openinverter forum

Hello folks!

starting to plan my EV project and looking trough the internet.

my vehicle will consist of some batteries,VCU, wheels and a probably a Tesla small drive unit. the finnished product will end upp somwhere around 500kg total weight. the project is kind of a small secret for now, so bare with me

My first question for this exelent community is about the output power of the SDU.

Google gives me these numbers:
Max Current 650 Amps DC
Max Power 220 kW (300 Hp)
Max Torque 330 Nm (243 lb-ft)
Output Power (12 min.) 90 kW (121 Hp)
Continuous Power 35 kW (47 Hp)
Max Regenerative Braking 90 kW (280 Amps)

so this means that if i go flat out for more than a few seconds the motor will only deliver 90kw and after 12 minutes i can walk faster?

and sorry for my bad english

Ohh, and is there any diffrence in front and rear SDU? google does not give me a 100% relaiable answer

JockE28 wrote: ↑Mon Oct 11, 2021 12:04 pm Hello folks!

starting to plan my EV project and looking trough the internet.

my vehicle will consist of some batteries,VCU, wheels and a probably a Tesla small drive unit. the finnished product will end upp somwhere around 500kg total weight. the project is kind of a small secret for now, so bare with me

Continuous Power 35 kW (47 Hp)
so this means that if i go flat out for more than a few seconds the motor will only deliver 90kw and after 12 minutes i can walk faster?

Well yes....and no. I have 28kWh motor in my Mazda and i demonstrated 180km/h performance (only once!) over some 15km stretch of highway.
At that speed motor developed 80kW and it quickly overheated to 180degC. Mazda is 1200Kg or thereabout.
Other than that the car was quite fun to drive because for every day driving 28kW was adequate and i would rarely command more than 50kW from motor. The biggest obstacle would be a series of highway hills on my way to the sea side. There i would have to drive at 90km/h if i wanted lower than 150degC. And the temperature would not go down easily.

500kg car will fly! Depends on the application.
If you have liquid cooling you are able to command high power and dissipate it during nominal speed cycles.

JockE28 wrote: ↑Mon Oct 11, 2021 12:04 pm so this means that if i go flat out for more than a few seconds the motor will only deliver 90kw and after 12 minutes i can walk faster?

It means it can output 90 kW for 12 minutes and then needs to slow down because it's overheated

johu wrote: ↑Mon Oct 11, 2021 12:29 pm

JockE28 wrote: ↑Mon Oct 11, 2021 12:04 pm so this means that if i go flat out for more than a few seconds the motor will only deliver 90kw and after 12 minutes i can walk faster?

It means it can output 90 kW for 12 minutes and then needs to slow down because it's overheated

But if motor temperature is obtained below "overheating", it would be possible to runt it att 200kw forever?

Most of all the coating of the coils must hold up. If you manage to feed the inlet with ice cold water, then maybe, yes.
Question is, how is a 500 kg vehicle supposed to use 200 or even 90 kW for a prolonged period? All hills a finite. Just build it

johu wrote: ↑Mon Oct 11, 2021 12:49 pm Most of all the coating of the coils must hold up. If you manage to feed the inlet with ice cold water, then maybe, yes.
Question is, how is a 500 kg vehicle supposed to use 200 or even 90 kW for a prolonged period? All hills a finite. Just build it

Haha, not sure. but im an "all about the power" guy, and i dont like to runt out of it

i will refrase:

if i hit the throttle and use all of the watts for 10 seconds then release the throttle, will it take a second for it to recover or minutes?


Im Very much new to EVs

JockE28 wrote: ↑Mon Oct 11, 2021 12:56 pm i will refrase:
if i hit the throttle and use all of the watts for 10 seconds then release the throttle, will it take a second for it to recover or minutes?

Well you can calculate, but reality will tell you it will take at least 1xtimes for power cycle to reduce dT. And dont forget regen (genarator) also heats up the motor.

I recommend you read this thread. He has dealt with the permanent performance. After the first approach with a Tesla LDU, he switched to Model 3.


viewtopic.php?f=11&t=1511

muehlpower wrote: ↑Mon Oct 11, 2021 1:03 pm I recommend you read this thread. He has dealt with the permanent performance. After the first approach with a Tesla LDU, he switched to Model 3.


viewtopic.php?f=11&t=1511

interesting, as google claims the M3 RDU can provide less Peak power then the old SDU from model S

arber333 wrote: ↑Mon Oct 11, 2021 1:02 pm

JockE28 wrote: ↑Mon Oct 11, 2021 12:56 pm i will refrase:
if i hit the throttle and use all of the watts for 10 seconds then release the throttle, will it take a second for it to recover or minutes?

Well you can calculate, but reality will tell you it will take at least 1xtimes for power cycle to reduce dT. And dont forget regen (genarator) also heats up the motor.

im with you.

Regen is less important then power in this case

JockE28 wrote: ↑Mon Oct 11, 2021 1:20 pm interesting, as google claims the M3 RDU can provide less Peak power then the old SDU from model S

Yup. But for that race application, where continuous power is more important, the M3 motor was more suitable.
The S motor is induction while the M3 is permanent magnet, so the rotor in the S motor heats up. This was the limiting factor for the continuous power of that motor.

As stated by the builder:
"You can never have too much power! From our limited data, we saw that we were able to put down an average of about 95kW with the M3 drive unit. Peak power was in the 220kW range. Peak for the Model S drive unit was much higher, but we were under 70kW average at the end of a race."

More HP for longer = faster.

Isaac96 wrote: ↑Mon Oct 11, 2021 3:56 pm

JockE28 wrote: ↑Mon Oct 11, 2021 1:20 pm interesting, as google claims the M3 RDU can provide less Peak power then the old SDU from model S

"Peak power was in the 220kW range. Peak for the Model S drive unit was much higher, but we were under 70kW average at the end of a race."

More HP for longer = faster.

Yea. But that's referring to the large unit. I'm comparing with the small drive unit as it has the same claimed peak power as the M3 stated in this post.

If M3 motor can provide same peak as the model S SDU
The choice is easy - M3

As it has the same peak power as SDU and faster recovery (~95kw average in racing application)

DOE dyno tests state 211kw for the 2019 M3 LR RWD, versus the 220kw the SDU is usually rated for.

But here's a dyno test for a LR RWD M3.
https://insideevs.com/news/339085/a-hid ... ong-range/

It claims a peak of 325hp. Versus the 294hp of the SDU.

So in terms of both peak and continuous the M3 looks much better.

As a reminder, unless you are road racing, you aren't using the full rated power most of the time. In normal driving circumstances, whether EV or ICE, cruise doesn't require nearly the power acceleration does.

Remember an ICE's rated power is at WOT, at a (typically) high RPM. At cruise its usually turning half or a third of that speed and using barely any throttle.

Trust me, I'm a "more power is always good" guy, but I wouldn't get too worked up about how quickly a motor will derate for a street car, especially if it's an OEM motor/inverter.

How much batteries do you expect to put in a 500kg vehicle? 90kW for 12 minutes obviously requires at least 18kWh which generally weighs at least 150kg if it needs to also support 200kW peak output.

Seems like 1120980-00-F 3D1 is the partnumber for the 325hp one.

There is one available locally

celeron55 wrote: ↑Tue Oct 12, 2021 2:43 am How much batteries do you expect to put in a 500kg vehicle? 90kW for 12 minutes obviously requires at least 18kWh which generally weighs at least 150kg if it needs to also support 200kW peak output.

That's about right.

JockE28 wrote: ↑Tue Oct 12, 2021 6:12 am Seems like 1120980-00-F 3D1 is the partnumber for the 325hp one.

There is one available locally

265kw according to Ingenext! (355hp input, so about 91% efficiency?)
https://ingenext.ca/products/tesla-mode ... 20980-00-f