4KW @ 48v = 100A (minues losses, etc). Looking at the torque curve for say
the Perm 132 @ 48v/100A = 20Nm with a rotational speed of 2203RPM. So, if
you had an ICE with the same output, how fast would your boat go given the
various weather conditions? That's the simple math. IMO, as long as the
electrical system matches the ICE system (or does better) you will have the
same performance with the benefits of using only electric (hopefully) a good
portion of the time - meaning total cost of ownership goes down.
The challenge is the components. How do you get 48v from a generator into
the motor without going through the batteries, and if you did go through the
batteries, how do you prevent overcharging? Then, how do you get a 48v
battery bank to run it when not using the generator and how do you charge
the bank (AC, 48vDC, solar)? All the variables mean more components, which
drives the cost up and makes the system vulnerable to breaking down.
IMO, the ideal system is a 48v bank ~400AHr, 48v DC generator, solar panel
or wind generator inputs and all the components that make it work integrated
into 1 box (possibly liquid cooled). When the bank gets past 50-80%
(depending on battery type), the generator kicks in and does the bulk
charging. The wiring is plug and play and it all fits in a space equal to a
normal ICE engine. I think the electric motor and components have come a
long way towards this goal in the past few years but literally no work has
been done on the generator side.
DaveH
-----Original Message-----
From: electricboats@
On Behalf Of rebollo.angel
Sent: Monday, August 10, 2009 12:30 PM
To: electricboats@
Subject: [Electric Boats] Re: Diesel Generators for electric conversion
Everything said makes sense. However, considering one can get a used
generator and some of them might be in good shape, for 1/3 to 1/2 the cost
of a new one, if I were to do that, would a 4KW suffice for a 48 volt
system? My idea is just to have a back up that the electric motor can run
off if the batteries are all used up.
Thanks!!
Angel A. Rebollo
--- In electricboats@
>
> I concur Dave -- the cost is prohibitive and hard to see how they can
> justify the prices..
>
>
> On Aug 7, 2009, at 2:24 PM, Dave Hackett wrote:
>
> > I've certainly thought of it and do plan to do something along those
> > lines,
> > however I can't understand how they charge $10K+ for an 8KW diesel
> > generator
> > when I can buy a new 30HP pusher diesel for that price. If the
> > generators
> > were in the more reasonable $3-$5K range, I think a lot of us would
> > have
> > been buying them.
> >
> > DaveH
> >
> > -----Original Message-----
> > From: electricboats@
[mailto:electricboats@
> > ]
> > On Behalf Of rebollo.angel
> > Sent: Friday, August 07, 2009 2:35 PM
> > To: electricboats@
> > Subject: [Electric Boats] Re: Diesel Generators for electric
> > conversion
> >
> > I take it nobody has a diesel generator onboard, or have thought about
> > adding one? Any opinions?
> >
> > Thanks!
> >
> > Angel A. Rebollo
> >
> > --- In electricboats@
> > wrote:
> > >
> > > Hello, I have a Catalina 30, and I have been reading the messages
> > from
> > this fantastic group for the past couple of months. I have not
> > decided yet
> > on which electric motor to use, what type of batteries to use, etc...
> > However, I learned about the 1 gallon of fuel rule, and in the
> > interest of
> > safety, I am looking for a genset (we are planning in cruising in the
> > Bahamas next year).
> > >
> > > Right now there are very attractive prices in South Florida for
> > marine
> > gensets, and I am seriously thinking to buy one if I get the right
> > price.
> > Later on, I will get the electric motor and batteries. Given I have
> > a 1989
> > Catalina 30 MKII, 30 feet, what characteristics would you be looking
> > for on
> > a diesel generator? DC only, AC only, DC/AC, 110 & 230 volts, 12
> > volts as
> > well, how many kilowatts, remote start, sound guard, brand, etc... Any
> > advice provided will be welcome. Some models I have seen for sale are
> > Westerbeke 7.6BTD, and Kohler Diesel 3.5 or 4EOZ.
> > >
> > > Best regards,
> > > Angel A. Rebollo
> > >
> >
> > ------------
> >
> > Yahoo! Groups Links
> >
> > No virus found in this incoming message.
> > Checked by AVG - www.avg.com
> > Version: 8.5.392 / Virus Database: 270.13.38/2274 - Release Date:
> > 08/07/09
> > 06:22:00
> >
> >
> >
>
> Lamar Felder
> lamarfelder.
> 713 517 0516
>
>
>
> [Non-text portions of this message have been removed]
>
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