T-Pain Is On A Boat: Re: [Electric Boats] Why gear reduction?

Thursday, February 25, 2016

Re: [Electric Boats] Why gear reduction?

Mike,

My question to you and James is how can a professional geared system from ElectroProp, Electric Yacht, or Thoosa as you suggest, either with 36V or 48V system battery voltages be lighter than a direct drive 24V or 36 V system such as professional systems from those below whose motors all weigh around 12Kg? Indeed don't Thoosa use these type of motors? To compare weight all systems should use the same type and Ah of batteries? In fact isn't it reasonable to compare all up system weight too? Direct drive from other professional vendors:

http://greenstarmarine.se/en/

or

http://www.bellmarine.nl/ (Mastervolt partner)

English pricelist and system here: http://www.bellmarine.nl/files/Price%20List%20september2015%20Bellmarine%20export%20.pdf

or

http://lynchmotors.co.uk/

Thrust management is built into these systems above within the motor subject to ones requirements for that. Heat management is not an issue in the systems subject to the power required. I think what you and James need to say is at what power you require gearing, improved thrust management and improved heat management for higher powered systems?

I note you also refer to Elco. They make this statement "Why is our electric motor the most efficient?"

on this page:

http://www.elcomotoryachts.com/electric-101.shtml

They say "The efficiency on even a good D/C motor is seldom above 80-85 percent efficient which sounds pretty good. Now take an A/C motor, especially a 3 phase A/C induction motor there are no brushes, no commutator, there is no rotating, winding and the efficiency of a good motor starts at the high 80 percentile and goes up into the low 90 percentile."

on this page:

http://www.elcomotoryachts.com/?testimonial=ac-electric-motor-compared-to-a-dc-motor

But my motor is a Lynch, DC and brushed and at my power requirements is around 88% efficient. It can be 93% subject to system design it seems.

Personally all these statements from professional vendors makes me (the public) confused. I don't know who to believe anymore! I'm a DIY'er and would like to know why there seems to be such differing claims made amongst professional vendors?

John R.