i'm new to this list and electric boats, but intrigued. Makes
sense, and great simple explanation. But I am wondering how they
are getting 2000# plus elec cars to move at 70mph, and without 100-200
batteries? Can't that tech be used in boats? Yes, drag of water is
worse than tires on pavement, but is it THAT much difference to cause
such a big drop in MPH? I guess a lot is lost with the nature of a
prop as well vs 4 rubber tires on pavement. But maybe the motors
they are using in these elec cars would be stronger and more efficient
as I/O's in boats - vs elec outboards? I'm sure there's lots of
considerations I'm missing.
On Oct 9, 2010, at 7:24 PM, dennis wolfe wrote:
>
>
> I wouldn't do it. A deep V hull is designed to go fast (with a lot
> of HP) and ride relatively smoothly over waves. Your boat has 165
> hp and the engine, I/O and a full tank of gas weigh less than
> 1000#. It can probably run a couple of hours at wide open throttle,
> maybe 40 mph. The total boat weight is around 2000#.
>
> 165 hp = 120 kW, this much power for 2 hours = 240 kWh. A 60# lead
> battery holds 1.3 kW and costs $100 to $250. For equal power you
> would need 185 of these batteries; over 5 tons and $20,000! This is
> why there are no practical electric speed boats.
>
> If you had around $5000 to spend on an electric drive system,
> including batteries, you would want a displacement hull, like a sail
> boat, around 18 to 24 feel long. You would be able to cruise around
> at 5-6 mph for 5-7 hours on a charge. If that is the kind of
> boating you want to do electric would be a good choice. There is no
> substitute for the magic of moving along in near silence but you pay
> a steep price in speed and range potential.
>
> Denny
>
> ----- Original Message -----
> From: Stef Mob.
> To: electricboats@yahoogroups.com
> Sent: Saturday, October 09, 2010 5:26 PM
> Subject: Re: [Electric Boats] Want to convert a glasstron 184 to
> electric. Any advice?
>
>
>
> So, in short words: don't do it?
>
> Is there a equation point? In other words: with a dc motor of xxx
> hp, it Will be great?
> Or do i just need to look for an other (type of) boat.
> I thought a V-hull would be great? ( as they make a speed boat of
> it...?)
>
> How can i compare gas and electric motor power with eachother?
>
> Thanks.
>
>
> Op 9 okt 2010 om 22:49 heeft "dennis wolfe" <dwolfe@dropsheet.com>
> het volgende geschreven:\
>
>>
>>
>> First do this thought experiment: Take out the old motor (500#?),
>> add 1200 lbs batteries. Now clamp a 10 Hp outboard on. Put on
>> really good ear plugs. At WOT you would get maybe 6-7 mph for 60
>> - 90 minutes. Maybe 4x run time at 4-5 mph. That's what your
>> electric boat will be like. If that seems good to you go ahead.
>> You are looking at several thousand dollars for a motor and
>> controller that big. You would need a hefty charger too.
>>
>> Old deep V fiberglass hulls are a dime a dozen but are the worst
>> possible hull form for efficient electric power. A boat shaped
>> like a big canoe (think old sail boat sans keel) is the best design
>> for easy propulsion.
>>
>> Denny
>>
>> ----- Original Message -----
>> From: stef
>> To: electricboats@yahoogroups.com
>> Cc: stefwesbeek@tiscali.nl
>> Sent: Saturday, October 09, 2010 6:22 AM
>> Subject: [Electric Boats] Want to convert a glasstron 184 to
>> electric. Any advice?
>>
>>
>> Hello,
>> I've been leeching the group for a few months now, and became
>> enthousiast in electric boating.
>> Currently have a inflatable with an little outboard electric, and i
>> really love the silence, and the ease of boating. (never expected
>> that..)
>>
>> Now, i can get 32 batteries AGM 12V 80Ah for free from a relative
>> (4 years old, come from a no-break system), so i want to convert a
>> boat to electric.
>> Currently, i found a Glasstron 184 with a broken engine, but in
>> exellent shape, and overhauled tailpiece.
>>
>> Can anyone give me advice about motorising this speedboat?
>> I was leaning towards a 10 to 20Hp series wound dc at 96 volts,
>> with 3 battery banks in parallel, giving me 96V and 240Ah.
>>
>> Any ideas, or recommendations, before i actually purchase the boat?
>>
>> Biggest question is if the hull of the boat is capable of being
>> thrusted by electric, instead of the original 165Hp six cilinder
>> inline...
>>
>> Many thanks!
>>
>>
>
>
>
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