[brian_]

A controller that regulates the workings of the inverter/ motor. Like an the ECU for an engine. Just a single controller to drive the car.

These are commonly called a "VCU" (vehicle control unit) in EV conversions, and are offered for the most common drive units & inverters, which are the old Model S/X induction units, the Nissan Leaf, and now the Tesla Model 3.

Another example is the Dilithium VCU from Thunderstruck; that's not an endorsement at all, just the first example that came to mind with a supplier link.

 

[Toretto]

These are commonly called a "VCU" (vehicle control unit) in EV conversions, and are offered for the most common drive units & inverters, which are the old Model S/X induction units, the Nissan Leaf, and now the Tesla Model 3.

Another example is the Dilithium VCU from Thunderstruck; that's not an endorsement at all, just the first example that came to mind with a supplier link.

Thank you brian, I am looking into that, (see post #27 below) but was unsure if this enabled me to ditch all but drivetrain. So yes, this is basically a stand-alone motor management unit. Thank you

I'm searching which one of the 4 options would be best for this build.

• The Resolve vcu seems limited to 30kw pack and all stock hardware, since I want to use only the drivetrain....
• Openinverter is not too far geographically, perhaps an advantage.
• Thunderstruck seems the best/ most complete for now

Now I would like to control the engine beyond 10k rpm. I suppose that the maximum kw's are still regulated by the inverter and not adaptable by either
-Thunderstruck VCU
-Resolve EV
-Johannes hubner. Openinverter
- Paul Holmes

Do any of these implement regenerative braking?
What is our best option for simplicity/ most user friendly

As much as we would love to run Tesla batteries, there is an abundance problem. We want to be able to add the full size pack for long runs, but do not need that type of range daily. So permanently installing 16 Tesla cells will not be possible.

Do we stay away from air cooled cells for the permanent pack? Somebody here said that this is the achilles heel on the leaf packs.

Can we, realistically, use 3 separate packs in 1 car?

 

[Toretto]

You didn't get a business plan. You got a marketing strategy.

You CAN operate the Leaf from a single external "module" - lots of people here are using the Resolve controller to exactly do that.

You would be smart to have temperature, voltage, and other telemetry to be able to do PM during charging, unless you're show vs go.

The beauty of what we recommended is little to no mechanical design, other than perhaps adding a few modules to the top of the pack to overvolt the motor.

The car would be stripped of everything but its essentials, but the battery pack and drivetrain are as God, and Nissan, intended them to be...that is THE most RELIABLE build convergence in what's been on the table so far and reliability wins endurance races/rallies. Budget and time is better spent elsewhere than cribbing some angle iron mounts up whose welds will break and spill battery guts all over the road course.

What I would do from there is add a few modules to the top of the cell stack to overvolt the HV section by 10-20%. Run 20% overcurrent and you're close to 300HP.
.
Your build plan allegedly is open for change in any direction, except, of course, for that being recommended here by everybody 🤓

That widebody design, by the way, is gluing foam blocks to the car and shaping them with a knife and a surform and carbody sanding tools. The concept pic I found is a great guide and fortunately doesn't have compound curves, though I'm sure you can easily find an artist or bodywork person to do any sculpting quite easily using this method. From there, a layer or two of carbon fiber or fiberglass, some filler, paint, and you're good. Lots of people would line up to do that build as volunteers, vs working on their mom's Honda Civic that doesn't feed from a nitrous bottle.

I will continue to make corrections, like to your module misperception...none of the original Leaf control or operator interfaces would likely remain working and would likely have been stripped and a Resolve controller would run the drivetrain show, like it would have in the Civic.

Unlike the Civic, the work is substantially reduced, and reliability is orders of magnitude higher if you leave the drive unit and battery pack in the car. Chargers, charger port, public charging ability all stay with the car and should continue working.

When I went to the bank to assist in buying a house, they didn't explain their vision on buying an appartement, or their opinion on the benefits.
Guess what, they assisted me in buying a house!
Stop forcing your opinion on us. You are wrong. We live half across the world from eachother! You know nothing about marketing here, and I doubt anywhere else.

Repeating yourself doesn't make you more right.

Stick with what you do know, with the questions I AM asking. Because you have all the answers we need. This thread has gone for 63 posts with very little information...

 

[remy_martian]

Lots of info. Tons of it. You're ignoring it

16 Tesla modules in a Civic?

😂😂😂

 

[Toretto]

read my comment on field weakening above

What would be the ideal rev range for the LEAF motor?
If one had a gearbox to remain in this range...

Looking at this diagram I would say between 4k and 8k rpm.
The field weakening starts as soon as 2800rpm?

No idea which EM57 version this represents

 

[remy_martian]

If you're building a race car you want to overvolt the motor and toss that graph in the garbage.

All the motors are the same -- the inverters change.

edit: take a look at @Dala's thread on hopping up the Leaf with an inverter swap. He has it on his Youtube channel as well.

 

[brian_]

What would be the ideal rev range for the LEAF motor?
If one had a gearbox to remain in this range... View attachment 127604

Looking at this diagram I would say between 4k and 8k rpm.

Yes, the ideal speed depends on the power requirement, but that's the range.

The field weakening starts as soon as 2800rpm?

No, the break at 2800 RPM doesn't have anything to do with field weakening - it is where the line of constant torque at low speed resulting from the motor or inverter's current limit intersects with the line of constant power at moderate speeds imposed to protect the battery, so the system goes from current-limited to power-limited.

No idea which EM57 version this represents

The form of the data doesn't change much - if at all - between Leaf versions. What changes are the current and power limits. The top edge of the operating range shown in this graph is 80 kW (about 20 Nm @ 2800 RPM, or 80 Nm @ 9800 RPM, or any other combination on the hyperbolic curve between those points), indicating that this is from a motor and controller from a Leaf with 24 kWh or 30 kWh battery (the first generation of Leaf, model years 2011-2017). A later motor and controller combination will look similar but extending further out to the curve corresponding to 110 kW (with 40 kWh battery) or 160 kW (with 62 kWh battery).

 

[57Chevy]

The transition from constant torque to power is usually defined by field weakening so yes, fw quite likely starts at 2800 or 50kph.

94~95% efficiency isn't brilliant for a modern motor design (unless that is the axle efficiency, then it is quite good) and that may be accounted for by fw operating. I haven't looked into it enough though. Each % efficiency loss from the motor adds ~0.8kW to the motor cooling system load, up to the point where it can't reject it, and then the power curve is thermally limited.

The case to avoid is where you are running on the thermal curve rather than the power curve. When your driver is unable to drive to the conditions because the powertrain is choosing how fast to go, it stops being a race and that is the main point I'm getting at here. Videos of Teslas running fast and stuck at 135mph will be sitting on the thermal limiter, even though the driver requests to go faster

This is the same graph somebody posted of a Tesla LDU with an openinverter board on a dyno. Constant(ish) torque changes to fw at 8000rpm or about 62mph

 

[remy_martian]

Tuned to the decimal point for 0-100kph time marketing brags and the economettric drive cycle...

 

[Toretto]

Ok thanks all.
This may be a very silly question, but if so I suppose Remy will bash me accordingly 😁 (I'm learning here!)

Assumption: Tesla batteries are most energydense. So kWh/kg is Lower than alternatives. They charge faster & more efficient than alternatives. (I believe this was stated on a YouTube channel). They are also OEM and cooled

Is there a point where it is smarter to use a lower voltage motor (such as hyper9) with a faster charging Tesla pack?

Or is the higher voltage motor with less efficient heavier (and less kWh) pack better for a long range ev conversion?

So
- less kWh on board, high voltage motor
vs
- more kwh on board, lower voltage motor

 

[remy_martian]

Putting a bunch of small circles is less dense than putting a bunch of small rectangles in a big rectangle.

Laptop batteries made sense because they were CHEAPER at the time.

Bigger circles in that big rectangle are even less dense by 0.86r^2...where Tesla is heading.

There's a point where you decide how much energy you need to store and then you figure out how to make that much energy FIT into the target vehicle. Before you select the battery. Or....you can pick 16 Tesla modules, fit 10 in your Civic, and be the only car in the rally towing a trailer 😂

Starting with "Tesla module" or "Tesla motor" will spend a lot of money in a hurry, create a lot of work and will paint you into a corner regarding making it work in your target vehicle.

See? I didn't say "Leaf" once 😂

The Norwegian must be mellowing me with real problems, like having asbestos to deal with in a build 😬 vs dealing with a more-stubborn-than-me guy continuing to fail at using an overclocked LEAF.

 

[Electric Land Cruiser]

Looks guys, he's asking for our help on how to build an ALL OUT RANGE and EFFICIENCY build. He NEEDS OUR help.

Well, he already decided on the car and the aero and the batteries so besides that he's all ears!

I recommended a LEAF because you wanted to explore battery swapping and you can swap the battery in a LEAF in a matter of minutes.

 

[Toretto]

Looks guys, he's asking for our help on how to build an ALL OUT RANGE and EFFICIENCY build. He NEEDS OUR help.

Well, he already decided on the car and the aero and the batteries so besides that he's all ears!

I recommended a LEAF because you wanted to explore battery swapping and you can swap the battery in a LEAF in a matter of minutes.

Are you being helpful or sarcastic?
I haven't come across another thread on this forum where the car choice is questioned.
This forum is about electric drivetrains, not aero or car choice, so I never meant to discuss that here.

I contacted a company that deals with leaf batteries daily, because I love the idea of a swappable leaf (partial) pack in the trunk. A bit like a fuel cell range extender.

However, others have advised me to build the permanent pack out of cooled cells.

So I thank all of you very much for each and any advice concerning the build.

I have much to learn regarding building an EV, and look up to all you experienced builders with the utmost respect.
So when a new suggestion pops up, I try to pursue that info and hope to end up with a viable building plan. Hence my daily new questions.

For now I am learning, contacting the right people, simulating costs, and trying to come up with the best possible build

I feel like me asking new info is misinterpreted as me being stubborn on this forum. Which is not at all the case, I assure you (Shut up about the car Remy, I'm talking about technical info😛)

 

[Electric Land Cruiser]

Are you being helpful or sarcastic?
I haven't come across another thread on this forum where the car choice is questioned.

I contacted a company that deals with leaf batteries daily, because I love the idea of a swappable leaf (partial) pack in the trunk. A bit like a fuel cell range extender.

So I thank all of you very much for each and any advice concerning the build.

However, others have advised me to build the permanent pack out of cooled cells.

I have much to learn regarding building an EV, and look up to all you experienced builders with the utmost respect.
So when a new suggestion pops up, I try to pursue that info and hope to end up with a viable building plan.

For now I am learning, contacting the right people, simulating costs, and trying to come up with the best possible build

Why do you want to cool the pack? More lines to disconnect when swapping out the battery in your "all our range and efficiency" race or whatever. The LEAF battery only gets a few degrees above ambient in my experience owning one for years and driving it at 94 MPH a lot.

Good luck sounds like you already know everything needed you just have to build it now!

 

[Toretto]

Good luck sounds like you already know everything needed you just have to build it now!

No I don't! I value your opninion as well as the person's who suggested that my application required cooled batteries. Since I don't know half of it I need more info. Which you've only now just given me.
Actual info from your own application in practice.

So thank you for that. Please understand that I am between a rock and a hard place with all these opinions. I need to sift through all of that info and ask the right questions. I'm sorry you feel offended when I do...

But what I'm talking about is a cooled permanent pack, and a swappable trunk pack. It seems logical that the swappable pack be not cooled. (In my OP I had no idea some EV's had aircooled batteries)

Somebody gave me the advice to use a cooled pack in my application. If you feel that this is not necessary, I invite you to share your opinion.
This way you both help me out, and I learn more.

This whole thread is meant to get to know '"all" possibilities.

 

[Electric Land Cruiser]

No I don't! I value your opninion as well as the person's who suggested that my application required cooled batteries. Since I don't know half of it I need more info. Which you've only now just given me.
Actual info from your own application in practice.

So thank you for that. Please understand that I am between a rock and a hard place with all these opinions. I need to sift through all of that info and ask the right questions. I'm sorry you feel offended when I do...

But what I'm talking about is a cooled permanent pack, and a swappable trunk pack. It seems logical that the swappable pack be not cooled. (In my OP I had no idea some EV's had aircooled batteries)

Somebody gave me the advice to use a cooled pack in my application. If you feel that this is not necessary, I invite you to share your opinion.
This way you both help me out, and I learn more.

This whole thread is meant to get to know '"all" possibilities.

Swapping half of a battery just doubled your problems. Let's say you drive your car and run the battery down. You pull over to swap the fully charged pack in the trunk. Now, how do you keep that fully charged pack from discharging into the empty pack in the car instead of driving down the road? And now the permanent pack in the car is just a lump of dead weight providing nothing to move the car?

Your conundrum over which motor is more efficient, Nissan or Tesla? Which battery cells have the highest energy density? Etc etc are really trivial questions. Your range is going to be far more affected by 5-10 MPH variation on your top speed than any of those other variables.

You want to know "all" possibilities except the possibility of using a different, more suited vehicle, for instance. And if you start building a vehicle before looking at a rule book for the competition you are entering, you're going to have a bad time.

 

[Toretto]

Well, my idea was to swap the trunk pack at charging Points. I read somewhere (this is successfully attempted before) that a different pack runs a different BMS and needs to be physically connected and disconnected from the inverter. At that Point you disconnect the other pack. If this is completely wrong, I would love to learn.
But any battery that Runs on empty is Dead weight.
I was thinking we could add several kWh without extra charging time at a stop. We would need several packs...

The point of this build would be to have an efficient car. The driving style applies to each and every energy powered vehicle.

There seems to be some confusion still.
These are road rallies. No competition. No rulebook.
Just organized open road runs for car enthousiasts.
Think Gumball, or Lux rally, without the extravaganza...

And I firmly believe that a car enthousiast can choose his own car.

You have given me great info, I did also read your complete build thread. Love it!

 

[Electric Land Cruiser]

It's hard to give advice without knowing the distance you intend to go and the average speed. EV conversions are hard enough as it is, let alone all the swapping etc. There are many way to swap out part of the pack, technically it's not a big deal. If you can convert a car to EV then that is a piece of cake. Like I said you are diving into such minute details and requirements without even stating how far or how fast you want to go.

Like I said in my first post based solely on the title of this thread I'd pick a 90s convertible like a Sebring or Toyota Solara, hack the windshield off and build a tonneau, and do a LEAF motor in front and pack as many batteries as possible everywhere else.

 

[Toretto]

Well my reasoning was that the distance doesn't really matter. After the First charging it's just repeat everything all over again, right? If it was a matter of getting there on 1 charge that would be different... range between charges hopefully the likes of 400 miles. But that's just hopes and dreams I suppose...

The speed will always be a tradeoff with range. So my answer is: as fast as possible. The juice usage will have to be monitored on that exact moment in those exact conditions.

Thus, we want to build it as efficient as possible. Because in my mind, that means more efficient under any circumstance... It will be percentage wise. Whether we drive it like a granny or a looney.

We want to cross countries, so 1000mile commutes are on the table. Does this help?
I thought this was mentioned somewhere, but I don't expect everybody to read everything I post. Feel free to ask...

 

[remy_martian]

Again you're not making any sense. You want speed, you want efficiency, it's not a race but enthusiasts, yet you're using Mario Andretti's crew for a battery change pit stop.

Step back, frame exactly what the rules and conditions are for this competition, what road speed limits are since it is not a closed course (giving you 150MPH capability is pointless), what terrain is involved, what types of curves, etc. A rulebook of what you can and can't do. Road conditions, climate, etc.

Frankly, you've come across scatterbrained in the requirements, putting everyone here at odds with you for embracing idiocy, bias, and lore, over coming up with the optimal solution set (which is a widebodied Leaf, of course 😂)