John, Great rant. You nail the cultural bias of Western Societies: dominating power vs accommodating environment. This myopic proclivity has advanced the whole world with fantastic alacrity, but now threatens our survival as a species. Will we be able to put down the crack pipe and live in complex relationship with our environment? Or will we use a bigger throttle, bigger gun, bigger wallet, to assert our self-centered ego? Stay tuned!
Mark Stafford
--- In electricboats@yahoogroups.com, John Francis <surv69@...> wrote:
>
> WOW!
>
> We are talking about sailboats . . . aren't we?
>
> Personally, I don't know why anyone would even consider $5000+ to put an
> electric motor in a sailboat and still have to concern themselves with
> whether or not it might not be enough engine for the boat.
>
> I have a 70-pound thrust motor on my 28' Newport . . . adequate propulsion
> for a boat that generally doesn't need an engine. Years ago(about 15), I
> adequately operated my MacGregor 25 with a 37-pound thrust motor.
>
> I have made many, many thousand mile trips on a 250cc Yamaha. My 400cc
> Yamaha was always more than enough engine to make trips. BUT still
> virually E-V-E-R-Y-O-N-E claims that 1100cc is the absolute minimum engine
> needed and a lot of posters on the internet say something around 1500cc.
> Even if a discussion includes a utilizing a 650cc motorcycle, it seems
> everyone jumps in to virtually berate the very idea of using 650cc for
> trips.
>
> Why is everyone so doggone power crazy . . . especially in an endeavor
> that's not about "*POWER*", such as sailing.
>
> Seriously . . . this leads me to wonder if this is a real discussion about
> green energy, which generally requires some degree of compromise(on the
> side of conservation), on the part of participants, or is this really just
> another conversation of one-upmanship and full-speed ahead in what's new
> for the moment?
>
> If everyone so desperately needs the speed and power they've always enjoyed
> in the past(and over utilized), then why not just keep the old boiler-plate
> engines in place, keep the speed as high as possible and leave the smell
> behind . . . in your oily wake.
>
>
> argh
>
> On Fri, Nov 16, 2012 at 7:48 AM, Arby Bernt <arbybernt@...> wrote:
>
> >
> >
> > Yes.
> > Running at wot (wide open throttle) will require a generator and power
> > converters rated appropriately. WFCO makes 35amp units that have a foldback
> > voltage feature. You pull more than the rated capacity, and their output
> > voltage will decrease proportional the the load, until the converter shuts
> > down.
> > If you're running a Honda "2kw" genny, it can maintain a continuous
> > output of 1.8kw (reference from memory) continuously. This means you can
> > run your system at PARTIAL throttle only, basically drawing 1.8kw max. Buy
> > a set of 95a WFCO converters, and a much larger genny, or two paralleled
> > smaller ones, and you'll be able to run more power.
> > Be careful, however. Running any system at 100% capacity is a fool's
> > errand. Build headroom into your design, and plan on over-spec'ing your
> > components. I use Kelly controllers turned down to 60%, for example, to
> > build a more stable product. Yes, you can pull 35a out of a unit rated as
> > such, but why push the limits. You don't shift your car at redline, so why
> > treat your boat motor system any differently?
> > Sailboats can motor at low speed very efficiently. if you plan on extended
> > motoring, get a generator at least 20% larger than required by the power
> > converters. Size the converters at least 20% over your motor load.
> >
> > Be Well,
> > Arby
> >
> > On Nov 15, 2012, at 11:05 PM, "kotyara73" <krollokot@...> wrote:
> >
> >
> >
> > Wouldn't 35amps x 4 overload the Honda? if the batteries are drawing all
> > they can, that wouldn't leave much room for the motor. Or am I
> > misunderstanding all this?
> >
> > --- In electricboats@yahoogroups.com, Arby Bernt <arbybernt@> wrote:
> > >
> > > Go with the WFCO units. Each unit tends a single battery, 35a continuous
> > output with three stage charging. Dozens installed, not a single failure
> > (except one installed in reverse polarity, don't go there...)
> > >
> > > Be Well,
> > > Arby
> > >
> > > On Nov 15, 2012, at 8:28 PM, "kotyara73" <krollokot@> wrote:
> > >
> > > > One thing that I never really gave much thought to is the battery
> > charger. But now, having read the recent discussions on the topic, I
> > started doing some more research on it and now I more confused than ever.
> > So, I'd like some help choosing the right unit. Battery bank will likely be
> > 4x100-150Ah AGMs feeding ME907/Sevcon kit. Here're the requirements (or at
> > least draft requirements :)
> > > >
> > > > 1. Has to be able to work with the Honda genny. I gather that means
> > drawing between 13.5 and 14 amps from it, which should result in ~25amp on
> > DC side.
> > > >
> > > > 2. Has to be able to supply that power to the motor when the batteries
> > are low. Otherwise, what's the point of a backup genny?
> > > >
> > > > 3. 4-bank 12v charger so as not to worry about battery imbalance? Not
> > too sure about this one, but it seems reasonable.
> > > >
> > > > 4. Has to be robust enough to be left plugged in for a couple of weeks
> > and keep the batteries happy. There won't be any other load at this time.
> > > >
> > > > 5. Solid state rather than transformer, for efficiency.
> > > >
> > > > 6. Not too expensive. I'm figuring $500 tops, but obviously the lower
> > the better.
> > > >
> > > > Here're the options that I've gleaned from discussions in this group:
> > > >
> > > > 1. Elcon. Sounds like the right unit (except for being serial), but
> > it's $750...
> > > >
> > > > 2. QuickCharge. Transformer, doesn't sound very robust.
> > > >
> > > > 3. DualPro. Issues with motor load while charging.
> > > >
> > > > 4. Zhivan. Not sure what to think of this one.
> > > >
> > > > 5. ProMariner. Saw it mentioned once. Sounds good, but I can't figure
> > out their specs. When they say it's 4-bank 60Amps 12/24/36/48, what exactly
> > do the amps refer to? They don't list their input amp draw either.
> > > >
> > > > 6. 4xWFCO converters. Arby's special :) Seems like a good solution,
> > but single unit would be nicer. They also sell main boards, would it be
> > difficult to put four of them in a single enclosure?
> > > >
> > > > So, as I said, I'm confused. What say you? What would be the best
> > option?
> > > >
> > > >
> > >
> >
> >
> >
> >
>
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