to enter "full on" mode and walked away. Here's a photo from the 30 minute mark: 

The final run time was just over an hour:

62 minutes!

I'm wondering whether smaller capacitors would be more suitable, for a shorter charge-time and run-time. The target user doesn't have much patience for things like charging, so I'm really pleased they take relatively little time to get up to full charge. The next size down is 12F, with a smaller 8mm diameter (as opposed to 12mm for the 30F ones).

Comparing this 1 hour run-time and 4 minute charge timeto the first Yapolamp, powered by the 200mAh lithium pouch cell, it must have been absolutely churning through the Coulombs in a photonically* ineffecient way to discharge itself in the best part of 15 mins!

*made up word, as I couldn't work out the conversion to Arbs.

The PCB is largely updated for the re-spin, with only final checks to go. Code-wise, I would like to try and put a timer on this version, so it warns the user after a period that it's about to enter "always on" from "full on" and then does so, unless it receives a button press to keep it "full on". But in all honesty, it would be fine with the basic button-press to switch between modes.