Love the longboard shape sitting on the back of the battery! Great work…
I’ve been through the rechargeable batteries paths and the self-discharge, especially when temperature varies, is frustrating. I also tried primary non-rechargeable cells, but they’re very, very expensive and need some complicated energy buffering as they cannot deliver more than a 2-5 mA continually (otherwise you cause damage to the cell).
I’ve been experiencing with low-power for while and at the moment having some success with Whisper Nodes and 2xAA. Alkalines are to be cheap and reliable… saying that, I’m really keen to reduce the size of one of my nodes and I’m trying to work with solar harvesting + super-caps (or tiny Li-Po). Found a TI and an ST solar harvesting ICs, just trying it out to see how small can I go with the solar panel. My idea is to transmit every 1h-6h, will post something if I get things to work.