# EV Conversion of 30' Sailboat Inboard



## dimitri (May 16, 2008)

I have no idea what power levels are required in 30' sailboat, but I suspect the AC system discussed in this thread might work for you
http://www.diyelectriccar.com/forums/showthread.php/hpg-ac30-31-50-owners-thread-34853.html

Do not use marine batteries, they are not meant for current levels involved in EVs. You would be better off with large prismatic LiFePo4 cells. Number of cells (pack voltage) is decided based on motor controller operating range, then cell size is decided based on power and range needed.

What kind of budget do you have in mind?


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## Bottomfeeder (Jun 13, 2008)

Since weight is less of an issue on a sailboat, (It probably has a big heavy keel anyway) I'd go with trusted Lead Acid for your batteries. If you can access and maintain them, then I'd go with flooded lead acid. You're gonna need the money for the AC system and PV cells.

You're going to need to do some calculations for how much power and capacity you're going to need. As you know, it doesn't take much to get in and out of a slip. But how long will you be expecting to cruise with the motor going? Is this a day sailer or are you going around the world? There are a lot of factors to consider. Do some rough estimates of what you're expecting to get out of the system. Then you can start to get an idea of size of the motor, voltage, capacity, etc. Also, you'll need to figure out your PV needs. Many people are surprised to learn how much area of cells is needed to get a decent wattage out of your solar system. Especially when the cells aren't optimized by being pointed straight at the sun.

If you do the calculations on the forum, people can check your math.

Cheers!


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## paperdoor (Mar 11, 2010)

Hey thanks Dimitri and Bottomfeeder for your replies - 
I spent a few hours on the web the other day researching EV and sailboat inboard conversions. 
My plan is to use the EV system to get me in and out of the marina, and a little help when tacking up a narrow channel or getting in an out of the inlets against a strong tide. 
I was recommended at least 15hp from a sailing friend of mine, he's running a 25 horse diesel and he says he has more than enough power for his 30 footer.

I read a geat article from 2003 of a conversion for a 36' sailboat- 
His system included:
36 Volt DC electric drive. Consisting of:
One Advanced DC Model A 89 electric motor rated at about 4 kW
One Lester Electric Company 36 Volt battery charger rated at
25 Amps
One Curtis 1204 DC motor Controller
One bank of 36 Volt power, consisting of six Trojan T-105
6Volt golf cart batteries, each holding 220 Amp hours of "juice"
here is the full article:
http://groups.yahoo.com/group/columbiasailingyachts/message/35923 
He gave a price of around $1500 for the whole system including batteries.

I'm interested in AC however for 2 reason, brush-less and recharging of the batteries while at sail. 
Do AC motors require more power?

I will be rigging PV Cells on adjustable brackets so that I can adjust them to the sun, with enough output to run my laptop and monitor for a few hours a day. Cruising time per day would probably only be at most 3 hours. I'll put together some math on that (being terrible at math thats going to hurt) when I get to the PV cells. 

I also found a site that sells a kit for sailboats up to 30', which includes everything minus the batteries. 
http://www.electricmotorsport.com/store/ems_marine_brushless_drive_kit.php
The kit goes for $1450.00

But I know I have enough knowledge to build my own system , I'm just not sure on how the numbers should add up. All I know is a lower number on the cost is better for my wallet.


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## paperdoor (Mar 11, 2010)

I did find this motor on a golf cart parts site. 









The Price is right, It has enough HP- 
I'm guessing I would need :
48v of batteries.
Charger
Controller -what kind/rating I'm unsure of?
as well as throttle, I would like to convert the existing throttle on the boat if that is possible?
Fuse? Breaker?
????
I'm going to make a phone call to one of these dealers and see if I can pick their brains, but you have to remember , they are trying to sell you something, bias maybe?


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## dimitri (May 16, 2008)

I thought AC was important for you, this motor is DC.


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## paperdoor (Mar 11, 2010)

Well, that just goes to show my knowledge so far - How can you tell, I don't see specs. All I was looking at was the price.


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## dimitri (May 16, 2008)

Low voltage is a dead giveaway, there are no AC motors for 48V. Also pic is showing 4 terminals, 2 field and 2 armature, AC motor has 3 terminals.


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## paperdoor (Mar 11, 2010)

Gotcha , ty.


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## dragster (Sep 3, 2008)

Hi
I have an AC system in my Ford Explorer and I love it however it will not regen in your boat. I have a 39 foot sail boat and there is no way that prop will turn over the motor. Go with a DC drive it is the lest expensive, 15HP will be more then enough power as for lead battery's you will meed a lot of them witch will be to much weight. You speed will be 6 knots and it can take sometime to get from point A to B and remember there is not always wind and sometimes there are very strong currents. So Lithium is the best bet and lots of them.


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## maxvtol (Nov 11, 2009)

Don't know anything about these, but looks like some good info. Check out their other motors, too.
Thunderstruck Sailboat Kit


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## paperdoor (Mar 11, 2010)

Yeah I did take a look at that site, looks like a good deal, trying to find out if anyone has used their system.


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## RedBellies (Mar 27, 2010)

The issue here is longevity. You can certainly put that ETEK-R and Curtis into your boat, go down to WalMart and get yourself a dozen lead acid Everstart batteries but the problems you'll find with that gear are going to cost you more in the long run. 

The Etek can't handle the thrust that a prop shaft will place on it and you'll burn the bearings out of your first attempt. Then you'll spend $1200 for a custom stainless mount and another $450 for another Etek. 

Then you'll burn up another Etek because it can't handle the start up load. So you redesign your mount to accomodate a 3:1 reduction belt drive. 

And by the time you've done that, the useful life of your Everstarts is up so now you have to shell out another $1000 for a new bettery pack.

You get what you pay for. You really do.

Buy an Agni 95. It's more expensive but you can direct drive a 12" three blade prop because the chassis is BUILT to withstand the thrust of a prop shaft.

Buy 6v fiberglass mat batteries. The Agni will run at half throttle for 6 hours on 48 volts of 220mah batteries. Yes they will cost you 4 times as much as a lead acid battery but they will last you ten times as long and give you more power and much longer range.

You're going to need 200 watts of solar panel. Do you have that much deck space? Consider an Air-X Marine wind generator, and as a last resort a small Honda gas generator. The prop turns under heavy sail and that offers regeneration. The Air-X turns under any wind. Out on a cruise and no wind for a few days? With a generator you have a hybrid. My Honda 3800 runs about 8 hours on a gallon of gasoline and is very quiet.

This doesn't need to be difficult. Electric saildrives have been around for a very long time. If you spend your dollars in the right place you'll only need to spend them ONCE.


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## BMI/LiFeTech (Aug 12, 2009)

paperdoor said:


> I'm considering AC from what I have read so far, if the propellor is going to spin while at sail, then why not use that energy to recharge the batteries.
> 
> AC or DC?
> How many HP motor do I need - I would be happy with a 9 to 25 HP Gas or diesel motor to get the boat out of the inlets on incoming and strong tides, http://www.torqeedo.com/us/hn/products/cruise-r.html Torqueedo writes that their 4.0R (Im guessing that stands for 4HP) is equivelent to an 8 HP Gas motor - ?


Forget wasting your time on the AC regen for a boat. You get very little power back and from several boat owners who have tried it is just not worth it. It is far more economical to put extra solar panels on the boat for battery charging.

A good resource for electric boats is the EBAA website-
http://www.electricboats.org.au/

The most powerful motor Torqueedo currently make is the Cruise 4 (4kW). This is equivalent to a 9.9HP gasoline outboard.

We are fitting 3x Cruise4 motors to the 55ft, 8 tonne racing cat "Room With A View" with computer diagnosis of battery errors, battery cycles monitoring and checking of individual cell voltages by plugging in lap top computer into a data data connector which will be fitted to the instrument panel.
The boat and batteries are pictured below-


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## GrowleyMonster (Apr 7, 2014)

I will soon be going electric with my boat, a Cal 2-27. Not an expert by any means but I will share what information and ideas I have.

First, the motor. The two most popular motors fir DIYers in the US with boats under 40 feet are the ME0907 and ME0913, both brushless, both made by Motenergy. At 48v the 0907 is good for about 6hp continuous, the 0913 for about twice that. Both have much higher peak output but only for a minute. At 7600lb I can get by with the smaller one. You might go with that one too, but if you have to run any dangerous passes where headwinds and seas are an issue, go with the 0913. Neither one will allow you to violate the laws of physics and push your displacement hull significantly over hull speed, but contrary conditions that might have you going nowhere with the 0907 won't stop you with the 0913. If this won't be a problem with you, the smaller motor is a couple hundred bucks cheaper and the controller will be cheaper too. There are other motors you could use but these have a wide user base and a good track record.

You can't use a brushed motor if you have gasoline or propane accessories or equipment onboard. Plus brushes eventually need to be replaced.

You will want a reduction gear of some kind because the motor will want to turn at around 3000 rpm but your prop likely will work best turning much slower. Typical ratios are in the range of 2:1 to 3:1. Each motor has a voltage/speed constant, maybe 50, maybe 67, somewhere in there. Multiply it by your voltage and that is the rpm you should be running to get the boat at or just under hull speed. You already know what prop speed will do that for you. Let's say it is 1000 rpm and your motor speed is to be 3000 rpm... well, that's 3 to 1. So the driving pulley of a belt drive would be 1/3 the circumference of the driven pulley. As the motor turns 3 revolutions, the prop turns just one.

You can accomplish this with belts and pulleys, chains and sprockets, planetary gears, bevel gears, whstever. Home brew or prefab. Thunderstruck.com has a timing belt reduction gear similar to what most homebrewers do. The motor is over the stuffing box, shaft pointing forward. This conveniently puts the motor in the proper rotation for a right hand prop. Looking at the shaft end of the motor, the shaft turns to the left, counterclockwise. Yes the motor can run in reverse but not continuously, because the cooling fan works best the other way. So you have to ensure proper rotational direction of the motor by either the orientation and the reduction gear configuration, or by switching to a left hand prop. Just remember that with a left hand prop, the stern will back to starboard and not to port. A planetary gear setup would need the left hand prop. A simple pinion or bevel gear setup with the motor pointing aft would have the proper rotation. You can also install a bidirectional cooling fan.

Somewhere in your drive train you need some sort of thrust bearing, to transfer all the pushpush of the prop to the hull and not just let the shaft slide forward. These motors do NOT have a built in thrust bearing, and don't hold up well under any axial load. Another reason for the reduction gear, which is usually where the thrust bearing is located.

Kelly and Sevcon make controllers for these two motors with reversing and regen. You could use an Altrax maybe, and use a reversing contactor for reverse, but you would have no regen. The right prop and controller will give you some regen capability, though for a day sail with light winds it won't be enough to make any difference, so depending on your situation you might just forget about regen charging your batts. Regen makes a difference on a long voyage with respectable speeds under sail. A bigger boat with a higher hull speed that makes ocean crossings would be well advised to have regen capabilities.

The batteries are of course the part of electric propulsion that we love to hate. A good rule of thumb is you don't discharge the bank below 50% except in an emergency. The capacity in amp hours is at the 20 hour discharge rate, and at the currents we use, figure 80% of that, so your usable energy storage is roughly 40% of the rated capacity. You want to be able to run an hour at your hull speed, or close to it, if you are like most of us.4 group 8v batts will probably come close to that, at roughly 150 lbs each. So 600 lbs of batts and maybe 100 lbs of motor, charger, cable, etc are replacing maybe 450 lbs of engine and fuel tank. A 30 foot boat shouldn't see a noticeable difference. After all, your average guest is probably 150 lbs. For slightly less capacity but significantly less cost you could go with gc2 6v golf cart batts from costco, maybe even two banks of them, or a reserve bank of group 31 or even group 27 12v batts.

Imagine that you have a diesel engine, and your fuel tank is a beer bottle. A 600 lb beer bottle that still holds only 12 ounces. A beer bottle that cost $1k or more. That's part of the fun of electric yachting.

Another name for the lead acid flooded cell battery is "ballast". You can spend a ransom for fancy pants lithium batteries with a higher energy density but nah. AGM batts have advantages for a more modest price increase, but most electric sailors go with the regular flooded cell type. YMMV. 

Make sure you go with a proper smart charger with a high enough bulk charge current for your bank. I would not consider a charger that did not bulk charge a 48v bank of 200ah or bigger at less than 15 amps. 

Wind and solar are a whole nother project, best left for after you get your electric engine running good. But let me say this... you NEVER get the watts you are "supposed" to get out of solar panels or a wind genny. Figure maybe you average 10 watt hours a day from a 200 watt solar panel, for instance. To go completely off grid is possible, even for the electro pushed boat, but it will want both solar and wind systems, of respectable size. 

Meanwhile shore power is cheap. Some guys keep a small portable generator, too. If you have room for a small diesel genny, you might look into that. A used one, maybe even an old 1 cyl Lister or Petter from an old shrimp boat might make a good project. The way they usually smoke, you would think they run on coal, and you can hear them from 5 miles away and they vibrate like you wouldn't believe but you can sometimes find one that runs just for hauling it off, and no more than $1k or so. They are amazingly rugged little engines, and hand start, with a decompression lever. Not bad if you only need it occasionally. I would hate to have to run it daily, though.

Oh yeah, the once popular SolidNav all in one electric drive can sometimes be found, even though the company I believe is out of business. Very nice setup if you ask me. Just add batts.

Last, don't skimp on the wire. High current DC needs big wire. At least #2 welding cable, and try to keep the runs short. It will significantly increase efficiency. This is not the place to go low budget.


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## GrowleyMonster (Apr 7, 2014)

OOPS my first post here, and it was a reply to a 4 year old thread! I will go hang my head in shame now.


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## sunworksco (Sep 8, 2008)

I think a great idea would be to use a used Chevy Spark drivetrain from a wrecked car. You could use the dual output shafts, one for the prop and the other for a pump. The prop shaft can be hooked up to a belt drive reduction gear system.The wrecked cars are providing excellent battery packs, as well.


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## Magman (Jul 5, 2012)

GrowleyMonster, do not hang in shame! The info you shared is excellent! I am in the planning stage of converting my 26' Wellcraft into a hybrid and found what you wrote very informative. Good Job!


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## Karter2 (Nov 17, 2011)

GrowleyMonster said:


> ?.......
> Another name for the lead acid flooded cell battery is "ballast". You can spend a ransom for fancy pants lithium batteries with a higher energy density but nah. AGM batts have advantages for a more modest price increase, but most electric sailors go with the regular flooded cell type. .......


You are overlooking the "life/cost" factor.
Whilst the lead may save you $$$s initally , you will have to replace them several times before the equivalent Lithium cells would fail.
That " ransom" for lithium is actually a smart , cost saving, investment !


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## GrowleyMonster (Apr 7, 2014)

Magman said:


> GrowleyMonster, do not hang in shame! The info you shared is excellent! I am in the planning stage of converting my 26' Wellcraft into a hybrid and found what you wrote very informative. Good Job!


Hi Magman. What is your setup going to consist of?

So far I have pulled my engine, fuel tank, and associated pipes and hoses and wires and cables. I have installed a 48v bank consisting of 8 GC2 6v golf cart batteries, and a 48v charger. My Kelly KBL48301X controller, Motenergy ME0201014201 motor, and homemade portable control box are wired together and the motor spins nicely in either direction. Motor is temporarily bolted to a enclosed gearbox reduction gear. My steel should be arriving within the next couple of days and I can start fabricating my mount. So my conversion is about 80% complete. If you run into doubts or difficulties along the way, let me know and I can at least tell you what I did.

So far, after selling the old Atomic 4 for $300, I have a net investment of about $2200 in the repower. As well as a bunch of splinters and skinned knuckles and assorted dings and bruises. It has been a lot of work though. If I had to do it over and if I had the money I would have done things differently but I should soon be finished and I believe I will be happy with the end result.


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## Caps18 (Jun 8, 2008)

Make sure to post some pictures when it is all finished. I would like to do this in a few years...once I forget how much work converting a truck is.


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## GrowleyMonster (Apr 7, 2014)

I just got my electric drive working on my Cal 2-27. Still a little more work to do. Final alignment, paint the steel parts, and replace temporary (for ease of movement) 4ga wires with 2/0 cable. Also haven't installed any meters etc yet. But I did motor from my temporary berth at pier 5 to pier 2, our party pier, and back later after a celebratory drink.


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## rotlis (Dec 26, 2015)

GrowleyMonster said:


> I would have done things differently


Hi GrowleyMonster. I got an old Sparkman and Stephens 30' sail yacht with quite dead inboard diesel. Repair is theoretically possible but will not be cost-effective..
Can you please share your findings/advices to the person who is about to start the same journey that you have just accomplished?


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## Samson (Jan 23, 2018)

GrowleyMonster said:


> I will soon be going electric with my boat, a Cal 2-27. Not an expert by any means but I will share what information and ideas I have.
> 
> First, the motor. The two most popular motors fir DIYers in the US with boats under 40 feet are the ME0907 and ME0913, both brushless, both made by Motenergy. At 48v the 0907 is good for about 6hp continuous, the 0913 for about twice that. Both have much higher peak output but only for a minute. At 7600lb I can get by with the smaller one. You might go with that one too, but if you have to run any dangerous passes where headwinds and seas are an issue, go with the 0913. Neither one will allow you to violate the laws of physics and push your displacement hull significantly over hull speed, but contrary conditions that might have you going nowhere with the 0907 won't stop you with the 0913.
> 
> ...


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## Duncan (Dec 8, 2008)

Hi Samson

Dunno about motors for that - there are lots available but for batteries you are best with OEM batteries from a crashed car
Leaf, Volt, Tesla
From what I have seen and considering a marine environment I like Volt batteries


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## GrowleyMonster (Apr 7, 2014)

Samson said:


> GrowleyMonster said:
> 
> 
> > I will soon be going electric with my boat, a Cal 2-27. Not an expert by any means but I will share what information and ideas I have.
> ...


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## Samson (Jan 23, 2018)

Duncan said:


> Hi Samson
> 
> Dunno about motors for that - there are lots available but for batteries you are best with OEM batteries from a crashed car
> Leaf, Volt, Tesla
> From what I have seen and considering a marine environment I like Volt batteries


Thank you for your time Duncan
But second hand car batteries are still well over a thousand dollars, I agree they would be better but my pockets are not that deep. 
18650 batteries can be bought for $1 each and the figure I mentioned above of 350Ah can be achieved for only $100 and they can be welded in series or parallel to create the nescesary 36 or 48V. I am thinking of ways of keeping the salt air out... silicon grease or water tight box or both... cooling is then an issue.


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## Samson (Jan 23, 2018)

GrowleyMonster said:


> Samson said:
> 
> 
> > I would not go with 36v unless it was for a very small boat like a canoe or kayak type boat. Higher voltage means less current is needed to do the same work. Higher current increases line losses proportional to the square of the current. Also at higher voltages even the same voltage drop is less consequential than at a lower voltage. From a purely electrical standpoint, you should be looking at between 200v and 600v but finding compact lightweight marine motors that turn slowly enough at that voltage level is problematic, and also on boats the wiring and electrical standards are different at what is considered lethal voltage (above 50v) and non lethal. 49v is of course an arbitrary number and in the real world 50v can kill and 51v can certainly be quite survivable but there it is. 48v is the sweet spot for boats of this size.
> ...


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## GrowleyMonster (Apr 7, 2014)

Yes you can go series or parallel or both, which you would with those cells. 100 cells in series would be 3.5ah at 400v. 100 in parallel would be 350ah at 4v. Either way it is 1400w. 100 cells will not do what you want to do. You need a bank that is 12S x 100P to get the voltage and the capacity that you specify. It will absolutely NOT be cheaper than ordinary golf cart batteries. Don't count on $1/ea 18650 cells to be up to specs or even close to evenly matched. You really would need to go with good quality cells like genuine Panasonics, and you won't get them for $1 I don't believe. Watch for fakes if you buy online. LiIon batteries can fail (burn!) catastrophically and tragically. The BMS to properly and safely manage this stack will not be cheap even if you design and fabricate it yourself which is not a trivial exercise. What are the chances of a spectacular and deadly fire? Pretty small. What is the payoff, at sea, in this rare event? Probably death. In a car, you can always pull over and bail out and run like hell and watch the fireworks. A series of flooded lead acid batteries, proper deep cycle traction batteries, is the way to go, especially on a budget, IMHO. I use 220ah GC2 size golf cart batteries, which are the biggest bang for the buck there is. If you want more capacity you can go with L16 batteries which run about 350ah I seem to recall. BMS not necessary if you know how to maintain flooded batteries. That will save you another large sum of money.

I think you are being much too optimistic about this project, TBH. At this point your smart move, before you spend any money, is to crew for someone with an electric sailboat for a few days or weeks, and get a first hand look at what is needed and what you can expect. 

Remember that you will need to be able to vary and monitor the output of your DC generator. A fixed 48.0 VDC output will not be very good at charging your batteries. Study the charge regimens for the various common types of batteries. Most if not all are best charged in multiple phases. You might for instance first use a bulk phase, where current is kept constant and voltage rises naturally as the bank charges, and then an absorption phase where voltage is kept constant and current gradually drops, and then a topping or float stage where the final 1% or so of juice is squeezed in there and maintained with a fixed small current that just maintains full voltage. Then with flooded batteries you will also want to equalize a couple times a year. The equalizing voltage for a 48v bank of flooded batteries is around 62v. You could of course equalize them separately, 7.25v. A large Variac and a rectifier from a stick welder makes a dandy manual charger that you would run from shore power in port. This could be dangerous if you do not know what you are doing. Very few "smart" chargers actually apply a proper equalizing charge, no matter what the vendor claims. I have only seen one.

You definitely have some homework to do on the battery. One fun project you could undertake that would be an excellent learning experience is to find a cheap golf cart, preferably with dead or dying or missing batteries, and build a 48v pack for it out of your 18650 cells. Don't forget the BMS. Use it, charge it, store it, use it, monitor, experiment, and be ready to run like hell if it starts to sizzle and sputter. If get really confident about it, then you already have your boat battery in the bag. You can maybe use your golf cart as a NEV, depending on local laws. 

Take vendor claims of hull speed at x tons with a grain of salt until you actually see it in person. Often vendors will use peak power rather than sustained power. Peak power typically means what the system can stand for 60 seconds. Another reason to crew for an e-boat owner and get a real world handle on things. Put it this way... 1HP = what... 746w? Multiply voltage times current, and divide by 746 for estimated HP before all your losses. Or work it backwards, starting with the HP needed to push your boat at the speed you want. Before buying a kit of parts based on speed/tonnage claims, see it in use, in person, not on youtube. And know what questions to ask. Talk to cusstomers, too.

There are battery charger/testers designed specifically for matching 18650 and similar small lithium cells. They are not expensive. I suggest you get one, and buy enough of those $1 cells to make a 48v pack for an e-bike. You can get a cheap Chinese 1kw front wheel hub motor kit for less than $200, and convert a cheapie walmart bike in a couple of hours, for a cheap and surprisingly fast electric bike. The expensive part of an ebike is the battery, which you will attempt to make. If your cells are up to the task. Generally you want 48v so 12 or 13 in series, and 20ah, so enough in parallel to make that capacity, and a cheapie 6a 48v ebike charger to fill em up. Probably 12 x 6 or 72 evenly matched cells will get you in the ballpark. If your charger specifies 13S, then 13 series. Don't forget the BMS. Or don't worry about it and just rely on the run like hell emergency procedure, and charge the pack somewhere safe, where it can't burn down stuff. You can internally fuse all inter cell connections, for more safety. Anyway you might be surprised at the actual capacity of those cheap cells and how difficult it is to match them. It can be done and it has been done and it is done all the time, but selecting cheap lithium cells is kinda like the princess said, you sometimes gotta kiss a lot of frogs to find one prince. So get some practical experience with building 18650 packs before you commit to building and using a big one on a boat that will be making long ocean passages far from help. When you have built the battery pack for your boat, and tested it, check back in and tell me that it was cheaper than 8 golf cart batteries.


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## Samson (Jan 23, 2018)

I've never found Optimism to be a problem : )
To be honest I think lead acid batteries are relics of a bygone era and as I mentioned in my first post I intend to use 18650 batteries and I am a stubborn SOB.
I am well aware that li ion batteries burn with the fury of a thousand suns... quite spectacular! I know the risks and I am only risking myself.
I will in two weeks time be flying halfway around the world to buy a boat to live on, I have no time for side projects or crewing for someone else.
If it doesn't work out, I will simply set sail without any motor at all, no biggie. Man Kind has been sailing for millennia with out motors.


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## piotrsko (Dec 9, 2007)

Yup they burn, but you have all the coolant fire suppression you can pump over the side.

There are basically 3 main reasons they flame: over charge, under charge and puncture/ shorting. Avoid those.


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