Author Topic: Electric Drive  (Read 248 times)

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Offline Owly055

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Re: Electric Drive
« Reply #20 on: May 14, 2017, 10:44:48 AM »
220 amp hours is 73.3 amps for 3  hours or 3520 watts.  That's 4.72 HP before the gearbox, probably closer to 4-4.5 HP real world shaft horsepower.    Take your 4 cycle outboard or inboard, and calculate how much power it takes to move the boat at 3.5 kts based on fuel consumption per hour.   1 gallon per  hour is very close to 12 hp.   You should be able to cruise at 3.5 kts on .29 gallons per hour if their numbers are correct.    Typical 4 cycle gas engine efficiency with a fairly efficient engine is .5 pounds of fuel per horsepower hour, and gas weighs 6 pounds per gallon.   Two cycles can burn anything from 50% more upward, often as much as double.  There is no accurate way to calculate horsepower based on fuel consumption on a two cycle, though direct injection engines will tend to burn about 20% more than good 4 cycle... about .6 gallons per hp per hour.  That would be something like the Etech or Optimax.