Some details and pictures from when the boat was at the Miami Boat Show:
We had a number of different battery configurations that we tested to try and find the right balance of capacity and weight.
To get the batteries to charge that fast, the sunpads on the deck unfolded to expose more solar panels, and some dual surface panels were used that had higher output. We also had the batteries in banks that we could selectively charge (or discharge) them based on the power available
The goal was to have enough solar and batteries on board to be able to live on it, and not have to have a generator. Battery capacity was initially based on runtime targets, but was ultimately reduced to match the electrical demands of the boat while in "house mode"
The "hey we can have a smaller engine and help out with electrical power to get on plane" stuff came later.
Fun memory: I got (had) to test the GFI system we made, it blew some pyrofuses that disconnected the batteries in case something went wrong. It was a little unnerving to touch 700VDC, I used successively smaller resistors to be safe, but in the end did touch the bare battery cable, then did it again while the motors were under full load, and again under full regen:)
Working on boats sucks enough as it is, having to wear full PPE (personal protective equipment) in Florida while in the bilge gets old pretty fast!