If you ever doubt the potential for catastrophe that mucking about with electric vehicles can present, check out the video below. It shows what can happen to a couple of Tesla battery modules when due regard to safety precautions isn’t paid.
The video comes to us by way of [Rich], a gearhead with a thing for Teslas. He clearly knows his way around the EV world, having rebuilt a flood-soaked Tesla, and aspires to open an EV repair shop. The disaster stems from a novelty vehicle he and friend [Lee] bought as a side project. The car was apparently once a Disney prop car, used in parades with the “Mr. Toad’s Wild Ride” theme. It was powered by six 6-volt golf cart batteries, which let it maintain a stately, safe pace on a crowded parade route. [Rich] et al would have none of that, and decided to plop a pair of 444-cell Tesla modules into it. The reduced weight and increased voltage made it a real neck-snapper, but the team unwisely left any semblance of battery management out of the build.
You can guess what happened next, or spin up to the 3:00 mark in the video to watch the security camera mayhem. It’s not clear what started the fire, but the modules started cooking off batteries like roman candles. Quick action got it pushed outside to await the fire department, but the car was a total loss long before they showed up. Luckily no other cars in the garage were damaged, nor were there any injuries – not that the car didn’t try to take someone out, including putting a flaming round into [Lee]’s chest and one into the firetruck’s windshield.
[Rich] clearly knew he was literally playing with fire, and paid the price. The lesson here is to respect the power of these beefy batteries, even when you’re just fooling around.
When referring to classic cars, there’s a good reason that “they don’t make ’em like that anymore.” Old cars represented the limits of what could be done in terms of materials and manufacturing methods coupled with the styles of the time and cheap fuel. The result was big, heavy cars that would cost a fortune in gas to keep on the road today.
Some people just don’t want to let those styles go, however, and send their beast off for some special modifications. This 1949 Mercury coupe with an electric drivetrain conversion is one way of keeping that retro look alive. Granted, the body of the car is not exactly showroom quality anymore, from the light patina of rust on its heavy steel body panels to the pimples cropping up under its abundant chrome. But that’s all part of the charm; this comes from conversion company Icon’s “Derelict” line, which takes old vehicles and guts them while leaving the outside largely untouched. This Mercury was given a fully electric, 298 kW drivetrain. The engine bay and trunk, together roomier than some Silicon Valley studio apartments, provided ample room for the 85 kWh Tesla battery pack and the dual electric motors, with room left over to craft enclosures for the battery controllers that look like a V8 engine. Custom electronic gauges and controls that look like originals adorn the chrome-bedazzled dash. The beast tops out at 120 mph (193 km/h) and has a 200 mile (322 km) range before it has to find a Tesla supercharger. Or a lemonade stand.
Say what you want about the old cars, but they had plenty of style. We appreciate the work that went into this conversion, which no doubt cost more than all the gas this thing has ever guzzled.
In one bad week in March, two people were indirectly killed by automated driving systems. A Tesla vehicle drove into a barrier, killing its driver, and an Uber vehicle hit and killed a pedestrian crossing the street. The National Transportation Safety Board’s preliminary reports on both accidents came out recently, and these bring us as close as we’re going to get to a definitive view of what actually happened. What can we learn from these two crashes?
There is one outstanding factor that makes these two crashes look different on the surface: Tesla’s algorithm misidentified a lane split and actively accelerated into the barrier, while the Uber system eventually correctly identified the cyclist crossing the street and probably had time to stop, but it was disabled. You might say that if the Tesla driver died from trusting the system too much, the Uber fatality arose from trusting the system too little.
But you’d be wrong. The forward-facing radar in the Tesla should have prevented the accident by seeing the barrier and slamming on the brakes, but the Tesla algorithm places more weight on the cameras than the radar. Why? For exactly the same reason that the Uber emergency-braking system was turned off: there are “too many” false positives and the result is that far too often the cars brake needlessly under normal driving circumstances.
The crux of the self-driving at the moment is precisely figuring out when to slam on the brakes and when not. Brake too often, and the passengers are annoyed or the car gets rear-ended. Brake too infrequently, and the consequences can be worse. Indeed, this is the central problem of autonomous vehicle safety, and neither Tesla nor Uber have it figured out yet.
The Tesla Model 3 has been available for almost a year now, and hackers and tinkerers all over the world are eager to dig into Elon’s latest ride to see what makes it tick. But while it’s considerably cheaper than the Model S that came before it, the $35,000+ USD price tag on the new Tesla is still a bit too high to buy one just to take it apart. So for budget conscious grease monkeys, the only thing to do is wait until somebody with more money than you crashes one and then buy the wreckage cheaply.
Which is exactly what electric vehicle connoisseur [Jack Rickard] did. He bought the first wrecked Model 3 he could get his hands on, and proceeded to do a lengthy teardown on what’s arguably the heart and soul of the machine: its 75 kWh battery pack. Along the way he made some interesting discoveries, and gained some insight on to how Tesla has been able to drop the cost of the Model 3 so low compared to their previous vehicles.
On a Tesla, the battery pack is a large flat panel which takes up effectively the entire underside of the vehicle. To remove it, [Jack] and his assistant raise the wreck of the Model 3 up on a standard lift and then drop the battery down with a small lift table. Here the first differences are observed: while the Model S battery was made for rapid swapping (a feature apparently rarely utilized in practice), the battery in the Model 3 battery is obviously intended to be a permanent piece of the car; removing it required taking out a good portion of the interior.
With the battery out of the car and opened up, the biggest change for the Model 3 becomes apparent. The battery pack actually contains the charger, DC-DC converter, and battery management system in one integrated unit. Whereas on the Model S these components were installed in the vehicle itself, on the Model 3, most of the primary electronics are stored in this single module.
That greatly reduces the wiring and complexity of the car, and [Jack] mentions the only significant hardware left inside the Model 3 (beyond the motors) would be the user interface computer in the dashboard. When the communication protocol for this electronics module is reverse engineered, it may end up being exceptionally useful for not only electric vehicle conversions but things like off-grid energy storage.
In two weeks the Hackaday Community is gathering in Belgrade for Europe’s greatest hardware con, The Hackaday Belgrade Conference — an event not to be missed — but of course the city itself is a spectacular place to visit and has the perfect feel for those who like to build electronics. Why not join us for your own geek world tour to Serbia? Here’s a few of the things you’ll want to see while in Belgrade.
Aircraft, Inventor, Architecture
Belgrade is a tech center and a hidden jewel of Europe. Need proof? Fly into Belgrade, and you’ll land at Nikola Tesla Airport. Pick up a car at the airport and you’ll pass a great glass torus housing Serbia’s Museum of Aviation. Here, you’ll find aircraft from both sides of the cold war, Sabres and MiGs, Hurricanes and Messerschmitts, a quite rare Sud Caravelle, and the canopy of the only stealth bomber ever to be shot down. It’s an aviation geek’s paradise, and you haven’t even left the airport.
What else is in store for you when you visit Belgrade? For the Hackaday crowd, the most interesting bit will probably be the Nikola Tesla Museum. You might know of Nikola Tesla from a webcomic, but he’s actually the greatest inventor of all time, even more so than Elon Musk. Tesla invented radio, even though Marconi got the credit. Tesla invented radar and discovered x-rays. The only person they could find to portray a figure like Tesla in The Prestige was David Bowie. Nikola Tesla is the most iconic inventor to ever live (change my mind), and his museum is in Belgrade.
Self-driving cars have been in the news a lot in the past two weeks. Uber’s self-driving taxi hit and killed a pedestrian on March 18, and just a few days later a Tesla running in “autopilot” mode slammed into a road barrier at full speed, killing the driver. In both cases, there was a human driver who was supposed to be watching over the shoulder of the machine, but in the Uber case the driver appears to have been distracted and in the Tesla case, the driver had hands off the steering wheel for six seconds prior to the crash. How safe are self-driving cars?
Trick question! Neither of these cars were “self-driving” in at least one sense: both had a person behind the wheel who was ultimately responsible for piloting the vehicle. The Uber and Tesla driving systems aren’t even comparable. The Uber taxi does routing and planning, knows the speed limit, and should be able to see red traffic lights and stop at them (more on this below!). The Tesla “Autopilot” system is really just the combination of adaptive cruise control and lane-holding subsystems, which isn’t even enough to get it classified as autonomous in the state of California. Indeed, it’s a failure of the people behind the wheels, and the failure to properly train those people, that make the pilot-and-self-driving-car combination more dangerous than a human driver alone would be.
You could still imagine wanting to dig into the numbers for self-driving cars’ safety records, even though they’re heterogeneous and have people playing the mechanical turk. If you did, you’d be sorely disappointed. None of the manufacturers publish any of their data publicly when they don’t have to. Indeed, our glimpses into data on autonomous vehicles from these companies come from two sources: internal documents that get leaked to the press and carefully selected statistics from the firms’ PR departments. The state of California, which requires the most rigorous documentation of autonomous vehicles anywhere, is another source, but because Tesla’s car isn’t autonomous, and because Uber refused to admit that its car is autonomous to the California DMV, we have no extra insight into these two vehicle platforms.
Nonetheless, Tesla’s Autopilot has three fatalities now, and all have one thing in common — all three drivers trusted the lane-holding feature well enough to not take control of the wheel in the last few seconds of their lives. With Uber, there’s very little autonomous vehicle performance history, but there are leaked documents and a pattern that makes Uber look like a risk-taking scofflaw with sub-par technology that has a vested interest to make it look better than it is. That these vehicles are being let loose on public roads, without extra oversight and with other traffic participants as safety guinea pigs, is giving the self-driving car industry and ideal a black eye.
If Tesla’s and Uber’s car technologies are very dissimilar, the companies have something in common. They are both “disruptive” companies with mavericks at the helm that see their fates hinging on getting to a widespread deployment of self-driving technology. But what differentiates Uber and Tesla from Google and GM most is, ironically, their use of essentially untrained test pilots in their vehicles: Tesla’s in the form of consumers, and Uber’s in the form of taxi drivers with very little specific autonomous-vehicle training. What caused the Tesla and Uber accidents may have a lot more to do with human factors than self-driving technology per se.
You can see we’ve got a lot of ground to cover. Read on!
What kind of power service is in the United States? You probably answered 120-volt service. If you thought a little harder, you might remember that you have some 240-volt outlets and that some industrial service is three phase. There used to be DC service, but that was a long time ago. That’s about it, right? Turns out, no. There are a very few parts of the United States that have two-phase power. In addition, DC didn’t die as quickly as you might think. Why? It all boils down to history and technological inertia.
You probably have quite a few 120-volt power jacks in sight. It is pretty hard to find a residence or commercial building these days that doesn’t have these outlets. If you have a heavy duty electric appliance, you may have a 240-volt plug, too. For home service, the power company supplies 240 V from a center tapped transformer. Your 120V outlets go from one side to the center, while your 240V outlets go to both sides. This is split phase service.
Industrial customers, on the other hand, are likely to get three-phase service. With three-phase, there are three wires, each carrying the line voltage but out of phase with each other. This allows smaller conductors to carry more power and simplifies motor designs. So why are there still a few pockets of two-phase?