Homemade Electric Outboard?

[IRMC000]

Does anyone have any info on making your own electric outboard?
Designs? Propeller revs? etc.
Thanks

[cormorant]

Do a google as there is a whole racing class in the USA for electrics and there is now production model electric outboards up to about 6hp. Look up electric boats or eco boats etc. There is a brand sold here in AUS that even has a Lithiun battery and a foldable leg called the traveler from memory that would be great for the tender if it didn't cost so much. You need some serious weight in batteries but no engine maintainance does look attaracive.


Edit

A couple of intersting sites

http://www.seattleoutboard.org/electric.html

www.torqeedo.com

http://www.ecoboats.com.au/

And look up Thoosa ?? inboard electric motors , small and very powerful

[Mrs Ronnie H]

Hi
Saw an article-- think in the latest BNB where yo can turn your Whipper snipper into an electric motor for your boat????????????????????
May be worth checking this out for interest sake if nothing else.

Mrs Ronnie

[foxx510]

I think that unless you have access to free parts and equipment then you won't save any money by building your own. That's not to say you shouldn't do it for the fun of it!

[cormorant]

Effecient high revving 12 volt motors are very expensive and you need the high revs if you are going through an existing 4hp gearbox as you are limited by props and ratio.

I have been in a boat with a Thoosa (spelling) inboard and it was impressive for a displacemet boat and the battery weight low in the keel area made it a very stable boat. The response and quietness was eerie.

[IRMC000]

I have access to batteries and a range of motors - it's the specifications I need to get me in the ballpark. Can someone post the following for me please for their electric motor:
Prop revs?
Prop diameter?
Ampere draw at full throttle?
Thanks

[foxx510]

http://www.electricmotor.net.au/index.html has some info, not super specific and technical but maybe helpful.

The idea of an electric boat really appeals to me. Quiet and clean. Just need some good new battery technology to come along. Lets hope the oil runs out soon ;-)

[oldboot]

I was amusing myself with the prospect a while ago.

After some looking and fiddling, I came to the conclusion that it was far cheaper to buy an off the shelf electric outboard....


however.

I considered that many of the factors that vex propellor selection for petrol motors were less critical with an electric motor.

Of course you do want the prop to be able to spin at a speed where the motor generates maximum power.....use of similar tables from similar sized outboard motors wolud give some indications..

The biggest problem is the storage of energy......batteries simply can not compete with burning something.

the second problem is the large ammounts of current involved....the more power you intend to use the higher voltage you need to run to keep the current at a managable level.

Consider there are aproximately 720 watts to the horespower...at 12 volts that is 60 amps...... factor in about 60% efficiency.

so for a 15HP output you need to put in 25HP of electrical energy which equals about 18000 watts which would be 75 amps at 240 volts ot 150 amps at 120 volts.

there are traction motors available of about that size but they are not cheap.

so in a 120 volt system for a run time of 4 hours ( assuming a 50% cycle) 1200AH battery at about 3.5KG per 100amp hour / volt... the battery would weigh about 5 tonnes.

then we have to consider the controll system we need to build to control the speed of the motor....you could buy an off the shelf controll system but it wont be cheap.

The idea of an electric outboard is appelaing but at this point them practicality and the expense is a real problem.

the nearest thing to being practical is an off the shelf trolling motor or two an couple (or 4) of 100AH batteries and a petrol powered generator to charge them....a hybred.
and that wont be all that fast.

So........wind is looking like a real alternative to propelling a fishing boat.

You could build a puddle duck racer including sails for about $300 and stick a lecky on it.

just some thaughts. cheers

[garman1]

Well it sounds that rather than rolling the side clears up on a nice day, might have to make a small mast for each side of the bimini and stick the clears up in the breeze and rename the boat "wild wheat"(it certainly won't be a racer)................... now to search for a winged keel !!!!!!!

[oldboot]

For some fishing I think wind power real has some merit, particularly when combined with a standard electric outboard and or a bit of muscle power.

check out these links.

www.mit.edu/people/robot/lepalepa/index.html

http://koti.kapsi.fi/hvartial/

http://homepage.mac.com/peterhyndman/Sites/PDRinfo/

cheers

[oldboot]

For those still interested in electric power, have a look at this site for a bit of a reality check on traction motors and prices.

The two issues that make electric power ( or any power) on a boat is the requirement for constant high power input to keep a boat traveling...... boats do not coast....so the 6 odd HP and bank of batteries that would get a golf cart with 2 people aboard traveling very nicely all day, would struggle to push anything bigger than 10 footer and you would get an hour or so of range.....and the batteries would weigh about what two people would (probably more).

www.evmotors.com.au

cheers