My project to build an electric boat

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Deddly
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Joined: Fri Dec 21, 2007 4:31 pm
Location: Södermanland, Sweden

My project to build an electric boat

Postby Deddly » Tue Apr 22, 2008 1:35 pm

I'm not sure if this is the right place to post this, I couldn't find forum that applied so I picked "General."

First I'd like to apologize for my recent silence, there's been a lot on here and we've moved house and <INSERT=EXCUSES> and <INSERT=MORE EXCUSES> so...</(MORE) EXCUSES>

So anyway, I have spent some months building something between a raft and a boat. It's a 5 meters long and 3 meters wide catamaran. The hulls are made from polystyrene foam which I've cut/glued/shaped and painted with a special protective coating. The deck is made from the same kind of wood you would normally use to build a veranda. It will eventually have a home-made mast and sails and I'd like to put a motor on it.

I'd really love that motor to be electric, they're so lovely and quiet and, being a boat, I suppose I don't have the same weight concerns as a car builder would have. I know there are a few electric outboards on the market but I've not seen one powerflul enough to shift anything bigger than a canoe, and they are very expensive (cost is a big thing in this project.)

So, I'd like to build one myself. Here's where the fun starts. The most advanced thing I've ever built that's electric powered is a radio control car from a kit. I don't know aything about what motor to choose, what kind of battery is the best option for a boat, etc etc. Can anyone help me here? Here are some things I've noted that I need to think about when choosing equipment:

1) The boat is heavy and it will be in a slow moving river - I need something with a bit of oomph, I want to feel like I'm really getting somewhere, but this is not a speed boat. I suppose something like 5-10 horsepower would be fine.

2) I want to be able to travel for hours on a single charge, running out of power would be a bad thing since the way home is upstream.

3) I can charge the batteries from it's mooring since I can just run an extention lead down there from the shed, so they don't have to be super light and portable...as long as the boat floats... :roll:

4) It doesn't have to be an outboard, it's probably easier to build an inboard motor I imagine.

5) I do have a friend who's an electrician if expertise is needed in the installation.

6) The winter can be as low as -20 degrees celcius here (but not likely to go that low these days, although below zero is very common). I don't know how much of an impact that makes on my options.

Any help would be very much appreciated! As I said, I'm totally new to EV building so...

--
Ed

marktime
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Postby marktime » Tue Apr 22, 2008 2:13 pm

Hi Ed, I can't offer you much in the way of answers or solutions but item 3 is crying out for one of my 'did I really say that out loud' moments.

Since you say you wil be mooring it on the river you might be able to get the water flowing by to turn the prop and recharge the batteries (a tiny bit).

Just thinking out loud

MarkTime
Soft as Graphite, Hard as Diamond, Black as Coal & clear as CO2, It's a Carbon thing!

Deddly
Posts: 31
Joined: Fri Dec 21, 2007 4:31 pm
Location: Södermanland, Sweden

Postby Deddly » Tue Apr 22, 2008 2:51 pm

Since you say you wil be mooring it on the river you might be able to get the water flowing by to turn the prop and recharge the batteries (a tiny bit).


Actually I have considered that, but it is a very slow flowing river...worth a thought though. On the other hand, just upstream is a large sluice gate which has 11 cubic meters or water gushing out of the bottom every second - that is just BEGGING to be harnessed...=o)

Let's get the motor on the boat first though...
--
Ed

Deker
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Location: Borehamwood

Electric Cat

Postby Deker » Sat May 03, 2008 2:09 am

Hi Deddly.

Before you spend too much time and money on your project, I would suggest you do some research on battery performance for use in cold application/s.
Many batteries cannot function well in the mode you wish to use in cold weather.

The Lynch motor is well suited for your application.
They are not cheap, secondhand ones are available.

Try to find an outboard leg with a worn/damaged engine.
An engineering shop or good home based hobby engineer should be able to attach a Lynch motor to an outboard leg.

Do polish the propellor, I found this helps with low powered outboards.

The Lynch 200 mm motor will work from 12 volts, although at 24 volts to 60 volts it is most efficient.

In the cold conditions you may use your boat, personally I would have an ICE generator on board, connected to your battery charger for emergency use to get you upstream.

Is this any help to you ?

Deker

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PHEV
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Location: Peacehaven/Brighton

Postby PHEV » Sat May 03, 2008 2:59 am

Hmm, I'm just about to set too on an outboard conversion myself.
Other choices for motor are the new "Etek-r" and "-RT" motors, or even a Perm 132 is cheaper than a lynch I believe. Cheapest of all is the "mars brushless etek", with the added bonus of no brushes to wear out, though lower power than the above.
If you intend to use the boat in the winter, then plump for LifePo4 type batteries, these suffer far less in the cold than most other types I've found. They are a little pricier, but it will pay off in the long run when they return you a much longer life than just about any other cells.

My conversion will be for a customers yacht, and he tell me he has a device which he can trail out the back whilst sailing, with a prop of some kind that charges his lead acids. He intends to buy more to help charge his batteries on the fly. Could you find a way to "dangle" one of these down the local sluice for some free juice? :roll:
*Mazda MX-5, 300KW peak, 300v 20KW/h lipo pack, Soliton 1000A controller. 1100KG.
*Ducati SS twin Agni 80HP peak.
*Aprilia RS motorcycle, 500A controller, Cedric's AgniMotor, 96v 6kw/h LiPo pack, 130kg, 90mph.
www.jozztek.com

Deddly
Posts: 31
Joined: Fri Dec 21, 2007 4:31 pm
Location: Södermanland, Sweden

Postby Deddly » Mon May 12, 2008 5:05 pm

Thanks for the tips guys! These motors sound interesting, does anyone have a link to a place I can buy them/read up on them? I'm also interested in some kind of chart to compare watts with hp - I have no idea how strong an electric motor I need, but if I was buying an ICE I'd go for somewhere between 4 and 10hp. What's that in watts, roughly?

Batteries...I love the LifePo4 batteries but I think they are going to be way out of my reach - this is a homemade boat on a very low budget - the sails are going to be made from tarpaulin if that gives you an idea... I heard some interesting things about Nickel Iron batteries - almost indestructible. I found a place that has them as a power storage from solar cells, it's been in operation for over 40 years! Does anyone know anything about them? I'm going to have to start off with a smal battery and save up for more capacity in the future I imagine. I don't need a huge range in the begining.

That device for dangling overboard for charging the batteries sounds VERY interesting! In fact, maybe I'll make one :roll: -->off to find out how to make one...


Seriously though, I'll come back to that when the motor's done..

Thanks again for the help so far, keep it up! =o)
--
Ed

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PHEV
Posts: 123
Joined: Wed Mar 26, 2008 5:50 pm
Location: Peacehaven/Brighton

Postby PHEV » Wed May 14, 2008 2:12 am

These guys give good service in my experience, http://www.electricmotorsport.com/store ... _parts.php
750 watts = 1 HP, so 4 hp motor is 3000w, 10HP is 7500 watts.
*Mazda MX-5, 300KW peak, 300v 20KW/h lipo pack, Soliton 1000A controller. 1100KG.
*Ducati SS twin Agni 80HP peak.
*Aprilia RS motorcycle, 500A controller, Cedric's AgniMotor, 96v 6kw/h LiPo pack, 130kg, 90mph.
www.jozztek.com

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MB
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Postby MB » Wed May 14, 2008 1:47 pm

Don't worry too much about using lead acid batteries in winter. The answer is to keep them warm, so make sure they are insulated and then keep them warm either with a heated belt powered by a solar panel or with a simple home-made hot water solar panel.

As a solution its far cheaper than using them thar posh batteries.

The cheapest and best solution would be to get an old broken outboard petrol motor - I scrapped one last year which would have been ideal - and then use that as a base. Brushed motors are easier to set up than brushless, because you don't need such an expensive controller to get them going.

Deddly
Posts: 31
Joined: Fri Dec 21, 2007 4:31 pm
Location: Södermanland, Sweden

Postby Deddly » Mon May 26, 2008 7:16 pm

This is good stuff...I'm still doing a lot of research.

OK I need to clarify something here. Although of course I'd like the lynch motor with a nice set of lithium batteries, that is just not going to happen with my "budget." The two hulls of this boat are made from scrap and the mast and sails will all be done with whatever cheap off-the-shelf/scrap stuff that I can get hold of. I'm one EV wannabe with a low, low income.

I'm on the lookout for thrown away outboards I can use parts from (a shame you scrapped that one, Mike!). I didn't realise that electric motors are so expensive - I mean I can buy an electric power tool with a powerful motor much cheaper than I can buy just a motor for - what's that all about? I guess it's more specialized or something?

So the thing is, I'm not looking for perfection here, I'm looking for something a DIY enthusiast can chuck together from cheapo bits and bobs. That being said, I need help to choose what cheapo bits and bobs to use. I was thinking along the lines of a second-hand starter motor, but it feels like it's maybe not up to the job?

--
Ed

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MB
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Postby MB » Mon May 26, 2008 7:32 pm

Scrapyards and the Bay of E sound like the haunting grounds you ought to be searching.

I picked up a couple of 12-48v 2kW electric motors earlier this year for £35 the pair on eBay, and the smaller 500w-1kW motors are available for sub-£30, you often see outboard motors down at scrapyards.

Will a starter motor do the trick? Probably. And they're cheap to buy. Again, head off to the scrapyard and see what you can find.

As for batteries, back to eBay again for those: you're after some traction batteries or leisure batteries or industrial batteries that have had an untroubled life in an industrial UPS.

I would suggest you can do without a clever controller - you either have an on-off switch or a potentiometer to provide speed control.

Alternatively, you go onto eBay and buy yourself an electric scooter or disability wagon. You'll have the motor, the controller, the batteries and the charger, all in one go.


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