Last weekend I realized that it had been about 2 years since my last performance test, and I wondered if anything had changed over time. I was at the marina on Easter morning and the conditions appeared to be ideal for another performance test. I ran through the same process listed below in about 100 minutes, covering a little over 7nm in total.
Here's this weeks results:
497W = 3.1kts
1000W = 4.0kts
1500W = 4.5kts
2500W = 5.2kts
3975W = 5.7kts
5000W = 5.9kts
So there have been pretty minor changes, well within testing errors. Like before, the max winding temp was 72C and that temperature had dropped to 53C by the end of the last slow speed pass. 2 years later, the drive, prop, hull, batteries, etc. seem to delivering consistent performance.
If I average the three different testing sessions, the numbers look like this...
Here's the overall average results:
499W = 3.0kts
1000W = 3.9kts
1500W = 4.4kts
2470W = 5.0kts
3935W = 5.7kts
5115W = 5.9kts
This data collectively represents more than 3nm at each speed, in calm conditions, in multiple directions.
On another note, I did a full throttle run at the dock. Average amp draw was 158.8A DC at 47.24V or 7.5kW! Compare that to the 5.1kW noted above at full throttle in open water. Since I was starting with 80Ah already used of my 128Ah of usable capacity, the 160A load was rapidly draining my battery pack. After more than 5 minutes at full throttle, the motor windings had climbed to 85C, well under the manufacturer's rated limit of 150C, although the temp had not stabilized yet. I decided to stop the experiment as I quickly approached having only 30% of my usable capacity left and I didn't have too much time to get some electrons back into the pack before I had to leave. Perhaps I can do this again with a fully charged pack to see where the ME0913 motor temps will stabilize while pulling 7.5kW in the bilge of my boat. In spite of what some of the component vendors might say, I'm pretty sure that running that motor in boat at 10.5kW will cause it to overheat in relatively short order. I appreciate that my vendor conservatively rated my entire drive system, I'm sure that it will continue to perform well for many years.
Anyway, I collected the data and I thought that some people here might find it interesting...
Fair winds and smooth seas,
Eric
1964 Bermuda 30 ketch, 5.5kW Propulsion Marine drive, 8kWh lithium batteries
Marina del Rey, CA
Here's this weeks results:
497W = 3.1kts
1000W = 4.0kts
1500W = 4.5kts
2500W = 5.2kts
3975W = 5.7kts
5000W = 5.9kts
So there have been pretty minor changes, well within testing errors. Like before, the max winding temp was 72C and that temperature had dropped to 53C by the end of the last slow speed pass. 2 years later, the drive, prop, hull, batteries, etc. seem to delivering consistent performance.
If I average the three different testing sessions, the numbers look like this...
Here's the overall average results:
499W = 3.0kts
1000W = 3.9kts
1500W = 4.4kts
2470W = 5.0kts
3935W = 5.7kts
5115W = 5.9kts
This data collectively represents more than 3nm at each speed, in calm conditions, in multiple directions.
On another note, I did a full throttle run at the dock. Average amp draw was 158.8A DC at 47.24V or 7.5kW! Compare that to the 5.1kW noted above at full throttle in open water. Since I was starting with 80Ah already used of my 128Ah of usable capacity, the 160A load was rapidly draining my battery pack. After more than 5 minutes at full throttle, the motor windings had climbed to 85C, well under the manufacturer's rated limit of 150C, although the temp had not stabilized yet. I decided to stop the experiment as I quickly approached having only 30% of my usable capacity left and I didn't have too much time to get some electrons back into the pack before I had to leave. Perhaps I can do this again with a fully charged pack to see where the ME0913 motor temps will stabilize while pulling 7.5kW in the bilge of my boat. In spite of what some of the component vendors might say, I'm pretty sure that running that motor in boat at 10.5kW will cause it to overheat in relatively short order. I appreciate that my vendor conservatively rated my entire drive system, I'm sure that it will continue to perform well for many years.
Anyway, I collected the data and I thought that some people here might find it interesting...
Fair winds and smooth seas,
Eric
1964 Bermuda 30 ketch, 5.5kW Propulsion Marine drive, 8kWh lithium batteries
Marina del Rey, CA
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