MPPT

In 2010 Sh3d designed a tiny MPPT to charge lithium-ion batteries from solar panels mounted on wave buoys deployed in very cold conditions. Battery management included temperature control and MPPT across multiple panels facing different directions (due to the physical design of the buoy).

Lithium batteries don’t handle low temperatures well — non-rechargeable alkaline cells are the best choice for extreme cold. Combining MPPT, careful battery and temperature monitoring, and fall-back alkaline cells, the buoys ran for many months even with rechargeable Li-ion packs.