PCBs arrived a while ago, nice and crisp.
Since debugging the Heartbeat Logger proved harder than thought, I took the time to solder up the Lys Bright board (who could retain themselves anyways?), and then butchered it a bit to measure the current through the LEDs. I preferred the 15cm JST SM connectors a lot over having 2mm JST connectors onboard, as these are seven times easier connecting and disconnecting from the battery and the solar panel.
Well, did it work? A little yes, mostly no. It turns out you should do at least some basic maths on boost converters before you slap them onto the board, not just examine the datasheet and stick your finger in the air ;)
I used a single li-ion battery on this and had four 350mA LEDs in series. Max allowed switch current of the LED driver was 650mA. Wanna guess why this didn't work? :)