Exploring Tesla Model S High Voltage Cabling

January 13, 2022 by Chris Lott 36 Comments

When he’s not busy with his day job as professor of computer and automotive engineering at Weber State University, [John Kelly] is a prolific producer of educational videos. We found his video tracing out the 22+ meters of high voltage cabling in a Tesla Model S (below the break) quite interesting. [John] does warn that his videos are highly detailed and may not be for everyone:

This is not the Disney Channel. If you are looking to be entertained, this is not the channel for you.

We ignored the warning and jumped right in. The “high” voltages in the case of an electric vehicle (EV) like the Model S is approximately 400 volts. Briefly, external input via the charge connector can be single or three phase, 120 or 250 VAC, depending on your region and charging station. This get boosted to a nominal 400 VDC bus that is distributed around the various vehicle systems, including the motors and the battery pack.

Rear Modules

- Charge receptacle
- On-board charger module
- Rapid splitter
- Rear motor inverter

Front Modules

- High voltage junction block
- Cabin air heater
- DC to DC converter
- Battery coolant heater
- Air conditioning compressor
- Front motor inverter

He goes through each module, showing in detail the power routing and functionality, eventually assembling the whole system spanning two work benches. We liked his dive into the computer-controlled fuse that recently replaced the standard style one, and were impressed with his thorough use of labels.

If you’ve ever been curious about the high voltage distribution of a EV, grab some popcorn and check out this video. Glancing through his dozens of playlists, [John]’s channel would be a good place to visit if you’re interested any topic related to hybrids and electric vehicles, drive trains, and/or transmissions. We’ve written about some Tesla teardowns before, the Model 3 and the Model S battery packs. Have you worked on / hacked the high voltage system in your EV? Let us know in the comments below.

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An image describing parts of a Tesla modem board

LTE Modem Transplant For A Tesla Imported Into Europe

January 3, 2022 by Arya Voronova 24 Comments

When modern connected cars cross continents, novel compatibility problems crop up. [Oleg Kutkov], being an experienced engineer, didn’t fret when an USA-tailored LTE modem worked poorly on his Tesla fresh off its USA-Europe import journey, and walks us through his journey of replacing the modem with another Tesla modem module that’s compatible with European LTE bands.

[Oleg]’s post goes through different parts on the board and shows you how they’re needed in the bigger picture of the Tesla’s Media Computer Unit (MCU), even removing the LTE modem’s shield to describe the ICs underneath it, iFixit teardown diagram style! A notable highlight would be an SIM-on-chip, essentially, a SIM card in an oh-so-popular DFN package, and thankfully, replacing it with a socket for a regular SIM card on some extender wires has proven fruitful. The resulting Tesla can now enjoy Internet connectivity at speeds beyond those provided by EDGE. The write-up should be a great guide for others Tesla owners facing the same problem, but it also helps us make electric cars be less alike black boxes in our collective awareness.

Not all consequences of Tesla design decisions are this minor; for instance, this year, we’ve described a popular eMMC failure mode of Tesla cars and how Tesla failed to address it. Thankfully, Tesla cars are becoming more of a hacker community target, whether it’s building a computer-vision-assisted robot to plug in a charging cable, getting it repaired for a fraction of the dealership cost, or even assembling your own Tesla from salvage parts!

Model S Motor And Volt Battery Go Together Like Peanut Butter And Jelly

January 13, 2020 by Roger Cheng 55 Comments

A common project category on this site is “put a Raspberry Pi in it”. For people who wrench on their cars, a similarly popular project is the “LS Swap”. Over the past few years, the world of electronics and automotive hacking started to converge in the form of electric car conversions, and [Jalopnik] proclaims the electric counterpart to “LS Swap” is to put a Telsa Model S motor and a Chevy Volt battery into a project car.

The General Motors LS engine lineup is popular with petro heads for basically the same reasons Raspberry Pi are popular with the digital minded. They are both compact, very powerful for the money, have a large body of existing projects to learn from, and an equally large ecosystem of accessories to help turn ideas into reality. So if someone desired more power than is practical from a car’s original engine, the obvious next step is to swap it out for an LS.

Things may not be quite as obvious in the electric world, but that’s changing. Tesla Model S and Chevrolet Volt have been produced in volume long enough for components to show up at salvage yards. And while not up to the levels of LS swaps or Pi mods, there’s a decent sized body of knowledge for powerful garage-built electric cars thanks to pioneers like [Jim Belosic] and a budding industry catering to those who want to build their own. While the decision to use Tesla’s powerful motor is fairly obvious, the choice of Volt battery may be surprising. It’s a matter of using the right tool for the job: most of these projects are not concerned about long range offered by Tesla’s battery. A Volt battery pack costs less while still delivering enough peak power, and as it was originally developed to fit into an existing chassis, its smaller size also benefits garage tinkerers fitting it into project cars.

While Pi SBCs and LS engines are likely to dominate their respective fields for the foreseeable future, the quickly growing and evolving world of electric vehicles means this winning combo of today are likely to be replaced by some other combination in the future. But even though the parts may change, the spirit of hacking will not.

[Photo: by Jim Belosic of motor used in his Teslonda project]

Researcher uses antenna to clone Tesla key fob

Tesla Opens With Precomputed Key Fob Attack

September 13, 2018 by Jonathan Bennett 43 Comments

This clever precomputation attack was developed by a group of researchers at KU Leuven in Belgium. Unlike previous key fob attacks that we’ve covered in the past which have been essentially relay attacks, this hack precomputes a ton of data, looks for a collision in the dataset, and opens the door. Here’s how it works.

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Salvaging Your Way To A Working Tesla Model S For $6500

September 20, 2017 by Adil Malik 80 Comments

If you possess modest technical abilities and the patience of a few dozen monks, with some skillful haggling you can land yourself some terrific bargains by salvaging and repairing. This is already a well-known ideology when it comes to sourcing things like electronic test gear, where for example a non working unit might be purchased from eBay and fixed for the price of a few passive components.

[Rich] from Car Guru has taken this to a whole new level by successfully salvaging a roadworthy Tesla Model S for $6500!

Sourcing and rebuilding a car is always a daunting project, in this case made even more challenging because the vehicle in subject is fairly recent, state of the art electric vehicle. The journey began by purchasing a black Tesla Model S, that [Rich] affectionately refers to as Delorean. This car had severe water damage rendering most of its electronics and mechanical fasteners unreliable, so [Rich’s] plan was to strip this car of all such parts, and sell what he could to recover the cost of his initial purchase. After selling the working modules of the otherwise drenched battery, motor and a few other bells and whistles his initial monetary investment was reduced to the mere investment of time.

With an essentially free but empty Tesla shell in his possession, [Rich] turned his attention to finding a suitable replacement for the insides. [Rich] mentions that Tesla refused to sell spare parts for such a project, so his only option was to purchase a few more wrecked vehicles. The most prominent of these wrecks was nicknamed Slim Shady. This one

had an irreparable shell but with most electronics preserved, and would serve as the donation vehicle. After painstakingly transplanting all the required electronics and once again selling what he did not need, his net investment came to less than 10% of a new car!

Was all of the effort worth it? We certainly think it was! The car was deemed road worthy and even has functioning Super Charging capabilities which according to [Rich] are disabled by Tesla if such a Frankenstein build is detected.

At this point it would probably be instructive to ask [Rich] if he would do it again, but he is already at it, this time salvaging the faster self driving P86. We suggest you stay tuned.

[Thankyou to Enio Fernandes for sending in the tip]

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Tesla Model S Battery Pack Teardown

February 28, 2017 by Jenny List 78 Comments

We’ve heard a lot about the Tesla Model S over the last few years, it’s a vehicle with a habit of being newsworthy. And as a fast luxury electric saloon car with a range of over 300 miles per charge depending on the model, its publicity is deserved, and that’s before we’ve even mentioned ~~autonomous driving~~ driver-assist. Even the best of the competing mass-produced electric cars of the moment look inferior beside it.

Tesla famously build their battery packs from standard 18650 lithium-ion cells, but it’s safe to say that the pack in the Model S has little in common with your laptop battery. Fortunately for those of a curious nature, [Jehu Garcia] has posted a video showing the folks at EV West tearing down a Model S pack from a scrap car, so we can follow them through its construction.

The most obvious thing about this pack is its sheer size, this is a large item that takes up most of the space under the car. We’re shown a previous generation Tesla pack for comparison, that is much smaller. Eye-watering performance and range come at a price, and we’re seeing it here in front of us.

The standard of construction appears to be very high indeed, which makes sense as this is not merely a performance part but a safety critical one. Owners of mobile phones beset by fires will testify to this, and the Tesla’s capacity for conflagration or electrical hazard is proportionately larger. The chassis and outer cover are held together by a huge array of bolts and Torx screws, and as they comment, each one is marked as having been tightened to a particular torque setting.

Under the cover is a second cover that is glued down, this needs to be carefully pried off to reveal the modules and their cells. The coolant is drained, and the modules disconnected. This last task is particularly hazardous, as the pack delivers hundreds of volts DC at a very low impedance. Then each of the sixteen packs can be carefully removed. The packs each contain 444 cells, the pack voltage is 24 V, and the energy stored is 5.3 kWh.

The video is below the break. We can’t help noticing some of the rather tasty automotive objects of desire in their lot.

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