48 Hour Rechargeable Night Light

A couple days into our trip I had free time and finished assembling everything into the case and started runtime test.
Observations:

• Form factor is a little weird due to the cell shape & size.
• Brightness is plenty to see by in the dark - brighter than I'd like actually, I ended up putting it under the table pointed at the wall.
• Not quite as bright as a flashlight though

After 72 hours of continuous run I went back to check my math. It turns out I mis-read/mis-remembered the cell capacity and it's 13.3Wh, not 3.7Wh, which means I should have about nine days of runtime with the current ~17mA configuration. I guess it meets original design requirements. 

Future thoughts:

• Multiple brightness modes could be useful, at least for nightlight/working light levels
• It needs better physical design for light modes
  • Nightlight - anti-glare/down-light
  • Table/general - diffusion, also anti-glare
  • Flashlight - no diffusion, able to pick up and hold directionally

I'm not sure if all of those can be done well at the same time or not but it's percolating.

Parts were collected, and bodged together. I did this all the week before going camping for a week - I figured that would be a good test.

Initial math told me with a 3.7Wh cell I should get 48hr runtime if I use less than 20mA, so I used a 220ohm resistor. This gives ~17ma at 3.7V nominal for the cell.

I whipped up a quick 3d printed clamshell prototype, charged it up, and went on vacation.