Electric boat motors

[outdoordan]

Any DC motor wizards out there?

Got a small boat. 21', displacement hull. Top speed about 6 knots. Has a 10hp two cylinder volvo diesel in it at the moment but considering ripping the lot out and fitting an electric drive.

thinking 72v 4.5kw or similar. half a dozen deep cycle batteries and various charging options.

would be grateful for advice/wisdom.

thx

Dan

 

[Shayne]

Investigating milkfloats found me this Electric Boat set up, EV car Project, Motor, Controller, Batterys, all you need | eBay - [Leaving Land Cruiser Club]

 

[outdoordan]

Yeah. I saw this Shayne. Interesting.

 

[IRLGW]

I think you use DC power but concert it to run an AC motor. Probably need a delta wired/wound setup for control. Tbh it ends up freggin expensive by the time you buy all your shunts, controls, wire up your bank. If you use lead acid then you only have a 40-50% discharge cycle. With such torque available you can fit an oversize prop possibly and go for ultra low rpm. I think forklift motors have a good strong set of windings and may be AC. For a project it could be fun but I don't think cost effective but depends on what you have available. I thought if I ever went down that route then maybe a hybrid setup to a hydraulic motor might be a good compromise. Yes some powertrain loss and inefficiencies but you would always have a combustion power source on standby. Just 2cents

 

[Shayne]

I'm thinking 10hp 6 knots it can't be heavy so would a cement mixer motor achieve the same ? . Couple it to something like this

Reconditioned Gearbox Technodrive TMC 40 - Drinkwaard - [Leaving Land Cruiser Club]

Which are usually configured 2 to 1 reduction but could probably work to multiply instead . Gearbox means forward and astern are mechanical .

And yeah a compact generator beats batteries all day every day .