X-File: Understanding VESC: the difference between "battery amps" and "motor amps"
Ackmaniac, post:274, topic:15995, full:true Wrote:There is a little clip from the Simpson which fits to the situation here.

@Ackmaniac There is a little clip which fits to the situation here:

[Image: 48-200-200-1.png]
[Image: 48-200-200-2.png]





",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/275,2017-02-01 16:52:06 UTC
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Ackmaniac, post:274, topic:15995, full:true Wrote:There is a little clip from the Simpson which fits to the situation here.

@Ackmaniac so where's that proof that 10/150/160 batt/motor/absolute is harmful to VESC's??

@hexakopter

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/276,2017-02-01 17:02:36 UTC
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Ackmaniac, post:274, topic:15995, full:true Wrote:There is a little clip from the Simpson which fits to the situation here.

@Ackmaniac

@ 8 minutes 28 seconds in:





",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/277,2017-02-02 00:39:10 UTC
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A question was brought up in the "Is my math right?!" thread relating to Understanding VESC: software.

This resulted in some new formulas which seem to enable prediction in advance of all or almost all "motor states."

The question was basically:

1440 W electrical @ %95 duty cycle = xxxx.xxrpm

It turns out you apparently can easily calculate the exact RPM for any W electrical and % duty cycle.

^If you know any 2 of these values, it should be possible to calculate the 3rd value.

To perform these calculations, you only need 4 basic pieces of information about the motor:

- Pack V @ No Load RPM
- No Load RPM
- Ohm Winding Resistance
- Desired W Full Throttle

For example:

devin, post:75, topic:17037 Wrote:Desired Full Throttle Electrical W: 2000W
Pack V = 50V fixed constant
Ohm Resistance = 0.0415ohm
No Load RPM = 4500rpm
Batt Max Setting = 40.00A
Motor Max Setting = 219.52A

~0w electrical @ 100% duty = 4500.00 rpm
1000w electrical @ 100% duty = 4425.29 rpm
2000w electrical @ 100% duty = 4350.60 rpm
2000w electrical @ 95% duty = 4083.92 rpm
2000w electrical @ 50% duty = 1690.37 rpm
2000w electrical @ 43.12% duty = 1324.43 rpm
2000w electrical @ 18.22% duty = 0 rpm

In simple terms to predict all motor states you only need to know Pack V @ No Load RPM, No Load RPM, Ohm Winding Resistance & Desired W Full Throttle.

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/278,2017-02-04 16:06:50 UTC
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