Crazy LDU and SDU ideas, help needed

Topics concerning the Tesla front and rear drive unit drop-in board
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santoscollection
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Crazy LDU and SDU ideas, help needed

Post by santoscollection »

Hi everyone. Long time browser and finally decided to start my project. However I need some assistance before I order a logic board. I need to know if my plan will even work.

I have a BASE LDU and would like to install it in the rear of a Civic, however because of mounting issues I need to place it in front of the drive hubs. So I will need to spin the motor in reverse. (I assume I need the zeroev oil pump) my question is if I also install the front drive unit from a 75D in the front but in normal direction can I just hook up the front unit via can to the rear drive unit? Will it still drive the front one with rear spinning backwards? If not is there a way to control both with one pedal even if there is not torque vectoring. I’m probably getting ahead of myself here. But any help in this would be greatly appreciated!
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Re: Crazy LDU and SDU ideas, help needed

Post by johu »

Yes you can couple them via CAN and have them spin in the correct direction :)
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Re: Crazy LDU and SDU ideas, help needed

Post by FJ3422 »

Like your idea !
I had the same thoughts. Technically no problem, until I realised what batterypack would be needed to supply the required current during acceleration..
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Re: Crazy LDU and SDU ideas, help needed

Post by P.S.Mangelsdorf »

santoscollection wrote: Thu Dec 17, 2020 5:56 am Will it still drive the front one with rear spinning backwards?
Yes. Most likely the easiest way is to run the throttle pedal via CAN and the direction control via 12v. Just change which pin the switched12v is going to.

i.e. to go forward, send 12v to the front motor's "forward" pin and 12v to the rear motor's "reverse" pin. To go backwards, do the opposite. See the wiring diagrams on Damien's GitHub.
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Re: Crazy LDU and SDU ideas, help needed

Post by johu »

P.S.Mangelsdorf wrote: Thu Dec 17, 2020 4:15 pm Yes. Most likely the easiest way is to run the throttle pedal via CAN and the direction control via 12v. Just change which pin the switched12v is going to.

i.e. to go forward, send 12v to the front motor's "forward" pin and 12v to the rear motor's "reverse" pin. To go backwards, do the opposite. See the wiring diagrams on Damien's GitHub.
That said you could even do that connection via CAN
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Re: Crazy LDU and SDU ideas, help needed

Post by EV_Builder »

P.S.Mangelsdorf wrote: Thu Dec 17, 2020 4:15 pm
santoscollection wrote: Thu Dec 17, 2020 5:56 am Will it still drive the front one with rear spinning backwards?
Yes. Most likely the easiest way is to run the throttle pedal via CAN and the direction control via 12v. Just change which pin the switched12v is going to.

i.e. to go forward, send 12v to the front motor's "forward" pin and 12v to the rear motor's "reverse" pin. To go backwards, do the opposite. See the wiring diagrams on Damien's GitHub.
I have stated before, you never should do that. Forward motion means that the motor is spinning in the direction what would result in forward vehicle motion.

If you want the motor to spin in the opposite direction you should invert the direction of the motor. Not use the reverse input for forward vehicle movement. Why? Well one day the software is becoming smart and then you are confronted with these choices.
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Re: Crazy LDU and SDU ideas, help needed

Post by Lowcoe »

gonna be one fast civic
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Re: Crazy LDU and SDU ideas, help needed

Post by santoscollection »

Progress update. Decided on two LDU one in front and one in the rear. Yes for now I’ll have them both turned down as pack power will be an issue

Can the new board control both motors as in rear master and front slave even though they are both LDU?
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Re: Crazy LDU and SDU ideas, help needed

Post by P.S.Mangelsdorf »

santoscollection wrote: Mon Jan 31, 2022 1:14 pm Can the new board control both motors as in rear master and front slave even though they are both LDU?
My understanding is that you'd need one board in each, and then run the throttle to one, and use CAN for it to tell the other what the throttle position is.
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santoscollection
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Re: Crazy LDU and SDU ideas, help needed

Post by santoscollection »

P.S.Mangelsdorf wrote: Mon Jan 31, 2022 1:36 pm
santoscollection wrote: Mon Jan 31, 2022 1:14 pm Can the new board control both motors as in rear master and front slave even though they are both LDU?
My understanding is that you'd need one board in each, and then run the throttle to one, and use CAN for it to tell the other what the throttle position is.
That’s exactly what I needed to know. Anyway to confirm this and that can from one motor will drive the other? I know it will if one LDU and one sdu but will it work with two LDU?
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Re: Crazy LDU and SDU ideas, help needed

Post by Isaac96 »

Yes it will work with dual LDU. That's a hell of a lot of power!
The OpenInverter boards are pretty fully configurable. If you have an OpenInverter board in each LDU then they will work together.
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Re: Crazy LDU and SDU ideas, help needed

Post by santoscollection »

Isaac96 wrote: Mon Jan 31, 2022 6:42 pm Yes it will work with dual LDU. That's a hell of a lot of power!
The OpenInverter boards are pretty fully configurable. If you have an OpenInverter board in each LDU then they will work together.
It should be fun. This is my first ev conversion so I’m learning as I go. Not sure if ill be controlling them with just analog inputs or a vcu. I do have a gen2 Tesla charger and a volt dcdc I need to get going also. What are you thoughts on the combo?
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Re: Crazy LDU and SDU ideas, help needed

Post by EV_Builder »

Not sure if you forgot/forget but the motors have an internal oil pump which is directional...

Hope you didn't. How did you solve?
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Re: Crazy LDU and SDU ideas, help needed

Post by catphish »

EV_Builder wrote: Mon Feb 07, 2022 6:36 am Not sure if you forgot/forget but the motors have an internal oil pump which is directional...

Hope you didn't. How did you solve?
There's an of the shelf reverser for the LDU. I'm about to start work on reversing the SDU pump, assuming such a thing turns out to be possible
santoscollection
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Re: Crazy LDU and SDU ideas, help needed

Post by santoscollection »

EV_Builder wrote: Mon Feb 07, 2022 6:36 am Not sure if you forgot/forget but the motors have an internal oil pump which is directional...

Hope you didn't. How did you solve?
I already have two reverse rotation pumps in the drive units
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