Those are great numbers.
Below are some earlier numbers but I know I'm doing better now (almost 1mph improvement per 10amp on the low end) - so good to re-run.
Amps Speed (mph)
10 2.6
20 3.2
30 3.9
40 4
50 4.5
60 5.1
70 5.6
80 5.7
90 6.2
100 6.3
110 6.4
All @48V - would be good to publish values normalized to watts for easy comparison to other vessels.
I will run a new set today if conditions cooperate. My boat is heavier, and it's PHRF is a running joke, so I would expect to see 10-20% better speed on the ericson just because of the hull.
It's very good you are paying so much attention to the noise levels. I believe much of the attraction to electric propulsion is aesthetic - noise, smell, simplicity.
-Keith
--- In electricboats@
>
> Test results for the initial run of an Advanced Marine 24 volt BLDC motor in an Ericson 27 (6800lb displacement)
> Conditions: Light wind, slack tide, batteries charged to 13.2v.
> We motored 5 minutes to the San Rafael Channel, and proceeded to make two runs from San Rafael to the Brothers and back.
> Heading, Battery Current, and Speed (GPS)
> 100 degrees,10 amps, 2.6 mph
> 100, 20, 3.5
> 100, 30, 4.1
> 100, 40, 4.5
> 100, 50, 4.7
> 100, 60, 4.9
> 100, 65, 5.0
> 280, 60, 5.2
> 280, 50, 5.1
> 280, 40, 4.8
> 280, 30, 4.5
> 280, 20, 3.9
> 280, 10, 2.8
>
> Notes:
> 1) The motor is bolted hard to the original motor stringers. While this makes the installation strong, it transmits far more motor sound to the fiberglass than anticipated. The motor must be re-mounted using heavy rubber isolation blocks, positioned to provide axial and torsional displacement around the shaft center. In addition, a flex disk will further isolate the shaft from motor output torque ripple. To ensure grounding, a small wiper will contact the prop shaft.
>
> 2) The current/speed relationship was quite satisfactory.
>
> 3) The current limit, originally designed for 105 amps, was reduced to 80 amps peak to ensure controller integrity. The three blade 11 x 11 prop loads the motor/controller to just a little more than the 80 amp limit can handle. The controller then operates in current limit at full throttle until it the internal protection reduces the throttle to limp-home. Once cool, the controller returns to full power, and cycles again. With the current limit increased to 90 amps, this problem should be abated.
>
> 4) The aluminum motor cooling fan resonates additional sound. A nylon fan is now being produced.
>
> 5) The case temperature never exceeded 45C. The internal thermal protection is set at 85C on the controller.
>
> 6) Rough water trials will be conducted when the new motor mounts are constructed.
>
> Arby
>
>
>
>
> ____________
> From: kmannell <kevmann@...
> To: electricboats@
> Sent: Saturday, July 18, 2009 5:09:00 AM
> Subject: [Electric Boats] Re: Direct drive brushless DC motors now available
>
>
>
> Well, we dropped her in the water at 5:20pm 7/16/09. Lots of work was done on the boat including the removal of an Atomic 4 ICE. Please keep in mind that I have never worked on a boat before and am not a sailor. We scraped her down to the gel and painted the topside and resealed the bottom coat, weeks in the San Rafael dockyard with lot's of great people encompassing a wealth of knowledge. We also had some newbie issues with me overseeing the removal of the A4, I missed a bolt and when we pulled it, bent the shaft just a tad. The A4 had a small prop designed for the higher RPM it produced that we replaced with a three bladed 11x11 with a shaft that was 12" longer so we could place the battery pack behind the motor, from the Prop Shop in Richmond.
>
> Long story short, we just did the sea trials and recorded data Arby will be posting soon. I will be doing power testing, as far as I can go, to get a good drain on the 4 70lb, 100ah, AGM batteries in two banks of 24v and will let you know times and distance from a full charge. I am working on our web site and will post the full story there, as soon as possible with lots of pictures and some video. We will keep you informed on changes we make to improve performance or efficiency and follow with data on them.
>
> Kevin Mannell
> Advanced Marine electric Propulsion (.com soon)
> AMeP
>
> --- In electricboats@ yahoogroups. com, postal6@ wrote:
> >
> > Just finished talking with Kevin, who is working with Arby on an Ericson
> > 27. They have changed the prop to a three blade and hopefully will put
> > the boat in the water tomorrow, July 15, 2009. This is the 24v system.
> > Don
> >
>
>
>
>
> [Non-text portions of this message have been removed]
>
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