Ingineerix Takes Us Inside A Tesla Model 3 Body Controller

AUG 12 2018 BY MARK KANE 17

Tesla Model 3 pushes the automotive industry into the future of how the cars will be made.

Here is a detailed look at the car’s Front Body Controller.

Ingineerix once more provides insights into the Tesla Model 3 architecture, presenting the VCFRONT (Front Body Controller), one of the three body controllers on-board.

It’s powered from the 12 V battery and distributes low-voltage power to other two controllers. The entire unit is highly integrated and fuseless (no fuse box).

Tesla Model 3 – VCFRONT (Front Body Controller) (Source: Ingineerix)

“In this quick video we take a detailed look inside one of the 3 body controllers used in the Model 3. This one is designated VCFRONT by Tesla.

Main components BoM:

Main Microcontroller: ST SPC56EC74L8
Fan & Pump Motor Controllers: LV8907 (3)
20A Schottky Diodes: ON Semi MBR2045EMFS
235A N-Channel MOSFETs: ON Semi NVMFS5C426N
5A Low VF Schottky Diodes: Nexperia PMEG045V050EPD
Dual Smart High Side Switch: Infineon BTS5020-2EKA
Single Smart High Side Switch: Infineon BTS5008-1EKB
16bit low power I/O port: NXP PA9539RPW (2)

Unknown ST part: VN1TT4 (Likely a high-side driver)”

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17 Comments on "Ingineerix Takes Us Inside A Tesla Model 3 Body Controller"

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The main difference between this and another new car is the lack of a fusebox.
I’m not sure if the lack of a fusebox is a major advantage. Makes it harder to add equipment, and do alterations to the vehicle.
New cars tend to have at least a couple of control boxes. Depend on who makes the car, and the parts. Some use a few, and some are just full of small control unit boxes. A box for each unit it controls. Something that reduse harness length, reduce time and cost to replace is good in my book.
What is the price for each of these units Tesla har here?

I agree just because something doesn’t have a fuse doesn’t magically make it better. Everything Tesla does isn’t necessarily better it’s just different. You ask yourself what is cheaper to replace a fuse or a board?

Reduce cable lenght as main Ecu is inside cabin unlike most cars where Ecu is inside trunk. So running a serial line to this VCfront controls fans and pump speeds based on programmed values. Makes it easier to cable and more reliable.

I have never seen an ECU in the trunk. What car is this?

Lol why do people think this functions like a fuse just because it replaces them? The board doesn’t get replaced if a circuit trips, it’s just a software circuit breaker that resets itself. Nice and elegant. As Ingineerix explains in the videos, this is a significant reduction in BCMs and wiring over other modern cars in this class, and a drastic improvement over the S/X.

I think we can expect the S/X to receive a similar reduction in wiring when they are refreshed, hopefully no later than the end of this year.

It’s good to see Tesla keep making advances which keep its EV tech years ahead of any other EV maker.

Go Tesla!

Sounds like something that would happen in a major overhaul, rather than a minor refresh.

If it happens at all. At the much lower production volumes of Model S, it might not actually be worthwhile.

As long as it has all the protection needed, and survive some weird shorts that may happen somehow – it’s all good. Time will tell, how well it works.
In general I feel harnesses in many products like cars, boats, copiers and some industrial products are primitive, and don’t use the advantages fairly new technology can offer. Too little use of common data buses, that is shared between functions/units and so on.
Some of the reasons may be for ease of parts replacement, search for errors or just how much the harness can handle over the life of the product it’s in.

“You ask yourself what is cheaper to replace a fuse or a board?”

Why would I want to spend money on fuses and chasing physical wires in a fuse box in search of an electrical problem, when I can have the car self-diagnose the problem and reset automatically without having to replace any fuses?

Your “either-or fallacy” presumes that these boards will fail every time there is an electrical problem. There is absolutely nothing that even remotely suggests that.

It would be like a 1940’s home owner objecting to those new-fangled household breakers because he would rather keep buying fuses.

I work with electronics daily that has self diagnostic features, and usually it works more or less – but sometimes a short in a stupid component like a solenoid can result in a situation where the diagnostics systems says there is a fault in a totally different part/system, or don’t detect the fault in the system at all. In some situations a new firmware may be the solution, but not always. When it works, it is highly useful and saves a lot of time. Self diagnostic is used in all new cars as well, but is often hid from the customer. It may just offer a lamp that blinks check engine or something like that. Modern cars have the option to give a whole lot of better information to the customer, if the manufacturer want to. I hope Tesla does that with this system, as they have the screen that can easily display the picture of the vehicle, and highlight the part with a potential fault. To know the price of the board would of course be nice. Is it priced like a high end computer main board, or like an advanced controller board for a CNC machine of some… Read more »
Well, I’m by no means an expert: but my best guess is that this board should likely be cheaper than a high-end PC mainboard… The board itself should be much cheaper, since it has considerably lower routing complexity. (Less layers; larger structure sizes; possibly simpler materials.) The main controller is nothing special AIUI — probably much cheaper than the ICH on a computer mainboard. The amount of secondary ICs seems similar to older mainboards. (Newer ones tend to have fewer, more integrated ICs…) Beside a few VRMs and capacitors (much fewer and smaller than on a high-end PC mainboard), there is quite a bunch of power FETs. I have no idea how much these cost — but I’d guess not more than the powerful VRM chips on a PC mainboard? There are more of them here; but no capacitors or inductors to complement them — so total price is probably not higher (or at least not much) than the VRM banks on a high-end mainboard. Aside maybe from the calibrated shunt resistors (how much do these cost?), I don’t see anything else potentially expensive on there. No RF controllers, no high-bandwidth I/O interfaces, no audio circuits… Crucially, the production volume… Read more »

For aftermarket use, you can just add on additional old-school fuse boxes directly off the battery and use a relay to power different fuse boxes off of always on power, ignition power, etc as needed.

This is better than all the old-school hacks to tap into the existing power anyways, which are well known for causing electrical problems in car electrical systems going back decades.

The reality is that modern cars have had modern CAN-Bus systems for more than a decade. The old school 1950’s-1990’s hot-rodder style electrical system hacking has been a bad idea for quite a while. It is much better to isolate your aftermarket electricals as much as possible from modern electrical systems.

Yeah, I agree to everything you say.

To add a fuse box directly off the battery will do the trick now – but when the manufacturers find a way to remove the 12V battery permanently – they must offer a connector people can use to add equipment at least.

To tap into excisting electrical wires may result in error codes in the cars diagnostics system.

The guy also has a pair of videos specifically addressing the topic of safely getting 12 V for external components…

I’m not sure removing the battery will really change all that much. AIUI, it just means that the DC-DC converter will have to be always-on, even when the rest of the HV system is disconnected. How the 12 V system is handled beyond the DC-DC converter, should remain pretty much the same I’d assume?

Fuses or circuit breakers exist to protect the wiring from melting. If this box protects the wiring, then fine. It’s like upgrading from fuses to re-settable circuit breakers. Does anyone know if the TM3 provides a circuit for user-added equipment?

Not sure what your point is exactly — but this is precisely the kind of integration Munro credited with the low manufacturing cost of the Model 3.

(His report would provide you with detailed costs of the modules — but it ain’t cheap 😉 )

Well, its definitely cheaper to make a vehicle without fuses or circuit breakers – but hopefully there is nothing ever going wrong with these ‘electronic fuses’.

I wonder if the fan circuit on the Fisker Karma had electronic fuses? They had the Model 3 commonality in that they had no fuses in the radiator fan circuit, nor circuit breakers either.

Worked great until something went wrong. Then a few joints burned down.

But then, there has never ever been any Tesla Roadster product that has overheated to the point of fire.