[Public-list] weight distribution and electric power

[J Bergquist]

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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