Hi James,
Whilst not one of your systems. Here's my 'power up' or bollard pull/zero thrust screenshot at the battery from my Victron Color Control GX.
I don't trust my clamp meter measuring at the motor or the controller programmer readouts. My voltmeter I trust at the motor. Suffice to say once I do a system efficiency measurement/calculation at the shaft I seem to be around 80 to 84% efficiency. Subject to load I estimate with the two blade I'm over the 50% overall system efficiency, although the last ounce of efficiency becomes less of an issue at low power outputs of less than 1,000 Watts say, which is where I cruise most of the time which gives around 4 knots.
My system is a D135 Lynch direct drive with 2 x 12.8 Lithium 200Ah Lithiums in series, so 26.6V nominal. PGDT/Curtiss-Wright controller at 100% demand and motor 95.5% on. This is a 12 x 10 two blade K11 prop ref:
Propellers Radice: www.propellersradice.com - Eliche Radice: www.elicheradice.com
At the other extreme I tested using a 12 x 14 3 blade E11 prop ref:
Propellers Radice: www.propellersradice.com - Eliche Radice: www.elicheradice.com
I pull about 115 Amps at full throttle bollard pull with that, so 3kW as opposed to 2 kW. The happy medium is probably a 3 blade 12 x 10 or 11 for my boat, of that off the shelf prop make, to ensure my cruise speed is at the highest motor efficiency for the cruise voltage/current balance measured at the motor.
John
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