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15kW electric motor for Sailing Catamaran

12151 Views 16 Replies 11 Participants Last post by  popobowa

Looking for advice on a 15kW 48V electric motor to fit to a Yanmar SD25 sail drive (new model of the SD20).

Application is an under construction 52' sailing catamaran.

Some broad boat parameters:

Ocean going world cruising catamaran – composite epoxy structure.
L 52’, Draft 2’ Weight approx. 8500kg / 19,000lb
Full electric propulsion, galley and other services including hot water.
Motors retractable: 2 x 15kw 48v + regen
Battery bank: circa 16kw 48v
House loads: 24V DC – Estimated peak approx. 3kw
Solar: circa 3kW.
16kW 48v DC gen set.

The plan is to fit motor to a Yanmar sail drive SD25 and complete unit be retractable. This involves a wet lower tube and a watertight inner tube with hull closure plate below the prop – motor and sail drive leg fitted to this at their join. We should be able to couple motor shaft to SD25 upper gear box shaft with a coupler and bolt units together without too many modifications. Be great to hear of others experience with this.

We are trying to limit motor voltage to 48V – makes batteries & solar easier plus ability to share bank via DC:DC converters & battery for house loads at 24V.

The boat will be light and shallow draft = easily driven. A similar 62’ catamaran was fitted with 2 x OV SD15s and achieved over 9 knots in flat water so we believe 12 to 15kW motors will be adequate.

According to Vic Prop boat specs, twin 12kW (16hp) motors with RPM max of 2200 (2:1 gear reduction on SD25 so prop speed 1100 max.) & 3 blade 15" x 13" prop will yield a top speed of 8.92 kts which is fine.

We have looked at turn-key offerings from Bell marine, Oceanvolt & Electric yachts but none tick all our boxes so would like to have a crack at customizing our own solution.

Some motor options Ive stumbled across include:
1. Motenergy ME1302 or ME1616 Liquid cooled
2. Parker GVM210-100-DPW
3. Go cart or Elec motorcycle motors: Revolt, Zero, ???

Bearing in mind 48V supply and max RPM of around 2400, be grateful to get your thoughts on best motor and associated controller and any tips or constructive suggestions for our project.

Thanks RC
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The peak current specs on the motors are just for indication of capability--they could operate at this extreme current for a short time (5-10 seconds) without damage.

The motor controller (aka drive inverter, buck-boost converter, etc) would be configured to limit the current (torque) for your application.

Electric golf carts come to mind with low voltage motors in the 48V range. a quick search found some, but they are series DC motors with brushes;

i would want a brushless 3-phase motor if possible, such as PM or AC. Have you seen these:

Looks like an interesting and fun project, post up some pictures of your boat.
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