Thanks for the numbers James. I assume that 3KW @ 5.75MPH is measured performance from your Catalina, right? Sounds reasonable.
Just for grins, I'll throw out some rough numbers for a 48V battery-electric setup with a brand-new outboard for backup.
Drive unit: $4,000
Batteries (8 ea. T-105)$1,200
15A, 48V charger $ 300
15HP 4-stroke outboard $3,500
Outboard bracket $ 500
Total: $9,500
Weights:
8ea. batteries @ 62 lb 496 lb (from Trojan literature)
drive unit and cables 125 lb (guess)
charger 25 lb (guess)
outboard and bracket 130 lb (approx)
gas for 50+ miles 40 lb (approx)
Total: 816 lb
The Trojan T105s are rated for 115 minutes at 75A, so lets say an easy 2 hours at 3000W (62A). That'll give you 10 miles at 5 KT.
If you go to a 72V system (4 more batteries), the range should about double.
Not sure what my point is, but it's an interesting comparison.
Cheers,
Jim
--- In electricboats@
>
> A Catalina 30 consumes 3 KW at 5.75 miles per hour continuous,
> provided the bottom is clean and there are no obstructive though hulls.
>
> It takes 8.7 hours to motor 50 miles at this speed.
>
> it takes about (3 x 8.7) 26 KWH to motor 50 miles. However,
> there are probably going to be wind and waves along the passage, so
> add another 20 percent for weather.
>
> It will most likely take 32 KWH to run 50 miles.
>
> A 2 panel solar array constantly aimed at the sun may produce 420
> watts for 8 hour on the longest day or 3.3 KWH.
>
> this leaves battery capacity required at 28.7 KWH.
>
> Lithium Iron Phospate battery packs by Thundersky are rated at 160
> amp hours @ 48 volts = 7.6 KWH of which 80 percent is useable or 6.1
> KWH. A 48 volt pack of these batteries costs around $3,000. You
> would need 5 packs which would yield 30.4 KWH.
>
> Each one of these battery packs weighs 200 lbs, so total weight would
> be 1,000 lbs, still less than the AGM pack I have on my Catalina 30,
> Kapowai.
>
> You could install the batteries under the aft bunk, under the
> starboard settee and next to the engine, and if necessary under the
> front bunk.
>
> Approximate price of all components would be
>
> Drive Unit: $5,000
> Batteries: $15,000
> Battery Chargers: $3,000
> Cables etc. $1,000
>
> Estimated Total: $24,000 plus installation and options.
>
>
>
>
> James Lambden
> Propulsion Marine
> 805 455 8444
>
> www.propulsionmarin
>
>
>
>
> On Mar 22, 2010, at 4:58 PM, MarkH wrote:
>
> > Hello to all. I bought a Catalina 30 3 years ago, (30 foot sloop
> > sailboat, 10,500lbs). It's a 1986 model with a 21hp 3 cylinder diesel.
> >
> > Ironically, I'm not having any problems right now. However, a
> > diesel is noisy, smelly, requires constant maintenance of filter
> > replacement, oil changes, fuel, etc… You guys know this, I'm
> > preaching to the choir.
> >
> > Electric propulsion is an attractive option for me; but I do have
> > some concerns.
> >
> > 1) I know electric propulsion will work for 90% of my sailing; 15
> > minutes out, an hour or three later, 15 minutes of motoring back to
> > the dock.
> >
> > 2) BUT, my concern is how this will work when I cruise up the canal
> > from Elizabeth City North Carolina to Portsmouth Virginia, a 50
> > mile, 8 to 10 hour journey … can I do this with electric
> > propulsion?? This trip cannot be done at a slow 3 knots or less to
> > conserve amps; one must keep up 5 knots or so, to make the lock
> > schedule, and to keep out of others way coming up behind you in the
> > relatively narrow canal.
> >
> > In other words, can one feed charging juice to the batteries with
> > either solar, wind, and/or generator while still moving at 5 knots,
> > without stopping to recharge, making it possible to make a 50 mile
> > trip at full speed non-stop?
> >
> > The title about being crazy … fellow members of my yacht club think
> > I'm from Mars when I suggest converting to electric. This may
> > simply be I'm a reader and keep up a bit more with current events
> > than many others; although this topic isn't exactly current events
> > since electric powered sailboats have been around for many years.
> >
> > I also realize new lithium-ion battery technology may change the
> > formula significantly in the near future … that's what I'm hoping
> > for anyway.
> >
> > BTW … anyone want to take a stab at what a 25 year old, 21hp 3
> > cylinder, model M25 Universal diesel in working condition, worth?.
> > The exact hours unknown. It was showing 1,000 hours when purchased,
> > but the hour meter wasn't working at that time.
> >
> >
>
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