We get our first view at hardware 4.0 for the Model Y
Greentheonly/Twitter
In a recent series of fascinating tweets, @greentheonly provided an unprecedented look into the internals of Tesla's new Model Y Hardware 4 or HW4. With his expertise and knowledge, Green shared detailed observations on the HW4's physical structure, board components, and the viability of retrofitting older models, giving the Tesla community much to ponder.
Breaking Down the HW4's Structure
Green's exploration of the HW4's complexities commenced with him acknowledging an "anonymous donor" for providing a chance to look inside Model Y's HW4. The serial numbers and other identifiers were blacked out. Green stated it was done to protect the donor after previous experiences, "Tesla is vengeful like this and went after the guy that did hw2.0 teardown by trying to deny warranty on unrelated repairs. Does not help that this new computer now has a (borderline illegal) 'warranty void if removed' sticker."
First up on the dissection table was the computer's physical form factor. According to Green, the HW4's form factor mirrors those of the S/X models, putting to bed any speculation around a potential retrofit to HW3 cars.
Moving deeper into the HW4, Green revealed that the board layout is similar to the HW4 on the Model S. However, as Green termed it, specific components, including the GPU and superior sound hardware, are now missing or depopulated. The use of cheaper non-Error-Correcting Code ram (ECC RAM) also seems to be a cost-cutting measure implemented by Tesla in this version of HW4 on the infotainment system side. Interestingly, this version of HW4 features two additional but depopulated display connectors, hinting at possible a possible second display in the vehicle.
Other distinguishing attributes of HW4 include a reoriented BroadR-Reach ethernet and the addition of a third, depopulated ethernet. Moreover, Green pointed out that the gateway chip has changed, too, with a different model from another vendor now in use. This chip, which was only seen in Chinese-made boards previously, seems to be a standard feature in all Model Y HW4 boards now.
Retrofitting HW3 to HW4: More Than Meets the Eye
The idea of retrofitting HW3 cars with HW4 stirred up quite a debate. According to Green, the concept may sound enticing, but it's not as straightforward as it seems. Modifying the vehicle to accommodate the new coolant pipe locations would be necessary for a retrofit, likely making this option more costly than simply manufacturing a new board in the old form factor.
Uncovering the Hidden Changes
Apart from the apparent changes, Green shared insights into some of the subtle modifications made by Tesla. For instance, the Texas-manufactured Model Ys feature a plastic "firewall" requiring a change in mounting methods for the new HW4. Despite the internal components remaining the same, the different mounting technique necessitates a unique part number for the computer.
The missing camera connectors were for additional cameras, such as a front bumper camera. However, as Green says, the absence of a connector doesn't mean that Tesla won't add them in the future. In fact, if Tesla had no intentions of adding such features, they wouldn't be available on the board at all, instead of just being unpopulated.
Implications for Current and Prospective Tesla Owners
For existing and future Tesla owners, these findings offer a clearer understanding of what to expect from the HW4-equipped Model Ys. Notably, questions still linger about additional cameras and if and when newer models will receive them. The Cybertruck prototype already has a front bumper camera, so it may only be a matter of time.
While it seems that retrofitting HW3 to HW4 may not be feasible due to the cost and complexity involved, Green isn't entirely ruling out the possibility. He believes a different version could theoretically be created for retrofits, although it's unlikely.
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Alongside the launch of the Cybertruck, Tesla also sneakily launched a new Mobile Connector that came with every Foundation-Series Cybertruck. We initially thought this was just an updated Mobile Connector to match the aesthetics of the Cybertruck, but that’s not the whole story.
New Mobile Connector
This third-gen Mobile Connector has finally arrived in the Tesla Shop, and the old one has been discontinued. Tesla has increased the price of the new connector from $200 USD to $300 USD.
The new Mobile Connector looks like a mini Wall Connector now. It offers the same shape with a green LED running from top to bottom. Otherwise, the packaging and items included are relatively the same, but with one interesting caveat.
Tesla is indicating that the new Mobile Connector can be used with a “Powershare Outlet Adapter” to power electronic devices. While the Outlet Adapter currently isn’t an item available on the Tesla Store, we expect that it will arrive in the coming months.
Unfortunately, Tesla doesn’t have any photos of the Outlet Adapter, but it sounds like it’ll be a different type of plug that connects to the top of the mobile connector, just like the 110V and 220V plugs. Instead of having a male plug to connect to an outlet, it’ll include various outlets at the end.
Powershare Capability for More Teslas?
Another key item of note is that the webpage for the new Mobile Connector also states, “Powershare is currently only available with the Cybertruck”. This appears to indicate that Tesla will soon offer Powershare on other vehicles, potentially the new Model Y, or even older vehicles.
The Cybertruck uses the AC charging circuit to discharge via its 120V and 240V outlets in the bed, which is why you can’t AC charge the truck and use the outlets at the same time.
Differences Between Wall Connector and Mobile Connector
While the Cybertruck is able to use the Powershare capable Wall Connector to power an entire house, the Mobile Connector would be used to power individual devices instead since it’s not capable of the same power output as the Wall Connector.
If and when Tesla brings Powershare to additional vehicles, it’ll be interesting to see whether they also support Powershare Home Backup with a Tesla Gateway or if it’d arrive in a more limited fashion using only the Mobile Connector’s Powershare Outlet Adapter we’re seeing here.
AC power out is a feature of the Cybertruck’s improved power conversion circuit, so it’s not clear whether other vehicles would be able to support this. Tesla could use an inverter to convert the vehicle’s DC power to AC power, which powers household devices.
Even if older vehicles only receive Powershare capabilities through the new Mobile Connector and the Powershare Outlet, this will be a huge win for Tesla owners. While it won’t be able to power an entire home, it should be able to provide about 10 kW of power, which is equivalent to a small gas generator — enough to use power tools, charge devices, run most 110v appliances like a refrigerator, and more.
In the meantime, if you’re itching to use your vehicle’s battery as a massive portable power bank and don’t have the Cybertruck, check out our coverage on the Vortipower V2L VP20 device, which offers similar capabilities by plugging into the NACS port to allow for 120V and 240V power.
Several months ago, Tesla infamously started turning off power to its 12V sockets in its vehicles when someone wasn’t in the vehicle. This affected all vehicles, including the ever-popular Model Y. The reason provided for the removal was inappropriate modification of vehicles to use high-power devices, which could potentially cause dangerous situations.
This left many accessories, such as vehicle fridges, inoperable since they relied on power staying with Sentry Mode.
In its current state, your vehicle disables the rear 12V cigarette lighter-style sockets inside the center console and USB ports, when no one is detected inside the vehicle. The only current workaround to keeping these outlets with power is to use Camp Mode, but this has disadvantages such as the climate system staying on and walk-away locks being turned off.
This change also impacted USB power provided over any of the vehicle’s USB ports. This made it difficult for users to run sub-trunk fridges or other accessories that would continuously draw power, as Camp Mode consumes quite a bit of energy to maintain the vehicle’s internal temperature.
Update: Both the Model Y and Model X include a 12V socket in the rear left pillar of the vehicle, which is located under a flap, alongside a 12V socket in the front of the vehicle. The Model S and Model 3 only include USB ports and a 12V socket in the front.
The Cybertruck is Tesla’s only vehicle with 110V sockets at this time.
Now, in a surprise move, Tesla is restoring access to the 12V sockets when the vehicle is powered off if users enable a new option called “Accessory Power.”
Tesla states that power is available whenever the vehicle detects a user is available or when the Keep Accessory Power On is enabled.
Turning on this new option will enable power across the entire vehicle, including the 12V socket, 12V (max 16A) rear plug (if equipped), and the vehicle’s USB ports. This will let users charge devices or use vehicle accessories, even when they’re not in the vehicle.
This is actually an improvement over the original way to keep these plugs powered without a user present, which required leaving Sentry Mode enabled, which uses a significant portion of energy itself.
The new Accessory Power option will be able to be turned on in your vehicle under Controls > Charging > Keep Accessory Power On.
Limitations
Similar to Sentry Mode and other features, accessory power is only enabled while the option is on and the vehicle’s battery remains above 20%, at which point, it’ll be turned off.
Tesla also warns that keeping the new accessory option on will cause the vehicle to consume additional energy, even if devices are not plugged into any of the outlets, so this should be an option that should be used selectively, when needed.
Release Date
It looks like this feature was supposed to make it out in the 2025.8 update, but to our knowledge, it hasn’t been enabled in any vehicles yet. Our best guess is that it’ll be enabled in a future 2025.8 update, or in the upcoming Spring Update, which will likely add other exciting features — at least if it’s anything like Tesla’s 2024 Spring Update.
We reported back in October that Tesla was looking for alternatives to keep accessories powered on without users present, so we’re super happy to hear this news, as it really shows that Tesla listens to its customers. It’s exciting to see Tesla restore a feature that had a lot of user support behind it, and we’re sure users will be thrilled to be able to use their fridges and accessories again.
If you’re a major user of accessory power, tell us what your primary use case is. Is it charging a laptop while you’re away from your vehicle, or is it running a sub-trunk fridge during your road trips?
We’d love to see some additional input on how Tesla can continue to improve this feature, so let us know in our forums or social media.
