T-Pain Is On A Boat: Re: [Electric Boats] Electric conversion concepts

Thanks John

My Pearson 26 closely matches your boat and 4 batteries are my intent at 24 volts.

Of all the sailing I've done by myself and on other's boats(Lake Erie Island area), I have seen the most consistant use of motors to first clear the harbor and to return to harbor. The departure and return virtually require the boat to be under full control of the sailor, and although I have seen sailboats enter the channel under sail, I doubt I'd ever take the chance of an errant wind adverselyaffecting my course in tight quarters . . . USE #1.

The second situation I've generally seen auxillary propulsion used, is to return to harbor under a time constraint. Personally, I never understood going anywhere on a sailboat with a time constraint, tight enough to actually have to stop sailing(the reason for going out). Except in dead wind, I've never felt that much better about headway under power as opposed to sail in any but the most dead of winds . . . at which time a couple of knots is fine with me. Pushing wind is a different matter(heading into wind), when trying to make a specific headway which wind just doesn't allow for. Nonetheless, I think back to sailboat races where it's all about making headway on a course as fast as possible. I know sailors in races like speed, but that they are also rather content with far less speed, as long as they're faster than anyone else or are expecting an advantage at the next tack.

So, as I see it, auxillary propulsion to return to port on a time-schedule when one should be enjoying sailing for the sake of sailing is a weak USE #2.

The third use for auxillary power is for safety. Without a sharp eye on the weather and a communications radio, one can forget the timeliness of a fast return to port, when, at best hull-speed will get you there too late anyway. Besides, in the case of weather, a supporting wind will get a boat to and possibly past it's hull-speed much better/efficiently than auxillary power will.

I often read about the need for leeway for approaching storms. I have known some very proficient sailors, but have never met a sailor who doesn't use the auxillary as the first line of defense. I'm less proficient, so it would make more sense to me to accept auxillary as my first line of defense for everything that bothers me or affects my control of my sailboat. Actually, I'm a rather novice sailor, but at that, sometimes I had wished the boat-owner(captain?), would batten down the hatches and give me an education on controlling a boat in a blow. ANYWAY, safety, in my mind is . . . USE #3

There are many other uses for an auxillary motor, but almost every instance is to get from point A to point B. It's never really about getting from A to B with any real degree of speed,even if/when the motor is used, because of the limits of hull-speed and the comparative miniscule size of auxillary motors in the first place, just doesn't allow for "speed" per'se. After all, these are sailboats.

I bought a sailboat in the first place cause I like sailing. I like working with nature to go from point A to point B. The "sail" part of sailing is more exciting to me as the getting from point A to point B. In fact, I get a sort of giddy feeling when there appears to be virtually no wind and I still see a wake behind the boat and I don't like the "change" in tactics when my captain decides to "beat" nature by ignoring the wind(regardless of how feeble the wind might be) and using the auxillary for headway. I dare say, I can feel my societal stress-level rise when that motor is started and my mindset reverts back to the world I try to get away from, when I sail.

Thus, I see auxillary propulsion as nothing more than "auxillary". Not a method of getting from A to B, but rather a way to sorta tidy up the beginning and ending of a sojourn.

I could go on, but it suffices to say that I already hate my auxillary motor. It's being gas, Diesel or electric really doesn't matter as to what it is . . . auxillary is un-natural.

Electric will allow me to be a little more self-suffient than pulling up to a gas-pump or motoring a mile or so to replenish my diesel supply, but of course, I'm probably different on my outlook.

I used to be a naturalist(many years ago) and heavy into wild edibles and self-sufficiency. I look at bicycling in terms of self-sufficiency. I pride myself on using an average of less than 1kw of power a day(a lot of it being used with this computer), and I'm a person who generally cringes at energy-waste. Energy-waste actually bothers me.

So for me, solar panels, wind-power and an underpowered(if needed), auxillary would just in general give a very warm feeling about myself. I even prefer using the panels and not using the "free"(included in dockage), electric at my dock.

Well, I just have to say having a electric auxillary means a lot to me and I'm more than willing to accept the more disconcerning shortcomings of electric propulsion.

It's all about "me".

John Francis Pearson 26

Port Clinton, Ohio

On Sat, Apr 10, 2010 at 8:08 PM, John Raynes <johncraynes@gmail.com> wrote:

Red,

Here is actual running data on my electric boat conversion. The boat is a 26' old Pacemaker and she weighs 5,000 lbs. I re-powered her with a 5KW brushless DC motor and a 3:1 Reducer. The motor runs on two 48 Volt, 100 AH battery packs. I use one battery pack at a time which will give me about 2 hours running time. She will cruise 5 MPH at 50 amps.

John R

Fri, Apr 9, 2010 at 9:15 PM, peoria_diver <daredster@hotmail.com> wrote:

This is right along the lines of what I've been thinking about with solar. Generate as much power as possible with solar panels and wind generators and use the batteries to smooth out the use. That should make the batteries last a lot longer.

From what I've read/heard it takes about 300 watts to move 1000 lbs of boat at 3/4 of hull speed. Triple the watts to run at hull speed. It would be interesting to hear from experienced users to learn if this is a practical figure to make estimates with.

-Red

--- In electricboats@yahoogroups.com, "Roland" <lightdoesnotage@...> wrote:
>
> I too have heard that at speeds less than hull speed that electric is 4 to 6 times more efficient than ICE but that may just be misremembering what I read.
>
> A big advantage of electric is the ability to recharge via wind and solar. It is quite hard to make gasoline on your boat....you need to carry a 50 ton minimum drilling rig, a processing plant (maybe 100 tons?), and then of course you would have to be in a spot that has oil. :-)
>
> But seriously, 2KW of solar would be 12KWH per day minimum in the tropics, which would be like regenerating 1 gallon of gasoline a day for about 300 pounds of panels. If gas is 8 pounds per gallon, then on a 40 day trip the panels win out over the weight of the fuel. At $3 a watt the panels would be pricey, but they do last 25 years...
>
> Instead of thinking about carrying 8 tons of batteries and comparing that to ICE, what about carrying a means of regenerating a smaller bank of batteries, via wind or solar?
>
>
>
> --- In electricboats@yahoogroups.com, John Francis <surv69@> wrote:
> >
> > I'm curious to know if anyone can tell me how much energy(percentage-wise)
> > of top-rated energy(such as optimum RPM's for an IC motor & optimum RPM's
> > for an electric motor), a 26 boat(5000k) running at 1/2 hull speed, would
> > require with a gasoline engine and an electric motor, respectively.
> >
> > I know the answer is dependent on more information, but what I'm trying to
> > compare is if the economy(energy-wise)an electric motor running at much less
> > than hull-speed begins to somewhat approach the economy(energy-wise ) of an
> > IC engine, since the IC engine seems to require much more speed(RPM's) for
> > the same amount of torque of an electric motor.
> >
> > I'm hoping that the electric motor will result in a much lower percentage of
> > the optimum/maximum to go 1/2 hull speed than a gasoline engine would, such
> > that an electric motor at the lower speeds might be 5, 6 or more times more
> > efficient than an IC engine would be.
> >
> >
> > Just curious
> >
> > John Francis
> > Pearson 26
> > Port Clinton, Ohio
> >
> > On Thu, Apr 8, 2010 at 2:35 PM, Eric <ewdysar@> wrote:
> >
> > > Since we typically get new people on the list, I thought that it would be
> > > helpful to post some basic info about electric drive systems that should
> > > help get people's heads wrapped around this technology.
> > >
> > > A quick introduction to electric power concepts and terms:
> > >
> > > Energy is the ability to do work
> > >
> > > Power is the rate at which work is done
> > >
> > > Energy is related to your electricity storage, i.e. batteries. The size of
> > > your energy storage directly relates to your boat's range.
> > >
> > > Power is related your drive system. The rated size of your drive directly
> > > relates to your boat's cruising speed and acceleration under power.
> > >
> > > Energy equivalents: Gasoline contains about 33kWh of energy per gallon.
> > > Diesel is more dense and contains about 38kWh of energy per gallon.
> > >
> > > A 48V battery bank that is rated for 200Ah stores about 10kWh of
> > > electricity. Most comparisons between electric and ICE drive systems figure
> > > that electric drives are 2 to 3 times more efficient than fueled engines.
> > > If one considers electric drive 3 times as efficient, then the battery bank
> > > mentioned above holds energy equal to just less than 1 gallon of gasoline
> > > and only ¾ of a gallon of diesel. This is only true if one is wiling to
> > > drain the battery bank completely, doing so repeatedly reduces the life span
> > > of the batteries. Depending on the battery chemistry, accepted levels for
> > > depth of discharge (DOD) are from 50% to 75% of rated capacities.
> > > Therefore, a typical 48V 200Ah battery bank and electric drive has about
> > > the same usable energy as ½ gallon (2 liters) of gasoline through an ICE
> > > engine. A wet cell or AGM battery bank of this capacity weighs about 500
> > > pounds (225kg).
> > >
> > > Please feel free to correct any misconceptions, or add any additional basic
> > > considerations for those that are thinking about converting to electric
> > > drive.
> > >
> > > Fair winds,
> > > Eric
> > > Marina del Rey
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> >
>