[Public-list] weight distribution and electric power

[Roger L Kingsland]

Roger,
How DO you recharge your cell phone?

J,

Since I have dropped 4 into the water, most of the time I don't get a chance 
to learn.  Other times I have my teenagers do it.  The are so aggressively 
multitasking, I don't think they notice.

Now I really leave to go rowing.  Must purge the mind with endorphins.

Roger



> Roger,
>
> How DO you recharge your cell phone?
>
> Like you, I can't wait to hear how that electric propulsion system works!
> Pretty jazzed myself...
>
> but not as jazzed as I would be if I knew how to recharge my cell phone!
>
> That is some serious jazz!
>
> Enjoy your row.
>
> J
>
> On 9/29/06, Roger L Kingsland <r.kingsland at ksba.com> wrote:
>>
>> Wow, my head is spinning (more than usual).  With all this technical
>> stuff,
>> I am just happy to know we will soon have an electric powered A30.  Old
>> meets new (well, new to us) and we get to measure the results.  Thanks
>> Dan.
>> I am so jazzed, I feel like finally learning how to recharge my cell
>> phone.
>>
>> Have a great weekend everyone.  I'm off to row on the river.
>>
>>
>> Roger Kingsland
>> Managing Partner
>> KSBA Architects
>> 3441 Butler Street
>> Pittsburgh, PA 15201
>> N40°- 27.83'  W79°- 57.99'
>>
>> (412) 252-1500 x101 office
>> (412) 779-5101 cell
>> (412) 252-1510 fax
>> www.ksba.com
>> ----- Original Message -----
>> From: "isobar" <isobar at bcpl.net>
>> To: "Alberg 30 Public List -- open to all" <public-list at alberg30.org>;
>> "dan
>> walker" <dsailormon at yahoo.com>
>> Sent: Friday, September 29, 2006 3:57 PM
>> Subject: Re: [Public-list] weight distribution and electric power
>>
>>
>> > >===== Original Message From dan walker <dsailormon at yahoo.com> =====
>> >>  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. the owner of the company is an electrical engineer and a 
>> > horrible
>> > salesman. that helped a lot in my decision to give the asmo a try. will
>> > report
>> > in---good or bad when i REALLY know the answers from experience
>> >
>> > =====
>> >
>> > Dan. Maybe the owner is vague not because he's a bad salesman, but
>> because
>> > he's a good one.
>> >
>> > 25 to 50 miles isn't clear unless you know the boat speed. Remember 
>> > that
>> > pre-nuclear submarines could travel  for over a day at 2 knots on
>> battery,
>> > but
>> > only about half an hour at 18 knots. Your range is strictly governed by
>> > motor
>> > current draw at various loads,  and your  engineer/salesman should be
>> able
>> > to
>> > give you a graph of that.
>> >
>> > Take some back of the envelope calculations: How much energy does it
>> take
>> > to
>> > push an Alberg thru the water at 5 knots? Guess 8 HP minimum - think of
>> a
>> > 9.9
>> > HP outboard bolted to the transom. - someplace in that ballpark. That's
>> 6
>> > kilowatts or 6000 watts. With a 48 volt system (same energy as for a 12
>> V
>> > system), that's a 125 amp current draw.
>> >
>> > If your regenerative braking prop gives back 1 amp @ 48 Volts while
>> > dragging
>> > thru the water at an average 4 knot sailing speed (Generous estimate),
>> > then
>> > the 125/1 ratio means you'd have to sail for 125 hours to recharge 1
>> hour
>> > of
>> > motoring.
>> >
>> > If you have a 25 mile range at 5 knots under power, that's 25 miles/ 5
>> mph
>> > = 5
>> > hours X  125 amps = 625 amp-hours worth of battery capacity you'd need
>> on
>> > the
>> > boat. How much does that weigh? I don't know about the capacity of 48V
>> > batteries, but that's the equivalent of  over 25 Deep-discharge 12V
>> > batteries.
>> >
>> > All the above is guesswork, and I could very well be wrong, but you
>> might
>> > ask
>> > the questions.
>> >
>> > Bob Kirk
>> > Isobar #181
>> >
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>>
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