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12.5KW Brushless Sailboat Kit

12.5KW SB
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Convert your 12-33 HP diesel engine to clean, quiet electric. Eliminate noxious diesel fumes and the frustration of filling up at the pump with the 12.5KW Brushless Kit featuring a Motenergy brushless motor and a 72V 350 Amp Sevcon Gen-4 Controller that can produce up to 12.5HP continuous and 33HP peak!  Enjoy your sailboat to the fullest, with a silent drive and truly fresh air.

We've supplied our electric drive systems for sailboats up to 30 ft. and 15,000 lbs. displacement, achieving hull speed. All our systems have reverse on-the-fly and contactor disable features. "Brushless" means that the motor does not have brushes that will wear out over time, nor will it be a dangerous source of ignition for on-board gas appliances. Larger boats may require a higher power AC or brushless motor. In the U.S. and Canada, brushed motors are only legal for marine use if onboard appliances and accessories use kerosene or diesel (not propane or gasoline) due to the potential for internal motor arcing.

With Sevcon's Gen4 controller, no reversing contactors are needed. Additionally, the Gen-4 controller has a regen feature than can allow current to be put back into the batteries from the spinning prop while under sail. This does depend on your sailing speed, prop design, and may not be possible in all applications, but is an adored feature for those who are able to utilize it.

gear reduction is not always necessary, and largely depends on the size, efficiency, prop style, and desired speed of your vessel. However, due to the high RPM of the Motenergy Brushless motor, we recommend you consider a gear reduction rather than direct-drive to improve efficiency, provide proper torque, cooling, and help prevent cavitation. Typical reduction is around 2:1, but this ratio will depend on the required prop RPM needed to reach hull speed. Ideal reduction will enable the motor to spin your prop at the hull speed RPM of your prop when the motor is spinning at its max RPM. This number can be calculated using the 50 RPM / Volt constant:

72 Volts * 50 RPM / Volt ~ 3600 rpm max

If you choose not to use a gear reduction, it's important to install a thrust bearing somewhere in line with the prop shaft, as most motors are not rated for axial/thrust loads on the shaft. Also note that a heatsink for the Sevcon controller is recommended by the manufacturer.

Kit includes:

  • Motenergy ME1306 Dual-Stator Brushless Motor
  • Controller: 72V Sevcon Gen-350Amp, programmable, with regen. 
  • Throttle (additional cost)- your choice of: 
    • PB-8 throttle with Fwd/Rev switch 
    • ET-134 directional throttle. For harsh environments we recommend the ET-134 as the most robust option. 
  • Tyco High-Quality Sealed Contactor
  • Key Switch
  • Fuses
  • Every kit is individually bench tested
  • Complete wire harness with 10ft key and throttle cable lengths
  • Wiring instructions

Helpful links:

Check out our instructional wiring video!

You may also be interested in the Sevcon Clearview display!

Those of you that are still in the "research phase" of your conversion should visit one of the electric boats discussion groups and talk to others who are doing or have already done electric conversions.

Gen4 12KW Sailboat Kit Wiring Diagram - for Fw/Rev Switch Option

Gen4 12KW Sailboat Kit Wiring Diagram - for Curtis ET throttles

Gen4 Sailboat Kit Installation Instructions

E-Boat Modeling Spreadsheet (.xls) *Use this to calculate your power needs!*

E-Boat Modeling Spreadsheet Manual (.doc)

Vicprop Calculator



We purchased this kit to power an air conditioner compressor for a full sized Cab on a Railway Locomotive. Plug and play connections made installing it simple. Nice package!
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