Denny,
It seems like we answer these type of inquiries about every month on this board. It's obvious that most newcomers rarely do a search, because the answer has always benn the same.
Even factoring the the thermal efficiency of internal combustion engines, between 25 and 30% compared to electric motors, about 80%, your calculations stay really bad.
Since most electric conversions can get away with 1/3 less raw horsepower than their IC counterparts, this request is still looking for at least 75hp or more than 56,000 watts. So just one hour could use up to 56 kWh, the request for 3 hours would require more than 150 kWh of usable storage which means closer to 200kWh of batteries. Ignoring how much space would be needed for the batteries, Lithium batteries like mine would weigh 5,000 pounds and cost almost $90,000US. Lead acid would weigh a lttle more than twice that, take up twice as much space but cost closer to $30,000US. These estimates would probably still not deliver the desired performance becaause of the extra weight, so more batteries would be needed, driving up the cost and weight, which impedes performance, requiring more batteries...
So, you're right Denny. There's a reason that there aren't any successful electric ski boats. Sailboats with their intermittant, low power demands can be good candidates for electric conversion. Powerboats with constant high power demands are not.
Fair winds,
Eric
--- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@...> wrote:
>
> 225 hp is 168 kw. Lead acid batteries produce about 20 wh per pound. LiPo maybe half the weight and 5x the price. 3 hours x 168 kw = 500 kwh. That would take 25,000 lbs lead acid batteries costing about $75,000.
>
> Does no one do the math anymore?
>
> ----- Original Message -----
> From: keithchaise
> To: electricboats@yahoogroups.com
> Sent: Saturday, July 10, 2010 10:17 PM
> Subject: [Electric Boats] need feedback re: family boat conversion
>
>
>
> Hello. Just signed up as a new member today. Have question.
>
> I've looked all over the internet over the past week for family IO open bow type conversion to electric but have not found any. I own a 19.5' Crownline, deep V, 3500 lb. boat w/ 4.3 V6 225 HP. I would like to remove the engine, gas tank etc. and replace with simular performing electric drive system connected to the Alpha 1 outdrive. Any one out there done this? What system will give me performance, ability to ski plus about 3-5 hours cruising at a reasonable install cost? I know this is a broad question with tight parameters. I'm hoping to learn from other's experience and knowledge. I can spend $4k-$8k. Help please.
>
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