----- Original Message -----From: EricSent: Tuesday, August 03, 2010 9:23 PMSubject: [Electric Boats] Re: hull designIf 1HP = 750W, then 12HP = 9,000 watts. I've been estimating 10kWh/gallon, perhaps that has been too generous, but this might be close enough for our estimations. I've also been using an 80% efficiency for electric drives to allow for other various losses.
Both of these factors should tend my estimates towards the conservative side. But I don't think that many people would be upset if their conversion performed better than they planned. :)
Eric
--- In electricboats@yahoogroups. , "dennis wolfe" <dwolfe@...> wrote:com
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> Per wikipedia http://en.wikipedia.org/wiki/ a modern 4 stroke gasoline engine produces one hp-hour with 0.5 lbs. fuel. That means a gallon of gas (@ 6lb/gal) can produce 12 hp-hr or 16 kWh. Most of the energy in the gas is converted to heat in the engine, not useful work.Brake_specific_ fuel_consumption
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> What is unsaid is that an electric system is around 90% efficient over a wide range of speed while an ICE is quite a bit less efficient running at low load.
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> Denny
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