Wow Craig that sounds pretty cool. I am looking forward to your progress reports!
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Mine was annoyingly noisy if the drive shaft pressed down on the
gears in the foot. With the motor coupling adjusted so it didn't, it
was quite quiet.
(Unit: 'Honda 75' 7.5HP)
=====
And while I'm writing, here's a potential new improvement for
outboard conversions...
Presently I'm prototyping a novel configuration of reluctance motor,
first model maybe 4500W. If it works well, the steel rotor with no
magnets or wires to break loose should be good for quite high RPM.s,
compensating for the gear reduction at the foot of most outboard
legs. I've prototyped the motor controller, which should be
inherently more reliable than typical BLDC controllers. (Little or no
chance of destructive shoot-through currents.) There'll be a few
photos of the build in monthly Turquoise Energy News #91 in a few
days.
As it is simple and has no supermagnets this motor should be
relatively cheap, and easy to assemble. (And I have created a second
somewhat similar design that looks probably even better! I conceived
them both this month. The first one is half built, so it gets
finished.)
Craig
http://www.TurquoiseEnergy.com/
Victoria BC
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There are special fire extinguishers but they are big and very expensive. They are the same type used to extinguish magnesium fires. You will find demos on youtube.
On Aug 28, 2015, at 7:57 PM, Anton antonherbert@earthlink.net [electricboats] <electricboats@yahoogroups.com> wrote:
Thank you for that Jason, it was useful information for wrapping my head around sizing the pack for my boat.Can anyone speak to the fire risk of these Chevy volt batteries?I believe they are lithium magnesium. (Different from cobalt?) Are these significantly more dangerous then the liFePO? Are there fire extinguishers that would put out such a fire? Could you put them in a fire proof box? (So much for the weight saving!)Any thoughts on the risks or strategies to mitigate the risks would be helpful.Thank you!Anton
On Aug 28, 2015, at 6:13 AM, Jason Taylor jt.yahoo@jtaylor.ca [electricboats] <electricboats@yahoogroups.com> wrote:I have a "1 hour" battery pack. That means my 5kw system, in my 4 ton boat has a 5kwh pack. I find it sufficient for club racing and day sailing in my river/lake with a 1kt current. And not much more. You may want to consider a single pack for testing and moving the boat about the marina, but for venturing further than a few (under 5) miles, you'll definitely want to have at least a 4-pack of those batteries.The general consensus for a standard install is 1kw/ton for motor power and about 2kwh/ton for battery storage. So being a 10ton boat, you would want at least a 10kw motor -- the AC35@48V & 500A can develop up to 25Kw so you're good there. But if you want any kind of range, you're going to want at least a 10kwh battery pack (5 of the Chevy Volt packs you mention), but a 20kwh pack may give you a better operational envelope. The Westsail 32 is a heavy displacement, sturdy boat that can handle some really rough conditions. Your motor seems well-sized to power it. But only 4 Chevy Volt packs may not provide the boat the energy storage capacity it would need to perform under those conditions.I am also interested in learning more about these packs. That seems like a very good price./Jason
On Aug 27, 2015, at 16:31, Anton antonherbert@earthlink.net [electricboats] <electricboats@yahoogroups.com> wrote:I am considering the Chevy volt batteries in my conversion.The guy in Livermore who is selling them assures me that the water ducts are not for cooling but for heating the battery in cold climates.$550 for 48v @ 45 amp hour plus $200 for the bms. I am thinking of getting 3 or 4 to start with. My system is the thunderstruck ac35 on a Westsail 32 (full keel 10 ton sailboat)Any thoughts? Concerns? Advice?Thank youAnton Herbert
On Aug 10, 2015, at 10:48 AM, mark.internet@yahoo.ca [electricboats] <electricboats@yahoogroups.com> wrote:Has anyone tried a chevy volt battery pack in a boat.
They appear to be reasonably priced for the AH's.
It looks like they have 48 volt and 24Volt modules.
They are water cooled and maybe one could add a pump and run lake water through them for cooling.
if someone has used one please let us know how it works
Thanks
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I have a "1 hour" battery pack. That means my 5kw system, in my 4 ton boat has a 5kwh pack. I find it sufficient for club racing and day sailing in my river/lake with a 1kt current. And not much more. You may want to consider a single pack for testing and moving the boat about the marina, but for venturing further than a few (under 5) miles, you'll definitely want to have at least a 4-pack of those batteries.The general consensus for a standard install is 1kw/ton for motor power and about 2kwh/ton for battery storage. So being a 10ton boat, you would want at least a 10kw motor -- the AC35@48V & 500A can develop up to 25Kw so you're good there. But if you want any kind of range, you're going to want at least a 10kwh battery pack (5 of the Chevy Volt packs you mention), but a 20kwh pack may give you a better operational envelope. The Westsail 32 is a heavy displacement, sturdy boat that can handle some really rough conditions. Your motor seems well-sized to power it. But only 4 Chevy Volt packs may not provide the boat the energy storage capacity it would need to perform under those conditions.I am also interested in learning more about these packs. That seems like a very good price./Jason
On Aug 27, 2015, at 16:31, Anton antonherbert@earthlink.net [electricboats] <electricboats@yahoogroups.com> wrote:I am considering the Chevy volt batteries in my conversion.The guy in Livermore who is selling them assures me that the water ducts are not for cooling but for heating the battery in cold climates.$550 for 48v @ 45 amp hour plus $200 for the bms. I am thinking of getting 3 or 4 to start with. My system is the thunderstruck ac35 on a Westsail 32 (full keel 10 ton sailboat)Any thoughts? Concerns? Advice?Thank youAnton Herbert
On Aug 10, 2015, at 10:48 AM, mark.internet@yahoo.ca [electricboats] <electricboats@yahoogroups.com> wrote:Has anyone tried a chevy volt battery pack in a boat.
They appear to be reasonably priced for the AH's.
It looks like they have 48 volt and 24Volt modules.
They are water cooled and maybe one could add a pump and run lake water through them for cooling.
if someone has used one please let us know how it works
Thanks
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I've been looking at the various "build it yourself" options and ran across the LiFePO4 3.2v
"canister"s from Headway. My question is for the battery guru's concerning their 3810HP 8Ah @
$15.00. I notice that is has advertised 10C max charging (80A) and 20C (160A) max continuous
discharge current with max momentary discharge of 25C (200A).
see http://rightbikeonline.com/index.php?route=product/product&product_id=73
My project is typical, 33' sailboat, 3500 lbs, Cushman GE motor w/ brushes, original trans from the
diesel and a folding 12 x 12 prop. Mostly dry sailing on a lake (lauched from a trailer each
visit), so the boat only needs the aux elec motor less than 20 min on an ideal day (I go to sail).
But could be used for more than a hour or 2 when there is no wind, or outrunning a rainstorm.
I have the following table of estimated power requirements;
Knots HP/ice HP/elec watts Amps@24v Amps@36v Amps@48v
3.4 1 0.3 213 9 6 4
4.3 2 0.6 426 18 12 9
4.9 3 0.9 639 27 18 13
5.4 4 1.1 853 36 24 18
5.9 5 1.4 1066 44 30 22
6.3 6 1.7 1279 53 36 27
6.6 7 2.0 1492 62 41 31
Hull speed is about 6.7 knots
If I was on the coast I would definitely go with 50% more power but many boats this size have 6HP diesel motors.
What I think I see is these canisters provide quick charge capacity and ample heavy use capacity in
a 3/4 lbs package so that 15 in series gets you to 48v @ $225 for about 2 hours use at 3.5 knots, 1
hr use at 4.5 knots or only 20 mins at 6 knots (2 miles across the lake to outrun a storm). At
only 11.25 lbs so that if made modular [(3 x 1.6) x (5 x 1.6) x 4.75] or 5" x 8" x 5" 48v 8A
package. Obviously I would want to build two or three but at around twelve pounds you could carry
them from the boat to be charged better than a 62 lbs 6 volt Trojan.
Also they show the cell dropping to 7 amp after 500 cycles of 10C charge and 10C discharge. So my
question is does it make sense to buy these and probably only discharge at an absolute max of 4C
compared to their 38120L/S 10Ah with 3C max charge and recommended 1C (10A) discharge (3C 30A max
discharge) their chart shows 7.7A @ 1440 cycles 1C.
see http://rightbikeonline.com/index.php?route=product/product&path=62&product_id=68
Actually, after writing all this down it looks to me like the 38120S/L 10Ah is a better match to
the 4 to 30 amps required to go 3.5 to max hull speed with only one 15 series string. (To be
improved with a second pack down the road.) One thing that hit me was trying to actually get 1440
cycles means every day at the lake for 3.94 years. So I can afford the battery pack I just can't
get that much time at the lake???
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I just thought of something. Is the lower unit well-used? could be the thrust bearing is worn and the gears do not mesh properly in fwd anymore. Which would be why it might be quieter in rev.
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Good for you, John. I hate to see a decent technology get discarded simply because the company decided not to support it properly anymore. I bet they decided that the brushless motors lasted too long and would impact future sales. Typical corporate greed.
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For a brushed motor, that would be a good way to get home if the controller blows. But for routine use, it's probably not a great idea to tap your bank like that. The battery discharge will be different from one batt in the bank to another. I actually considered using a brushed motor just because I could in an emergency power the motor directly from the batteries, but decided instead to keep a spare controller. (and a spare motor, too!) I would MUCH prefer, if using a brushed motor, to have proper PWM speed control of the motor, at least for the primary means of powering the motor.
Better than simply tapping the bank, consider paralleling the bank so you get full use of all batteries at 24v, and at 12v. Could be done with relays, or manual connections in a pinch. Just be aware that line losses can be astronomical at the 12v level.
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I use flooded lead acid batts in my sailboat, but weight is not really an issue for me. In a canoe, weight vs range might be more important. So consider a couple of 20ah 36v Lithium ion e-bike battery packs. They are very light and you can run them down much further than lead acid batts, without seriously shorttening the lifespan. Lead batts shouldn't be discharged to below 50%, and 60% would be better. Also think about going 48v. Doesn't cost much more. More efficient because higher voltage allows the same work to be done with lower current, reducing line losses for a given cable size. But yes, your proposed system will work. It could work better, though, done differently.
Yes the lithium packs cost more but for what you want, its not that much. I just bought a 48v 20ah pack for $490, shipped. I use it on my e-bike and I seriously considered getting 10 more as money allows, for a second bank for my boat. Even just a couple of them would be a nice little reserve bank. Some guys buy loose cells and build their own banks. Even salvaged cells from lapop batteries. Just sayin. Not doin.
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Often this is a practical approach. However, a larger prop turning more slowly can be more efficient. Particularly if it prevents the prop from cavitating significantly. I would not want to try pushing my boat with a 8" prop turning at 3200RPM, for instance. I would much rather be pushing the boat with say a 12" prop turning at half that speed while keeping the motor speed where it should be. YMMV of course. More than one way to skin a cat.
Some motors in some applications will work just fine without reduction gear. But remember, if there is no thrust bearing in the motor directly driving the prop, you will still need an external thrust bearing. Thoosa is the only one that I am aware of that has an integrated thrust bearing that can accept reasonable axial loading. Motenergy, Golden, etc will need a thrust bearing, and any gearbox suitable for marine propulsion use will be able to handle the thrust. So there is another reason for a gearbox.
However, a gearbox is not the only way to get reduction. Smaller boats in particular often use a belt and pulley system with a thrust bearing on the prop shaft. Motorcycle chains and sprockets work too, but they can sling oil. The one advantage of a chain is the chain can be broken to change a sprocket or whatever, or an ACTUALLY broke chain can be repaired or replaced, without needing access to the end of the shaft. For instance, it is a simple matter to mount a sprocket on the output of a transmission on a diesel, mount the motor up above that sprocket, and run a chain around the motor sprocket and the prop shaft sprocket. If you try the same trick with pulleys and belts, you have to decouple the shaft somewhere to slip new belts on should the old ones break.
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Generally how the potentiometer is used, is it is in series between a 5v signal and a return, and the moving contact gives you the 0-5v signal that the controller uses for speed input. A hall effect throttle unit can do the same thing. You can even manually apply an external DC signal referenced to the controllers RTN line. However, if you want forward and reverse from the same operator throttle control unit, you will need to design something to drive a fwd/rev relay or transistor that senses when the throttle lever has been moved from the center neutral position, and deliver a speed signal in such a way that all the way FWD is full ahead, all the way REV is full astern, and near the center neutral setting is dead slow, and the neutral setting of course is all stop. This is most easily accomplished with firmware from within the controller itself. Otherwise you have to engineer something to do the job.
This is a worthwhile thing to have. It makes operation much more intuitive and you are not fumbling around for a switch to go into FWD or REV, and having to remember to always return the throttle to stop. I have such a setup on my boat, using just a simple pot and a firmware upgrade to the controller.
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Oh no, I don't think you should step up the ratio. You want a reduction. The foot should have adequate reduction already so direct drive to the driven shaft should be in the ballpark, but if you want to get seriously into the engineering aspects you can calculate the ideal total ratio for a given prop, based on the optimum power/speed curve of the motor. Electric motors hate to be driven under load at insufficient speed. They tend to overheat, for the main thing. Of course you don't want to overspeed the motor, either. Usually there is a constant published for the motor, and multiplying it by your system voltage will give you the ideal speed to run the motor at full power. For a displacement hull, if the motor is sufficiently powerful, full power setting should be about hull speed with a clean hull and prop. So if you know what prop RPM will give you that speed, you can calculate the desired reduction ratio, keeping in mind the ratio you already have in the foot of the outboard.
I am not using an outboard. I simply replaced my old Atomic 4 with electric. My reduction gearbox is fully enclosed and made by Baldor. They only make whole number ratios, such as 2:1, 3:1, 4:1, etc. Mine is a 2:1 unit. Thrust bearing is integrated into the gearbox. This unit is fairly compact but It it probably not what you want for an outboard.
You do need a tachometer of some sort to figure out where you are at on motor RPM.
Adjusting prop size and pitch to match the load (hul) and motor properly is probably going to be much simpler than diddling with the gears.
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