Castle 1515 Actual Kv

[NeverEnuff]

What is the actual measured Kv for a Castle 1515 1Y motor? How about a Neu 1515 1Y? I measured my Castle 1515 1Y to be 2350 rpm/volt. Just wondering if this sounds correct? I used the data log from my Castle ESC and also verified it with my Snapon Photo tach. Thanks

[StevenBryant]

My castle 1515 has 2200kv on the box


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[Fluid]

The actual Kv will vary depending on the load and voltage. The 2200 on the box is an approximation to guide the consumer in his choice of motors



..

[zooma]

What is the actual measured Kv for a Castle 1515 1Y motor? How about a Neu 1515 1Y? I measured my Castle 1515 1Y to be 2350 rpm/volt. Just wondering if this sounds correct? I used the data log from my Castle ESC and also verified it with my Snapon Photo tach. Thanks

Could you explain how you are getting kv readings or calculations. Thanks.

[NeverEnuff]

I connected a 2s battery and ran the motor no load at full throttle for a few seconds, after downloading the data log from my Castle ESC and looking at the data it was 16653 rpm at 7.0 volts = 2379 Kv. Next I did another run holding my Snap-On photo tach to the end of the motor shaft to verify the rpm reading and I got 16,100 rpm from the photo tach and looking at the data log the voltage was about 6.9 volts for a 2333 kv. Fluid, thanks for the response, I might repeat the test with 3s to see how much it changes. I don't know if I would want to go full throttle/no load with any more voltage than 3s.

See attached data logs
Castle 1515 1Y kv test.jpgCastle 1515 1Y Photo Tach Kv Test.jpg

[zooma]

Ah-ha. Now, I am going to try that with my Swordfish logging ESC. What do you put onto the shaft for the photo tach to read? I am also an airplane guy, so I have used a suitable coupler and popsicle stick.

I have one of those HobbyKing kv meters, and it's off by a lot (and I do verify the number of poles).

Thanks a lot.

[Brushless55]

Interested to see how more testing like this goes...

[NeverEnuff]

I have an older version of one of these:
Photo Tach.jpg
Then I used the cone attachment and pressed it up against the end of the motor shaft.

[kfxguy]

I've tested a few castle 1515's with my kv tester and they were almost dead on 2200kv (2222kv comes to mind).

[Brushless55]

I've tested a few castle 1515's with my kv tester and they were almost dead on 2200kv (2222kv comes to mind).

That's good to know..

[NeverEnuff]

So I reran the test on 2s, 3s, and 4s. The kv does go down as voltage increased. Here are the results from that test. (This is no load on the bench)

2s = 2373 Kv
3s = 2347 Kv
4s = 2322 Kv

[Fluid]

Testing at zero load tells you little about the motor's performance. What we care about is the Kv under load.....unless we don't run our boats in water.

An example is Neu (and many others) who obtain their Kv unloaded. OTOH Lehner tests their motors for Kv under load. If you choose a Neu and a Lehner both with the same listed Kv, your boat with the Neu will be a lot slower given the same prop.

Data logging on the water comparing the actual pack voltage to the motor rpm - at the same time - tells you the true Kv.


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[NeverEnuff]

I figured that I would update this thread after running my JAE FE 21.

Data from Castle ESC data log and speed from Eagle Tree GPS data log.

#Cell Voltage Current Watts RPM KV MPH
4s 13.3 125 1664 26940 2025 68
5s 16.0 158 2534 32254 2015 82
6s 20.2 194 3888 35243 1744 91

Castle 1515 1Y, Castle Converted Mamba XL2, Revo427 4800 batteries, 1817-17-45 prop

You can see the motor on 6s did not like the 1817-17-45 prop. I'm sure the full size turn fin and rudder are not helping at 91 mph.

[kfxguy]

I figured that I would update this thread after running my JAE FE 21.

Data from Castle ESC data log and speed from Eagle Tree GPS data log.

#Cell Voltage Current Watts RPM KV MPH
4s 13.3 125 1664 26940 2025 68
5s 16.0 158 2534 32254 2015 82
6s 20.2 194 3888 35243 1744 91

Castle 1515 1Y, Castle Converted Mamba XL2, Revo427 4800 batteries, 1817-17-45 prop

You can see the motor on 6s did not like the 1817-17-45 prop. I'm sure the full size turn fin and rudder are not helping at 91 mph.

I bet it would go faster with a 1815-17-45 probably with every voltage setup. The 1817 is ALOT of prop for that motor.

[NeverEnuff]

My Bad. I had a typo on the prop. It actually was a 1816-17-45.