I recently took ownership of a 1983 Duffy 18’ boat, it is a fiberglass displacement hull cabin cruiser that is pure electric, inboard drive 2.5hp GE 36VDC series wound brushed motor that gets it to 3 and 5 mph on low and high. The transmission is a set of V belts at 2.75:1, so the motor spins at 2000rpm and the prop shaft at 720rpm.
I need to replace the motor and need some help selecting a replacement. I’m changing the boat to 48VDC and not really interested in making it faster, but more efficient. I was looking at Golden Motor 3kw/5kw and Motenergy, Looks like Golden is axial flux and I am pretty sure I want a radial flux motor with better low RPM torque.
I’m not sure how to use the motor performance curves to select the right unit for my boat, I don’t understand how variable speed drive interacts with a fixed voltage dynometer plot. The propeller is 7" with an unknown but visibly “tall” pitch, larger than what you would find on a small outboard.
Trying to stay under $2k and would like it to be quiet and efficient, appreciate any advice. Will consider liquid cooled.
D & D Motors could also give you guidance. Unless totally trashed your present motor can be rebuilt for under $100 in parts. New GE motor should be in +/_$1000 range,
The 36 volt setup in a Duffy is a good fit for performance and range.
However if your going to do it. You will also have to upgrade the controller. to a modern electronic unit like the Curtis or GE.
I would strongly consider Lithium if your going to all this trouble,
Lots of expertise on this forum that can be adapted to your boat.
The reason I am looking into a new motor, is that I have several options for a more powerful, quieter and more efficient motor that include a controller, for less than what Duffy offered an “Infraspeed” upgrade for. I don’t actually have a motor malfunction, but I do have a bad contact in my drive control lever which causes it to divide my battery bank improperly. The motor, on low speed generates a redonkulous amount of heat, although I do need to add some ventilation.
Then I assumed correctly that you have the series parallel 2 speed operation unit.
You could replace your present setup with a Curtis Controller and A GE, D&D, AMD etc motor or keep your present motor.
If your handy you could scrounge up used golf cart control components that will handle up to 7 HP rather inexpensively.
FSIP could probably work you up a package. Do you have room for 2 more batteries? Or you could switch out to 8 volt units. Lithium would be better and lighter. How much did Duffy want for their control?
I recently took ownership of a 1983 Duffy 18’ boat, it is a fiberglass displacement hull cabin cruiser that is pure electric, inboard drive 2.5hp GE 36VDC series wound brushed motor that gets it to 3 and 5 mph on low and high. The transmission is a set of V belts at 2.75:1, so the motor spins at 2000rpm and the prop shaft at 720rpm.
I need to replace the motor and need some help selecting a replacement. I’m changing the boat to 48VDC and not really interested in making it faster, but more efficient. I was looking at Golden Motor 3kw/5kw and Motenergy, Looks like Golden is axial flux and I am pretty sure I want a radial flux motor with better low RPM torque.
I’m not sure how to use the motor performance curves to select the right unit for my boat, I don’t understand how variable speed drive interacts with a fixed voltage dynometer plot. The propeller is 7" with an unknown but visibly “tall” pitch, larger than what you would find on a small outboard.
Trying to stay under $2k and would like it to be quiet and efficient, appreciate any advice. Will consider liquid cooled.[/quote]
Go to thunderstruck-ev dot com and look up their 5KW Brushless Sailboat Kit. The kit can go 36 or 48v.
Thanks all. Thunderstruck does have neat stuff. I am strongly considering both Thunderstruck’s Motenergy/Sevcon kit, and Golden Motors’ 3 and 5kW kits. Golden motor is certainly cheaper, especially when you look at programming kits and software.