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Old 09-16-2009 | 03:10 PM
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Zero369
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Default Are These Numbers Correct

I been noticing that on BL motors, amps are fixed numbers and the watts change or vice versa. So if was different number on some motors then I figure they can be changed, yeah? So lets use the Velineon for my example...

Traxxas Velineon 3500
RPM/volt: 3500 (10-turn)
Max RMP: 50,000
Current Ratings: 65A constant / 100A peak/burst
Lipo
25,900 RPM on 2s Lipo 7.4v - 65 Amps @ 481 Watts
38,850 RPM on 3s Lipo 11.1v - 65 Amps @ 721.5 Watts 481/11.1v=43.3


Fixed numbers on the amps, but the watts are different numbers. If I take the amp value 481 Watts from the 7.4v and divide that with 11.1v it gives me 43.3 Amps (481/11.1v=43.3).

*25,900 RPM on 2s Lipo 7.4v - 65 Amps @ 481 Watts
**38,850 RPM on 3s Lipo 11.1v - ??? 43 Amps @ 481 Watts ???

* The 7.4 stays the same and give you clear flat calculation... 65 Amps @ 481 Watts
** The 11.1v amps change and using a higher voltage does give you less amps, but the watts number stays the same as it is on a 7.4v. 11.1v should give you more watts right?

Maybe there are two ways of looking at numbers, I dunno; but on other motors the numbers are different.

Novak Ballistic Racing Brushless Motor 8.5T
Watts: 280
kV: 5000 RPM/volt (unloaded)
Lipo
37,000 RPM on 2s Lipo 7.4v - 37.8 Amps @ 280 Watts - 37.8 Amps X 7.4 = 280 Watts
55,500 RPM on 3s Lipo 11.1v - 25.2 Amps @ 280 Watts - 37.8 Amps x 11.1v = 420 Watts (419.58)

Does it really matter how the numbers are read? And did I explain this right at all?

Ray