By now, most of you have heard about the winter storm in Virginia that caused a huge traffic jam along Interstate 95 that stranded some people for 24 hours. There were people who claimed that such an event would cause problems for people who drive electric cars such as our Teslas.
Virginia traffic jam
NPR
There's a guy in Michigan who owns two Teslas, a Model X with the old-fashioned electric resistance heating and a Model Y with the newer heat pump heating. He calls himself Dirty Tesla because he lives on a dirt road, and he doesn't wash his cars much. He decided to do an experiment to see how his cars would fare in a traffic jam in cold weather.
Michigan has more than its share of cold weather. He picked a night where the temperature was predicted to vary between twelve and fifteen degrees Fahrenheit. Both cars were charged to 90% at the beginning of the test, and he left them out in his yard overnight, unplugged. He set the cabin temperature of both cars to 70 degrees, and he engaged the driver's seat warmer to level 3, the warmest level.
After 12 hours, both cars were fine. The Model X had used more electricity, but both were capable of going another 12 hours of simulated traffic jam without running out of juice. The car wouldn't last as long if the traffic jam happened when the car was at a lower state of charge, but that same thing would be the case in a gas car if it were stuck in a traffic jam with less than a full tank of gas.
Some of his commenters mentioned that if there were a winter storm that cut off electric power, then electric cars couldn't charge their batteries, but, he pointed out, gas pumps work using electricity. You can't fill your gas tank if the gas station doesn't have electricity.
He mentioned that keeping the car at a lower temperature than 70 degrees would prolong the availability of battery power. He suggested 60 degrees as a reasonable temperature. That's not an issue with a gasoline powered car. Since heat is just a waste product of keeping the engine idling, you can keep the interior of the car as warm as you'd like without using extra gas. One of the things he neglected to mention is that if a gas-powered car is stopped for a long period of time with its engine running, even if it's outside, there's a danger of carbon monoxide poisoning. There's no such danger with an electric car.
Here's some wintertime advice that's appropriate for both an electric car and a gasoline powered car.
He suggested keeping a blanket in the car during the winter. I thought that was such a good idea that I ordered some emergency space blankets to keep in my and my wife's cars. You might also want to keep some food that won't spoil, such as unsalted nuts. Keeping water in the car when you're not in the car is problematic since it could freeze and crack the container, but if you're going on a wintertime trip on a limited-access highway, you should bring some water with you.
Tesla stuck in Virginia traffic
Dan Kanninen, who used to work for the EPA drives a Tesla Model 3. He was caught in the traffic jam for 14 hours. He recently wrote about his experience in Teslarati.
Mr. Kanninen watched Netflix on his touchscreen while waiting for the traffic jam to end. He was comfortable in his car. At the end of the traffic jam, his car, the lowest range Tesla M3, still had 18% charge in it's battery. His car directed him to a supercharger. On the way to the supercharger, he saw long lines of cars waiting for gas stations to fill them up.
He made the point that EV owners who charge at home start each day with their programmed state of charge. That's usually 80% or more. Drivers of gasoline powered cars often start out with less than half a tank.
Tesla’s been on a roll with Supercharger improvements lately, from the 325kW charging update for the Cybertruck, to 500kW with V4 Superchargers coming next year. While those improvements have been limited to the Cybertruck, Tesla didn’t put all their focus on their new flagship vehicle, but looked at their more affordable vehicles as well.
LFP Battery Heating
Tesla’s Superchargers can now heat LFP Batteries - those that are in the Model 3 and Model Y Rear Wheel Drive variants. This applies to Long Range and Standard Range models, which saw a limited run. This is another update included as part of the 2024 Tesla Holiday Update - which really arrived with a lot of unannounced new features and capabilities.
The change is pretty interesting - Superchargers of the V3 and V4 variety can now pre-heat batteries for Model 3 and Model Y vehicles equipped with LFP battery packs. That means those vehicles are able to get back on the road faster when it's extremely cold. Of course, Tesla still advises you to precondition before you arrive, saving drivers time and money.
Max de Zegher, Tesla’s Director of Charging, also commented on the new feature. Essentially, Tesla is inducing an AC (alternating) ripple current through the battery to warm it up. Keep in mind that Superchargers are DC charging. That means it is possible to get a cold-soaked LFP vehicle on the road 4x faster than before, assuming that it didn’t precondition at all and that it is in the worst-case scenario (below 0ºF).
In essence, Tesla is using some engineering magic to turn the circuits inside the LFP battery into an electric heater - and powering that heater through the Supercharger. An AC ripple current is a small oscillation in the DC charging current that generates heat through electrical resistance, warming up the battery. Those ripples are a byproduct of converting AC to DC and back - so Tesla is using the onboard charger to induce those ripples to warm up the battery. Definitely an innovative technique that’s really only possible with the versatility of the NACS connector.
We’re hoping Tesla can implement this across their full lineup of vehicles, but we’ll have to wait and see how it is trialed across LFP vehicles first and if it is even possible on vehicles with 2170 or 4680 battery packs.
Tesla launched two FSD updates simultaneously on Saturday night, and what’s most interesting is that they arrived on the same software version. We’ll dig into that a little later, but for now, there’s good news for everyone. For Hardware 3 owners, FSD V12.6.1 is launching to all vehicles, including the Model 3 and Model Y. For AI4 owners, FSD V13.2.4 is launching, starting with the Cybertruck.
FSD V13.2.4
A new V13 build is now rolling out to the Cybertruck and is expected to arrive for the rest of the AI4 fleet soon. However, this build seems to be focused on bug fixes. There are no changes to the release notes for the Cybertruck with this release, and it’s unlikely to feature any changes when it arrives on other vehicles.
FSD V12.6.1 builds upon V12.6, which is the latest FSD version for HW3 vehicles. While FSD V12.6 was only released for the redesigned Model S and Model X with HW3, FSD V12.6.1 is adding support for the Model 3 and Model Y.
While this is only a bug-fix release for users coming from FSD V12.6, it includes massive improvements for anyone coming from an older FSD version. Two of the biggest changes are the new end-to-end highway stack that now utilizes FSD V12 for highway driving and a redesigned controller that allows FSD to drive “V13” smooth.
It also adds speed profiles, earlier lane changes, and more. You can read our in-depth look at all the changes in FSD V12.6.
Same Update, Multiple FSD Builds
What’s interesting about this software version is that it “includes" two FSD updates, V12.6.1 for HW3 and V13.2.4 for HW4 vehicles. While this is interesting, it’s less special when you understand what’s happening under the hood.
The vehicle’s firmware and Autopilot firmware are actually completely separate. While a vehicle downloading a firmware update may look like a singular process, it’s actually performing several functions during this period. First, it downloads the vehicle’s firmware. Upon unpacking the update, it’s instructed which Autopilot/FSD firmware should be downloaded.
While the FSD firmware is separate, the vehicle can’t download any FSD update. The FSD version is hard-coded in the vehicle’s firmware that was just downloaded. This helps Tesla keep the infotainment and Autopilot firmware tightly coupled, leading to fewer issues.
What we’re seeing here is that HW3 vehicles are being told to download one FSD version, while HW4 vehicles are being told to download a different version.
While this is the first time Tesla has had two FSD versions tied to the same vehicle software version, the process hasn’t actually changed, and what we’re seeing won’t lead to faster FSD updates or the ability to download FSD separately. What we’re seeing is the direct result of the divergence of HW3 and HW4.
While HW3/4 remained basically on the same FSD version until recently, it is now necessary to deploy different versions for the two platforms. We expect this to be the norm going forward, where HW3 will be on a much different version of FSD than HW4. While each update may not include two different FSD versions going forward, we may see it occasionally, depending on which features Autopilot is dependent on.
Thanks to Greentheonly for helping us understand what happened with this release and for the insight into Tesla’s processes.
