MPPT (maximum power point tracking) charge controller for the solar input that keeps the battery pack alive between sunny windows.
Why we designed our own
At the small battery sizes used in solar WII buoys, no off-the-shelf MPPT existed that was a good fit — commercial MPPT controllers were designed back then for vehicle, off-grid, or marine packs at least an order of magnitude larger than what a buoy carries. The available options were either too lossy at low currents, drew too much quiescent power, or had input/output ranges that didn’t match a small solar panel + lithium-pack combination.
So we built our own. The result is an MPPT optimised for:
- Small battery capacity — sized for the buoy pack, not a vehicle.
- Low quiescent draw — the controller itself can’t be a meaningful fraction of the buoy’s deep-sleep current budget.
- Small panel — input range matches the panels we can fit on a buoy enclosure top, with anti-slide spikes and antenna clearance around them.
- Cold operation — has to keep working at the Antarctic temperature range, where commercial controllers often spec out.
Status: placeholder. Schematic, board layout, efficiency curves, and deep-sleep current measurements to follow.