T-Pain Is On A Boat: Re: [Electric Boats] Any larger electric boat owners out there?

Sunday, May 24, 2009

Re: [Electric Boats] Any larger electric boat owners out there?

100KW to drive it at what speed? Please supply the math your working
in your head.
I would be curious what assumptions your making here.

On May 24, 2009, at 10:16 AM, aweekdaysailor wrote:

>
>
> Denny is being too nice to say it outright, but what you're looking
> for isn't practical today. You'd be needing nearly 100KW continuous
> power to drive that boat -- a minimum of 12 100AH batteries would
> last about 4 minutes. So multiply by 10 -- 120 batteries to get an
> hour of range (Peukert helps here) at 80% depth of discharge. 120
> batteries is ~7000lbs...300 connections to corrode...740 cells to
> inspect...and one bad cell to ruin your day (or hour anyway).
>
> Steyr has some sweet-looking but undoubtedly pricey hybrid diesels
> that might be worth looking at - that would give you a short period
> of "silent running" before needing to power up.
>
> Otherwise - you can "go green" using biodiesel in conventional
> engines. A 30' sailboat is near the practical limit for pure
> electric due to hull form and battery weight factors - that's why
> they tend to be the focus.
>
> -Keith
>
> --- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@...>
> wrote:
> >
> > James,
> >
> > HP is HP, whatever the prime mover. The continuous (not max or
> peak) power rating of your motor is the number to use.
> >
> > The battery bank is the real power constraint anyway, not the
> motor. You want to consider speed and range. Not much sense setting
> up an E boat that will go fast but drain the batteries flat in 5 or
> 10 minutes. Start the design process by defining the speed and range
> you require, select a possible motor/battery system, evaluate cost,
> weight, performance. Repeat until you are confident you have the
> best compromise.
> >
> > Get Dave Gerr's "Propeller Handbook" to figure the prop size and
> rpm best suited to your boat.
> >
> > Google the "Peukert Effect" to see how rapid discharge affects
> battery capacity.
> >
> > You will be removing around 2500 - 3000 lbs from the boat. You new
> installation needs to maintain the original center of gravity or the
> boat won't float level and if it floats bow down maybe hard to steer.
> >
> > Good luck.
> >
> > Denny Wolfe
> > www.wolfEboats.com
> >
> >
> > ----- Original Message -----
> > From: James Sizemore
> > To: electricboats@yahoogroups.com
> > Sent: Sunday, May 24, 2009 3:25 AM
> > Subject: [Electric Boats] Any larger electric boat owners out there?
> >
> >
> >
> >
> >
> > I see a lot of traffic on this list for smaller conversions
> replacing
> > A4's and such on 20-30 foot sail boats. Are there any folks that
> have
> > replaced larger motors on cruisers/trawlers?
> > I will be replacing two 427 fords (350hp gas engines) on a 41 foot
> > Chris-Craft. This if for a number of reasons including not wanting
> > the ongoing expense of buying gas, second I really hate the
> monstrous
> > complexity of combustion engines. I have a computer science/
> > electrical background so I am much much more knowledgeable and
> > comfortable with electrical systems. And not to mention the smell
> and
> > noise of combustion engines. The knowledge I lack right now is boat
> > related: prop size pitch ...etc...etc. I don't need the boat to
> plane
> > at 17 knots or anything like that, although if it does all the
> better.
> >
> > My current thinking is to replace the fords with a pair of (Netgain
> > Warp 11'' or Transwarp 11'')'s. The part I can not rap my head
> > around is if I go direct drive with the Transwarp's will they spin
> the
> > props to fast? Or should I keep the transmissions that the fords are
> > bolt to now and go with the Warp's. I would prefer not to have the
> > extra complexity of the transmissions. The Netgains can move a large
> > truck at freeway speeds 70+ MPH. My understanding of the
> conversion of
> > electrical hp to combustion hp is at 144v these motors should be
> about
> > the equivalent of a 150-200 hp gas motors with considerable more
> > torque at the low end.
> >
> > The boat will soon have a fairly large solar array and already has
> > 7.5 KWH generator. So keeping the battery bank feed should not be a
> > problem. I know finding a solar charger/inverter for a 144v battery
> > pack will be a real challenge. Any recommendations are welcome. I
> > would also be very curious of other conversions of larger plaining
> > hull boats, and what motors you use and performance you get now.
> Also
> > any recommendations on motors/charges/controllers or kits for boats
> > this size would be most welcome.
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>

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