BRUSHLESS OUTBOARD MK2

[Alan]

I showed my brushless outboard in a previous post and have now been modifying it to make it neater and more compact, so here it is:

Another picture showing the motor head close up:

The stainless can is 110mm dia. x 120mm high and was supplied by Ikea.

Here are some numbers which might be useful or interesting, I hope:
Prop speed at 24v 1560 theoretical, 1530 measured.
Motor only load 23.9v 3.0A
Motor and gearbox load 23.7v 5.5A
The numbers do not change with or without the stainless can so there are no eddy current effects.
The motor normally works at 600w to 800w full power so about a fifth of the power is wasted before reaching the prop, which is quite good. Next step is a folding prop for which I have bought some stainless strip but that will have to wait until I finish some proper work; at least I've done something a wee bit boaty!

[Paul H (admin)]

Very interesting. I have an electrical and  electronic engineering degree and would love to know more about the technical details.

I'm a committed greeny and believe solar/wind charged electric propulsion will make internal combustion engines obsolete for small/medium boats.

Paul

[BrianP]

This popped into my Facebook feed this morning. Chap has travelled all over the European rivers with his solar cat

https://m.youtube.com/watch?v=LdJNpbHLvFI

[simplesimon]

Now, why did I think "moggie lying in the sun"!

[Alan]

"would love to know more about the technical details."

Not much electrical detail, Paul. The motor and speed controller are hobby grade designed for large model aeroplanes, and shown in another thread on the general discussion board.

Plenty of mechanical bodgery requiring a lathe, such as a motor mounting plate with o-ring groove to seal against the stainless can; a pin drive shaft connector which connects to the shortened vertical shaft without fasteners, as the shortened shaft is well below the top of the casting; making a matching slot in the annealed hard stainless shaft; and a connector for the two half shafts in the gearbox leg - they are normally connected by a wrap spring to transmit torque in only one direction, but I wanted a reverse facility.
The last point took days of work and failed after I removed too much metal trying to make it fit in the available space. I solved the problem with two hose clips!

For an order of magnitude less energy use see Jeremy's "electric boat thread" on the Endless Sphere forum (mainly about electric bikes). I'll be copying his method to make a more efficient folding prop.