"Cash to throw at a project."
Interesting. I think you are implying that those folks who buy a vendor developed system are throwing money away (not Geo, the OP). I disagree. And here's why...
1. It isn't that much more expensive than what you can buy the parts for yourself, if you duplicate the kit. Maybe 10-15%. They're making their money buying direct and in volume. If you figure all the time you have invested in hunting down the various pieces, and the individual shipping and handling charges, it takes a chunk out of even the 15% "savings."
2. It spreads the R&D cost over multiple folks. Sure, I could have bought a bunch of untested stuff, and then had the fun of trying to make it all work, and realize that I bought the wrong thing, and different parts to match the others. Or I could just get a bunch of stuff I know works together very well, and let someone else absorb the costs of figuring it out. My hobby is sailing the boat, not swapping out motors, controllers, gearboxes, and props.
3. It's supported by a single source. The motor folks can't point the finger at the controller folks who can't point the finger back. I only have to call one number should something go amiss.
4. The purchased drive train parts are only a chunk of what is required for successful conversion. I planned and budgeted my project, then added a good chunk for slippage, and then padded my slipped numbers. I'll be very lucky to hit that target, and will probably have to sacrifice some of my wanted features to do so. I'm still not sure it's fair to toss stuff like a new cutlass bearing into the conversion project, but my wife says that since it's happening at the same time, it's in (same for the bottom job, ouch).
Here is my take on things. A person might think that, for example, the system from Propulsion Marine is expensive; they want something cheaper. There's nothing wrong with buying cheap stuff, if that's your bag. But you really do get what you pay for, and it's all relative. You could get a free motor and controller from a golf cart, some belts and pulleys from an old car, tack together some angle stock, and bolt the whole thing in. It would make your boat go forward and backward. The golf cart parts guy will look at your self assembled PMAC kit and wonder why you wasted so much money when all that free stuff works.
What I see is that the vendors tend to have "higher end" offerings. Double stator motors, Sevcon Gen4 controllers, ClearView displays, etc. It makes me wonder, if the cheaper stuff was just as reliable, with similar performance, why it isn't in the vendor units? Perhaps they've been down that road before (see above comments on R&D)?
Trust me. Even if you buy your primary drive train parts from a vendor, and have him/her help you install and align them, there's still *plenty* of work/ experimenting/ head banging to be done. I spent a couple of hours just this morning creating cardboard templates for the bulkheads I need to make to create a smaller engine compartment and for the controller mounting. I still have to fabricate them, then install them, then glass them. Then the batteries. Then the wiring. Then a bunch more stuff. Then the sailing!
Josh
--- In electricboats@yahoogroups.com, GNHBus@... wrote:
>
> "Cash to THROW at a Project"
> This is a very interesting statement. I see any Project, regardless of
> nature, as cash required, there are costs, no doubt. Some have the ability to
> incorporate "sweat equity" via knowledge & expertise, others must absorb the
> cost of knowledge & expertise. Think in terms of Time. How long & how
> much will you utilize the vessel, how far, and mostly how safe ?
> This really is about the efficiency of moving your vessel in terms of ROI,
> as safely as possible.
> It's a big world out there, I am constantly reminded how the culture in
> good old USA has a major impact on knowledge.
>
>
> In a message dated 3/11/2011 10:23:04 A.M. Eastern Standard Time,
> v_2jgree@... writes:
>
>
>
>
> Hi, Eric, I think you have great points here. Typical ICE setups are not
> a good guide to real needs.
> As a lurking, thinking rather than doing member, I have recently come to
> some conclusions, remembering that my own boat is a cheapie fixxer-upper
> sailboat, so budget is limited:
> 1 - Good tried and tested 'purchasable as a turn-key package' electric
> setups are the way to go if you have the cash to throw at the project,
> as with cars, a new car is up to date, more reliable, and convenient to
> use than most other options.
> 2 - The comparison to ICE is often futile, as ICE setups were probably
> never optimised, other than by sales people at boat manufacturers.
> 3 - The 'green' aspect might not be as high as figured, once the carbon
> footprint of making (consumable) batteries is factored in.
> 4 - It is probably not possible in a practical sense to recharge to any
> large degree from wind or solar if propulsion is used a fair bit.
> 5 - The needs for propelling a (sail)boat other than with sails can
> probably be broken down into two main parts - frequent low power short
> use for docking, and longer term running at higher speeds (hull speed?)
> for convenience and/or safety, such as to beat nightfall, or make port,
> or beat the absence of wind.
>
> The above would seem to indicate that high-ish power is needed to be
> available for long time frames, that is, reasonably long range
> capability at higher speeds. Seeing as the lower power 'docking' setup
> is easy to justify, this means that to get long range and high power, a
> large battery investment is needed every few years, and a larger type
> electric motor also. The logic would seem to be to go with a large
> enough electric drive, but limit the total battery size, and add a
> generator as has been advocated in the past. Good thinking. The snag for
> me is that a large electric motor and controller costs a lot, whereas I
> can nickel and dime smaller ones.
> Putting ethical considerations aside, and using electric if it is your
> own preference for practical reasons (mine is erring towards not wanting
> an Atomic 4 gas engine in the 'living room') then the ideal setup for
> me, as a starting out learner weekend boat guy, would seem to be a
> couple of HP electric as far as motor(s) goes, maybe just 1 or 2 'floor
> cleaner' specification batteries, 12 volt system, and have a gas
> outboard available but hopefully seldom used. The fact remains that
> fossil fuel is very compact, and does not pollute if never used!
> It has been interesting to read about the power and thrust needs. Seems
> that a couple of trolling motors, at 30 lbs or so thrust, would go a
> long way as a starter setup if I wanted a turn-key type deal.
> I can possibly charge for all my needs with wind, maybe a solar panel as
> well (ugly darn oversized things).
> Or, I can haul the batteries out to recharge at home, or even run a
> small generator once in a while.
> I finally got to test out my automotive DC generator idea (actually a
> generator off the Atomic 4 ) and it seems to have no low end torque, I
> can hold it back by hand. It does rev up quite well though. I am going
> to retest with a fully charged battery, but if I get the same poor
> results, then I am thinking multiple electric scooter or robotic motors
> now.
>
> John
>
> 2.2. Re: Thrust to speed numbers
> Posted by: "Eric" _ewdysar@..._ (mailto:ewdysar@...) ewdysar
> Date: Thu Mar 10, 2011 9:35 am ((PST))
>
> GNHBus,
>
> For my conversion I went with a very aggressive 4 blade prop to maximize
> slow speed prop efficiency. Because my prop is in an aperture I
> couldn't increase the diameter significantly. I know that I can
> mitigate the extra drag while sailing by "power-feathering" the prop
> with a little throttle.
>
> But the comment that you made that mentioned hull speed got my
> attention. I don't think that any of the existing conversions spend any
> time at hull speed, the power requirements just aren't worth it. So, my
> drive system can't push my boat to hull speed (about 6.5kts) because I
> would rather optimize the system for the speeds that I actually power
> the boat at, the 3 to 5 knot range.
>
> The recommendations of repowering a boat at 2.5-3hp ICE to 1hp electric
> take this into consideration. Speed is a hp thing and reducing the
> total available hp to 1/3 will probably reduce your top speed. There is
> an assumption in that conversion guideline that the ICE is actually
> over-spec'd and the boat would be just as usable with less hp. With
> ICE, the smaller engine might not have enough torque at slower speeds
> which justifies the larger installation. Electric doesn't have that
> problem, even motors with less hp have enough torque for operation at
> the lower end. So going with only enough hp to get near hull speed is
> generally good enough. The funny thing is that my old Yanmar SVE-12
> diesel couldn't drive the boat to hull speed either.
>
> So it is my opinion that hull speed isn't really important to electric
> conversion because the energy cost is way too high. I can't think of
> any emergency situation that 80-85% of hull speed wouldn't be
> sufficient. And my normal operation is closer is 40-75% of hull speed
> to preserve any semblence of range.
>
> Fair winds,
> Eric
> Marina del Rey, CA
>
> --
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