Tesla Motors electric motor vs. YASA electric motor and what is important for EV

[nech12]

Hi Guys,
After review of several videos and electronic vehicles, I have some questions and may be you can help me with them.
For a long time I was thinking that Tesla produce the best electric motors for e-vehicles (AC Induction). Recently I found YASA motors (http://www.yasamotors.com/) with incredible axial-flux motors. Below is a table that I created to compare Tesla motor vs. YASA motor:

Company / Motor	Motor Weight (kg)	Peak Power (kW)	Continuous Power (kW)	Peak Torque (Nm)	Continuous Torque (Nm)	Voltage (V)	Max. speed (rpm)	Nominal speed (rpm)	Efficiency (%)	Peak power density (kW/kg)
Tesla
2015 Tesla Model SP	68	375	n/a	600	n/a	320	15 300	0-5100		5.5
2015 Tesla Model S85	68	285	n/a	440	n/a	320	14 800	0-5800		4.2
2012 Tesla Model S60	50	225	n/a	430	n/a	320	14 200	0-5000		4.5
2007 Tesla Roadster	32	225	n/a	370	n/a	240	14 000	0-5400		7.0
2007 Tesla Roadster Sport	32	223	n/a	400	n/a	240	14 000	0-5100		7.0
YASA Motors
Custom Motor	n/a	800	400	4 000	1 000
YASA-750	33	100/200	90	790	400	350/700	3 250	0-2500	>95%	6.0
YASA-P400 Series	24	160	100	390	300	700	7 500	0-4800	96%	7.4
YASA-400	24	90/165	50/70	360	250	350/700	7 500	0-4500	>95%	7.5

These numbers have raised important questions to me:

1. Is peak power density is the most important factor for EV electric motor?
2. I think that we should look at Peak Torque and Peak Power combination of factors. I mean the best electric motor is a motor with low Peak Power, which means low energy consumption, and high Peak Torque, which means strong driving characteristics.
3. As I understand, Voltage is also important because if we apply high voltage we will get higher Peak Power and as a result higher Peak Torque. The main problem is that high voltage controllers/invertors cost much more then low voltage (for example 350 VCD vs. 700 VCD).

So I will be glad if someone can validate my findings and comment factor is the most important to consider on electric motors for EV.

Thank you

 

[IONHORSE]

HI Nech 12,
I know its a long time since you first posted but here's an answer....

The yasa motors are quite incredible but require high voltage to maintain their power over longer ranges. What a higher voltage means is far less current is needed to get the same power. This means that the batteries can run safer and dont require as much cooling (P=V^2/r rather than (P=I^2*R). The tesla motors can be assumed to need between 900-1200A to generate the quoted peak power. The yasa motors run at around 250A max which in my opinion at least is a bit safer. Our motorbike the ION HORSE is running a yasa p400 with the above specifications. The question of which is more important depends on what you need it to do. A peak torque is great but the motors get very hot very quickly if you don't have sufficient cooling to run them at full power all the time. A continuous power figure is what the motor can supply for a period of time and is produced by what the manufacturer tests the motors to be safe for. If you can increase the cooling ability then in theory you can increase the continuous power figure. The density, i think, is irrelevant if you dont know the size and weight of the controller and batteries. As they will certainly weigh more. Our battery pack is around 85-90KG! and the controller is another 15+ so in total the energy density is far than a racing internal combustion motorbike engine. Although a fair bit more useable and torquey.

I hope this helps.