thought both skeptics and bulls of electric propulsion technology might find this interesting.
i recently had an "investment - sailing related" thread in this forum that underwent benign hijacking to an electric boat thread.
wanted to post this following info in relation to that discussion.
recently a 1MWh lithium-ion battery was announced (they stated 1 MW, by which i presume they meant 1 MWh), though not revealed, for an electric boat application.
though likely at this point too heavy for a small boat, if practical, assuming 5 kW (for roughly the equivalent of 10 hp from a diesel, taking into account the differences in power measurement and efficiency for a diesel compared to electric drive as explained in the investment thread) this would result in 1 x 10^6 Wh/5 x 10^3 W = 200 h of motoring compared to, if you took the 56 kWh Li-ion battery out of the Tesla Roadster and put it into a boat, about 11 hours of motoring.
yes its likely far too heavy at this point, but interesting nonetheless.