[Public-list] weight distribution and electric power

[John Boor]

If regenerative braking is considered the prop would have to be replaced
with a 3 blade since the standard 2 blade would align with the keel and
provide no rotation.  Even a 3 blade would produce drag and I am not sure
how much torque would be needed to generate power.

John Boor
MAHSEER #380

> I have no idea how Dan is planning to recharge while sailing, but solar
> panels are not the only way to do this. 2 other examples are wind
> generation
> and water turbine generation.
>
> Water turbine generation was used by Gelinas during his round the world
> cruise. It basically uses a propeller as a turbine, connected to a shaft
> which drives a generator. Since a motor and a generator are physically the
> same thing, most electric motors can be used as generators, and in fact,
> most electric launches are set up in exactly this way.
>
> Regenerative braking in hybrid cars works exactly the same way. This
> technology is well established and frankly much older and more mature than
> photovoltaic solar power.
>
> I don't know much about efficiency numbers, but if Dan figures he's
> motoring
> for 15 minutes to a half hour to get out of the harbor, followed by
> several
> hours of sailing, I am guessing that since the generator is running at
> least
> 10 times longer than the motor (assuming 2.5 hours of sailing for every 15
> minutes of motoring), he probably is not going to have a problem replacing
> whatever juice he took out.
>
> Plus he'll have a sweet way to recharge his house batteries and replace
> the
> juice taken out by his lights and refrigeration and electronics and
> whatever
> else.
>
> I wouldn't use the system while racing, though...that pesky 2nd law...no
> free lunches and all that.
>
> JB
>
> On 9/29/06, John Boor <mahseer at kos.net> wrote:
>>
>> > yes john, no gasoline.
>> >   i was told i can motor 25 to 50 mile before empty. supposedly th
>> batts
>> > will recharge as i sail. the system has "smart" chargers that i am to
>> > plug in while at the dock. i wont know until next springs sea trials
>> how
>> > well any of this works.
>>
>> Dan
>>
>> I am looking in to solar panels to recharge my house batteries(4x 225Ahr
>> 6volt batteries) my concern is that 2 80watt panels at about 30x48in
>> each
>> will just keep my batteries charged when I use my refridgeration
>> (2.5Amps
>> per hour) this is with full sun (no shadows on the panels)all day. With
>> your 48 volt system and limited sun hours I cannot see your bateries
>> beind
>> charged very much while sailing. I hope you have resolved this problem.
>>
>> John Boor
>> MAHSEER #380
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