4-5hp electric outboard

[Pompel79]

Hi
I have plans to put an electric motor in a 6hp outboard motor.
Is there anyone who can help me with what kind of motor and speed controller to choose?
The engine will be used by my 6 year old son on a small 9 feet inflatable boat. The engine should provide about 4-5hp
Will any of these engines fit?

http://hobbyking.com/hobbyking/store/__17987__Turnigy_RotoMax_50cc_Size_Brushless_Outrunner_Motor.html

http://alienpowersystem.com/shop/80mm/c80110-sensored-outrunner-brushless-motor-80kv-6000w-2/

http://www.ebay.com/itm/BRUSHLESS-MID-AXIAL-MOTOR-48V-1500W-CONTROLLER-E-SCOOTER-E-BIKE-QUAD-BIKE-CAR-/201060585451?pt=LH_DefaultDomain_0&hash=item2ed0250feb


Hope someone can help me

 

[n3glv]

First of lets dicuss what watts and hosrepower mean.
One electrical horsepower is 746 watts.
HOWEVER
Electric motors are not reciprocating power obtained by a pulse of energy from
a fuel explosion, or need to take powerless strokes to intake and exhaust.
They make continous torque. 360 degrees.
If you want equiv performance to a 6hp gasoline motor, my guess is that a 1500w
electric with the right rpm spec may work fine.
You could also maybe run a pair of them with a chain drive.
You'll need a PWM controller that is rated for the amps and volts for the motor.
Volts times Amps=watts
In general, volts will get you speed and amps will get you torque.
If you use anything other than lead acid or deep cycle batteries you'll also need a BMS
Battery Management System, to prevent damage on discharge or charge..

Hope this helps.

 

[Wheazel]

I would start off by looking at some info.
I googled prop rpm and it seems to be in the 3000-3500 rpm at full throttle for most boatdrives. Naturally giant ships will have props spinning much slower but thats irrelevant.
https://answers.yahoo.com/question/index?qid=20101104203006AASboRy

Then, what battery do you plan to use?
Will be much easier to know what motor kv you need if you have a somewhat clear picture of this.
Also, will there be gearing between the motorshaft and the prop, or is it direct drive?

 

[agniusm]

I started on full custom outboard but ended up breaking the shaft. I have read that slower larger prop is a lot more efficient which is important using electric drive. I dont remember the site but if you would look for diy prop should be easy to find.