1. The problem statement, all variables and given/known data Req'd to calculate power avail for propulsion. Given 2x 475kW fuel cells, 6400 kWh lead-acid battery. Ships machinery power requirement is 1100 kW at any given time, and battery max discharge rate is 1.2 kW/kWh. 2. Relevant equations I'm not sure I fully understand the how all the units fit together to determine what power if left over for propulsion given the battery discharge rate, and the consumption of 1100 kW. It obviously would have to be a positive value. The kW and kWh units is what seems to be confusing me. 3. The attempt at a solution 475kW x2 = 950 kW avail from fuel cells, subtract the 1100 kW consumption load = -150 kW. ? How does the battery add to that?