From: Michael Ryan mryanqld@gmail.com [electricboats] <electricboats@yahoogroups.com>
To: electricboats@yahoogroups.com
Sent: Sun, 01 Apr 2018 19:21:39 -0400 (EDT)
Subject: Re: [Electric Boats] Converting from diesel power
A 10kw
motor is more powerful of course at higher voltages and current than the 5kw
motor but it may not use any more current to produce my more modest power requirements. This means for a given propeller speed the 10KW motor should not consume much more power than the 5kw motor. A larger motor will obviously dissipate heat
better and have a much longer service life. Disadvantages of the bigger motor
are the increased cost of the motor/ controller, some extra weight and a
slightly bigger space footprint required. The ME1115 motor supplied by Thunderstruck was fitted in the Zero motor cycles several years ago and produced over 50hp at 102 volts. I will running 48 volts way under the maximum voltage for this motor. The Sevcon controller supplied with the 10kw kit is rated at 550 amps which again is well under my expected maximum current draw
An interesting
specification of these Motoenergy motors is their volt/RPM constant. This is a nominal number
that helps dictates an optimum operating speed. The ME1305 is wound with 20
turns of wire per phase and the ME1115 with 28 turns of wire per phase. But the
supplier information states that both motors are designed to turn at a given
voltage with the volt/RPM constant of 50. At 48v both motors, maximum speed
should be around 2400RPM. I suspect that ME1115 may have a higher constant of
65 which is 3100 RPM. I will start somewhere around 2.5:1 reduction to get my propeller shaft maximum of 1000 RPM.
To sum up I believe the extra $400 or so dollars for the 10kw kit was worth it.
Kim,I would be inclined to suggest the Torqeedo 4R Electric Outboard, rated at 10hp. I would think it would push your 16' tug to 4mph just fine. However - the problem would be that you would have to find a way to mount an outboard - which would probably mean you'd have to make a motor well in the bottom of the boat.The $5000+ plug and play systems might be overkill for what you need? Though by the time you put everything together, it does get pricey.Good luck!John
On Sunday, April 1, 2018, 2:50:04 PM CDT, KIM GYE kimgye@shaw.ca [electricboats] <electricboats@yahoogroups.com> wrote:Hello. I am a new member and would welcome advice regarding converting my boat (a home built 16' tug) from 25hp diesel to electric drive. I am having trouble figuring out what size motor I need as I don't have displacement info on this boat etc. She weighs about 3000lbs. Beam at waterline is 7'. Length at waterline is 16'. Submerged depth is 2' not including keel/rudder. The motor is old and probably would honestly rate at 20 hp. My hull speed is 4 knots max and I attain that using only 1200 rpm. Motor max rpm under load is about 2200 .
I have looked at plug and play systems from the bigger companies but they are $5500 us and up which is above my budget for a drive system before batteries. I have found two companies that have sail boat systems for about $1600 us (Thunderstruck and Electricmotorsport) they are both in California. Does anyone have any advice or can point me in the right direction? Thanks in advance.
Kim
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Posted by: DAN HENNIS <dhennis@centurytel.net>
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