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Old 29-07-2014, 18:34   #31
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Electrical Conversion

Think of an electric boat being almost what you have except limit yourself to half throttle and you have a 1 gl fuel tank, and it takes overnight to refuel that tank too.


If you can live with that, and I think a lot of daysailors can, then electric conversions are viable.
With the conversion loses mechanical motion to electrical generation 110V to 14V or so, electrical to chemical conversion, chemical back to electrical, and electrical back to mechanical a Genset isn't a very efficient way to power a boat.
Little Honda 100% duty cycle is 1300 watts I think? 1300 watts is roughly 2 hp? with losses you have less than 2 hp to drive the boat, plus the little Honda screaming away?

Electric conversions for anything other than day sailing, amy not make much sense? Their primary use is more of a novelty than a practicable solution?

On edit, 18 batteries may not be much if any heavier than a little Diesel and the systems that go along with it?
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Old 29-07-2014, 18:39   #32
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Re: Electrical Conversion

Honda is 1600 W, where did 1300 come from? Still less than 3 HP, I think
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Old 29-07-2014, 18:45   #33
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Re: Electrical Conversion

a64-
I'm not talking about posterity, but the guy's in college. Which almost always means that in three more years, max, he'll have some radical life changes coming up. Probably moving, probably changing priorities, and a very good chance that the boat becomes the wrong boat for him for any number of reasons. Either way, it would be nice to have some resale value in the boat, rather than none.
A generic 20-odd footer can always be sold for something, but once you tag on the "homebuilt/homepowered" tag, that's gonna complicate life.

I've learned that there's usually a reason for "conventional" and learned a long time ago that the best way to break the rules, is first to know them all. Which would mean, learning up about electric propulsion systems, working out battery capacity issues, hp issues, etc., and only then looking at whether it was suitable for the boat. If the boat was built with an 18(?) hp engine and you install a 4hp engine...folks are going to tend to make a face and walk away. Maybe not all of them. Hey, I've seen a lot of cars custom-painted a gawdawful color, even one with magenta headlights (!) that someone dearly loved.

But, you know, it's just a boat. Outboards you can buy and sell and easily undo a mistake with. Used engines, ditto. But a custom one-off conversion? In two fields (electric propulsion and boats) that you've no expertise in? Good way to get beat up when there's no need to.

Could be fun--but then it has to be on the "fun" budget, not a student tight budget.

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There's lots of "little" Honda gensets but the most common is the kilowatt model, which can be slaved together and synchronized with a twin to make two kilowatts. Or, the 2kw model. Using either one regularly on a small sailboat, without issues from refueling with the gasoline, or monoxide poisoning? Another PITA at best.
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Old 29-07-2014, 18:48   #34
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Re: Electrical Conversion

hellosailer, you should be posting in growly's thread, and go call him stupid.
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Old 29-07-2014, 19:05   #35
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Re: Electrical Conversion

Jack, I don't and didn't call anyone stupid. Unlearned, maybe. Inexperienced, maybe. But stupid? Even if that wasn't against forum policy, I don't hold it against someone even if they're intellectually challenged.

The same that Tiger Woods wouldn't insult me for being a lousy golfer.

I'm not at all sure of what you're digging at. I'm just suggesting, there are many good reason why someone who says they are on a budget, and says they have little experience, and says they're in a transition stage of life, maybe shouldn't be looking at a relatively unconventional powerplant and a project that could become a black hole.

Maybe it works for you, but as I said, he needs to compare what folks like you have done, and what you've gotten out of it, with how it might or might not work for him.

Or perhaps, you'd rather just guarantee to buy back his boat three or four years from now, if he can't unload it? You do have faith in the concept, right?
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Old 29-07-2014, 20:04   #36
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Re: Electrical Conversion

You have said he will ruin the value of his boat, that would be stupid then, right? A total loss is not a stupid thing to do??

"-it will make the boat un-sellable, basically a total loss."

Did you ever think 5 years from now, the EP boats will be selling, the diesel polluters will be banished? Like maybe wood boats today, nobody will buy them, but in the past they were great and plastic boats were trash.

Quote:
Originally Posted by hellosailor View Post
Or perhaps, you'd rather just guarantee to buy back his boat three or four years from now, if he can't unload it? You do have faith in the concept, right?
Sure, if you guarantee to buy his boat with a dead diesel today also.

I have suggested a very low cost way to get what he wants,
instead of 'investing' thousands in new equipment that might be close to more than the cost of the boat itself.
Golf-cart motors are as common as outboards, and you might ask yourself, why are golf carts pretty much all electric, why don't they use diesel engines in golf carts?

The question is whether 1.5 hours of motoring (full speed) is enough for the sfbay, that is a judgement for the boat owner to make.
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Old 29-07-2014, 20:17   #37
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Re: Electrical Conversion

1100 lbs is a lot of weight. But then maybe 400 is being removed,
so net gain of only say 700 lbs. I would hope having 4 people on board your boat (that would be just 2 of your girlfriends) would not sink your boat!

On a cat, that would be a lot of weight, and in that case, I'd go with lithium batteries, a 36volt 280 AH pack would weigh MUCH less, and not cost that much more if you know where to look.

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18 batteries! Oh sh!t. That'll sink my boat!
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Old 29-07-2014, 20:32   #38
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Re: Electrical Conversion

On the bay, he would only need an outboard if he frequently went as far as the delta. You can even sail up to Alameda... Done that. If the batteries are properly placed he will stiffen the boat a bit as well. For the real intended use of that boat its a great idea. Will smell better too. For the babe factor.
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Old 29-07-2014, 21:25   #39
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Re: Electrical Conversion

"why don't they use diesel engines in golf carts?"
Because the inevitable stink of even the finest diesel engines ruins the aesthetic experience of finely manicured courses. And of course, there is the extra licensing requiring to keep diesel refueling tanks on premises, with increased insurance costs for the storing the flammable fuel. And the greenskeeper said that if there is even one stain upon his spotless manicured sward from a diesel or oil spill, he's going to install putters in a place where the sun don't shine.

Boats aren't golf courses. Enthuse all you will, but there's no paradigm shift to electric engines coming to sailboats in the next five years. The technology has been around far longer than that, and the "new" high efficiency motors date all the way back to the lunar lander technology. Which still isn't driving many boats, or anything else besides cordless drills and vacuums.

You'd do better trying to sell Dyson on the boating market.
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Old 29-07-2014, 22:26   #40
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Re: Electrical Conversion

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Originally Posted by nimblemotors View Post
1100 lbs is a lot of weight. But then maybe 400 is being removed,
so net gain of only say 700 lbs. I would hope having 4 people on board your boat (that would be just 2 of your girlfriends) would not sink your boat!

On a cat, that would be a lot of weight, and in that case, I'd go with lithium batteries, a 36volt 280 AH pack would weigh MUCH less, and not cost that much more if you know where to look.
350 pound girlfriends? - who told you?

Oh, wait. Ya didn't notice I live in SEA. Girlfriends come in the convenient 100 pound variety. 600# per six-pack.

I'm still waiting for my flux capacitor powerplant fueled by garbage and hoverboard as promised in Back to the Future.
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Old 29-07-2014, 22:49   #41
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Re: Electrical Conversion

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350 pound girlfriends? - who told you?

Oh, wait. Ya didn't notice I live in SEA. Girlfriends come in the convenient 100 pound variety. 600# per six-pack.

I'm still waiting for my flux capacitor powerplant fueled by garbage and hoverboard as promised in Back to the Future.
Ahh, ok, I thought SEA was seattle..
so you can't have six girlfriends on your boat??
man I'd fix that, maybe the stink from the diesel keeps them away..



What has changed are lithium batteries. If you haven't noticed portable devices have all gone from NiCad to NiMH and now LiCo with lighter weight and longer life. They just need to get a little cheaper..and they will in the next 5 years I would bet on it.
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Old 30-07-2014, 05:15   #42
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Re: Electrical Conversion

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So I did a little research for Matt, and found a manual on the Ferryman A30.
It is a 10hp engine 2500 rpm, 21 lb/ft of torque.
It has a transmission with a 2:1 gear ratio. So it looks like the prop only spins a pretty low rpm, 600 to 1200 rpm.

I've suggested the low cost conversion is to use golf cart parts,
and have a GE 6.5hp 48volt cart motor max 4800 rpm,
and a Curtis 1204 24-36v 275amp controller I would let him have for $250.
At 6.5hp = 5kw, at 48 volts 4800 rpm is 100 amps.
At 24 volts, 2400 rpm is 200 amps. This looks OK.

In this case, it looks like the transmission can be used which solves a lot of problems, gives the 2:1 gears, and also gives reverse eliminates the more complicated electric reverse in a series motor.
Also very important is the thrust and prop shaft issue is already handled by the transmission. What must be done is fabricating the motor to transmission adapter. It is quite expensive to pay someone to do this, but I've already just made them myself, I have a lathe, drill press, welders, torches, etc.

Regarding batteries, if we use the figures above, we need 200 amps at 24 volts, but figure 36 volt pack. A 6v T105 does 75 amps for 100 minutes, so we need three in parallel for 225 amps, and six in series for 36 volts for a total of 18 batteries. This gives 1.5 hrs of electric motoring.
That's a nice cheap entry into electric propulsion, though for simplicity I would try to avoid series parallel Batts and just go with bigger ones in series. $250 is a nice price for the motor and controller, and a future upgrade to 48v would be pretty cheap and easy.

The motor... C face? Keyed 1" shaft, or splined shaft? Cause if it is C face and 1" round shaft, the enclosed gearbox from electricmotorsport will mate right up to it. It may be that separating the Farymann diesel from its transmission isn't doable or practical. I'm not hands-on familiar with them. Also there is the belt drive setup from Thunderstruck that takes a C face motor. Either way, no adapter would be needed if your motor is C face with round 1" shaft. But if it doesn't have to be pretty, an adapter plate can be pretty low tech to make.

Personally I think electric reversing is much more elegant and hassle free than mechanical reversing. But if the Farymann tranny can be used, it is worth considering.

Do you think 2:1 will be enough reduction? I think it would be fine for maneuvering, but would the motor stay cool after several hours of slow motoring?
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Old 30-07-2014, 07:13   #43
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Re: Electrical Conversion

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a64-
I'm not talking about posterity, but the guy's in college. Which almost always means that in three more years, max, he'll have some radical life changes coming up. Probably moving, probably changing priorities, and a very good chance that the boat becomes the wrong boat for him for any number of reasons. Either way, it would be nice to have some resale value in the boat, rather than none.
A generic 20-odd footer can always be sold for something, but once you tag on the "homebuilt/homepowered" tag, that's gonna complicate life.

Point taken, just and I am trying to say this without being offensive to the OP, but his boat with a dead Diesel may not be worth all that much, Plus look where he lives, I have never lived there and likely never will, but form my understanding it may well be THE place to sell an electric "Green" boat.
I don't have any use for an electric boat as one thing I have learned so far is that I use the Diesel far more than I want to or expected that I would have to, electric simply isn't a viable option for me, but maybe for him, it is?
There may be other advantages too, like if you can use the electric propulsion only sparingly, you have the house bank from hell, especially if your longest time out is a weekend.
Personally I would love to have the capability to noiselessly slip into and out of my marina without the noise, vibration and heat that comes from the Diesel.
Nothing wrong with fitting an outboard on it though, and as you said I'm sure that would be more practical, but doing an electric conversion might be more fun
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Old 30-07-2014, 12:33   #44
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Re: Electrical Conversion

I agree that electric reversing with a brushless motor is MUCH better.
No need to stop the prop, no clunks, no mechanical linkage,
but can that justify the cost? I'd get Lithium batteries first instead if I had a bigger budget.

The 2:1 will be OK with this cart motor, it has a lot of mass/surface area.
I would remove the internal fan and use an external one.
Not sure it would be OK with the pancake motor.

The cart motors have an open can that bolts to a differential that has the bearing for the rotor. They need a bearing setup for other applications.

The gear reducer from EM at 28lbs and cast iron and $460 doesn't appeal to me. I have a rx7 transmission I'm trying to sell for $50, or heck I have a 7.5 ford irs differential in my shed with 2.7:1 gears I think, free is about the right price here. A belt drive looks like the simple general solution, easy to adjust the ratios that way, and no fluids to change and leak.

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Old 30-07-2014, 13:14   #45
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Re: Electrical Conversion

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I agree that electric reversing with a brushless motor is MUCH better.
No need to stop the prop, no clunks, no mechanical linkage,
but can that justify the cost? I'd get Lithium batteries first instead if I had a bigger budget.

The 2:1 will be OK with this cart motor, it has a lot of mass/surface area.
I would remove the internal fan and use an external one.
Not sure it would be OK with the pancake motor.

The cart motors have an open can that bolts to a differential that has the bearing for the rotor. They need a bearing setup for other applications.

The gear reducer from EM at 28lbs and cast iron and $460 doesn't appeal to me. I have a rx7 transmission I'm trying to sell for $50, or heck I have a 7.5 ford irs differential in my shed with 2.7:1 gears I think, free is about the right price here. A belt drive looks like the simple general solution, easy to adjust the ratios that way, and no fluids to change and leak.

In light of Matt's budget restraints, I guess that sounds pretty good. So the motor accepts a splined shift from a gearbox? Tbh, I wish sometimes that the Motenergy motors were like that, so some axial wiggle room was possible. Anyway looks like you have a viable solution with some decent transmission options there. Should work. If I was still in the planning stage I would definitely consider your solution.
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