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Hi Paul
I’m trying to understand what is going on
On the ¼ mile I could look at my instruments
After a brief surge of acceleration I was pulling a continuous 200 amps (battery)
That is about right for a constant speed of 59mph (not very aerodynamic)
I had the pedal down still
My “theory” is that the controller was at max – 100%
But there was so much Back EMF that there was not enough voltage left over to drive more current through the motor
I had about (don’t remember the actual reading) 120v
So I think BEMF = 100v
Assuming that the motor was “saturated” and BEMF was proportional to current and speed that gives me a point on the line
3500rpm – 200Amps = 100v
Making up a quick spreadsheet I come up with
1000 amps to about 700rpm - 19Kph
800 amps to about 900rpm - 25Kph
600 amps to about 1100rpm - 30Kph
500 amps to about 1500rpm - 40Kph
400 amps to about 1900rpm - 50Kph
200 amps to about 3500rpm - 95Kph
And that is about how it felt - really fast off the line - then disappointing
So is that "reasonable" - or what am I missing
Specifically – am I correct about the controller?
Is that a reasonable amount of BEMF?
From that my 11 inch Hitachi motor is producing about three times as much BEMF at a given rpm/amps as the tables for a Warp9
I expected more – but not that much more
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