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Need for speed, 6wd?


#41

Quad 80100 :yum:


#42

Yea exactly that will surly do the trick


#43

Quad car alternators anyone?


#44

Just use a JATO


#45

Guys first try dual 80100 then talk about quad 80100 :laughing: it’s like day and night difference compared to 6384 :smiley:

I guarantee you will shit pants first time you press throttle coming from 6374 2wd/4wd :smiley:


#46

Question, is it night and day even with the same vesc settings?


#47

Well you get more with more settings, but even with the same settings, its just different consumption of current :slight_smile: For e.g. just to move board from standstill it requires more power than with smaller motors :slight_smile: not like by small margin but by a lot :slight_smile: Also with same settings I lost half of range so it means motors consume more power (internal resistance is much lower which means in any way it consumes more current)

EDIT: yes it feels kinda day and night you press a bit of throttle and it just pushes you back on the board. Some people were even scared to ride it :smiley:


#48

I’m confused. Ur saying with ur 80xx size motors they’re taking more power for the same acceleration off the line as the 60xx and also less efficient on the straight? I’d have thought the bigger motor would be slightly faster off the line w the same settings and also more efficient on a flat continuous.


#49

same kv same settings should be same acceleration regardless of stator size…


#50

I don’t know who spread the idea that bigger motor the more efficient it is… Because on the same idea it would mean you can pick up 200200 motor and ride without much current :smiley:

Torque in motor is proportional to the air gap flux, number of conductors in the slots and current in those conductors. Assuming the air gap flux density stays the same, then a longer stator will mean more air gap flux and your torque will increase. At the same time, a longer stator will slightly increase the total length of your wire, so your resistance will increase and that will cause the torque to drop slightly, but because your motor is longer, it also has the ability to dissipate more heat which increases your rated torque. So the overall effect is a longer motor will increase torque, assuming every other parameter of the motor stays the same.

So talking same current and throttle position bigger motor will product more torque.

But because 80100 are much bigger and has more and bigger bearings, bigger magnets and etc it has much more resistance to spin so current consumption is higher to start it moving so efficiency drops, but because you have more torque it kinda counters it and in the end you have more torque but higher current consumption and oh boy its 3 AM and my head doesn’t work anymore… :smiley:

I don’t know if my paragraphs even makes sense… :smiley:


#51

But the torque is different man… :smiley:


#52

torque per motor amp w/ bldc is the inverse of the kv when stated in terms of radians per second per volt.

KT = 60 / (2 * pi * KV)


#53

So you mean flux doesn’t matter for motor? :smiley:


#54

the KV measurement includes the flux…

the larger stator can handle more amps before it becomes non-linear (saturates)


#55

So you saying that 1m stator vs 1cm stator will product the same torque? :smiley:


#56

before saturation current is reached on the 1cm (if same kv), yes


#57

Bigger bearings can take more amps but u could work it so it wasn’t much difference.

Magnetic cogging of a bigger motor is there but disappears under power or at least is no longer a resistance

The copper losses would go down for sure with the bigger motor and often the source of most loss but maybe the big motor has more iron losses.


#58

Aren’t in all this talk we ignoring battery? That’s the biggest limitation unless you go high discharge Lipo


#59

So you know, that windings resistance and heat and etc will affect the torque?


#60

the resistance affects the losses per motor amp not the torque.

(lower resistance draws less electrical watts for the same motor current and torque at the same kv & rpm)