General use fuel cells (Score 1)

Does anyone know the practicallities of replacing normal lead acid batteries charged by a generator (on a boat) with methanol fuel cells. The batteries are used for domestic power and charged by generator/engine/wind/solar (in that order) on a sail boat. If I could use silent efficient fuel calls instead (prolly keap one lead acid for engine starting curent and store the solar/wind that I have anyway) and save the wieght space of the genny I would be a happy hamster. Thanks for help :) one Calm Whore