Tesla's LFP (iron) batteries compared. Which one should you buy?

By Henry Farkas

For the first time, you have a choice of battery for your new Tesla. Not battery size, you've always had that choice. Now you have a choice of which chemical elements you want. Here are some thoughts about how you can choose intelligently. It all depends on your financial situation, your plans for long-distance travel, and the geography of your area.

Tesla's Iron and Nickel based batteries

Elon Musk explains Tesla's LFP Battery strategy for US Model 3 SR+.

There's a delay in delivery times for the Model 3 SR+. This is August 2021. Delivery dates are some time in 2022. If you're buying one of the more expensive models or one of the bigger battery sizes, you can take delivery sooner, but the Model 3 SR+ might be the one you want. It's the one I bought. I knew that road trips would take a bit longer with the shorter-range battery since I'd have to pull off the road to charge more often. So far, I haven't had the opportunity to take a multi-day road trip. There's a pandemic after all. But I knew that would eventually become an issue. I really like road trips. But I have to say, even when I took lots of road trips, most of my driving was local.

Had I opted for the long-range Model 3, I'd have paid an extra ten thousand dollars in order to get 90 miles of extra range. That extra ninety miles of range would come into play only 30 or 40 days each year, and the time it would save me would be about an hour each day of a multi-day road trip. It didn't make financial sense.

Now that Tesla is experiencing the same production delays as are all the other auto manufacturers, they're giving their shorter delivery dates to buyers of the more expensive, read higher profit, models. But they're making an exception and giving shorter delivery dates if you buy a Tesla with an LFP battery rather than an NCA battery.

So what's the difference? Both batteries are actually lithium-ion batteries. They both use lithium. So that's not a difference. But the NCA battery uses nickel, cobalt, and aluminum in addition to lithium. The LFP battery uses Iron and Phosphate (phosphorus combined with oxygen) in addition to lithium. The main differences for you to consider are that the LFP battery has a slightly shorter range, 253 miles, as opposed to the NCA battery, 263 miles. But that slight difference in range is deceptive. The NCA battery probably shouldn't be charged to 100%. Fully charging the battery causes damage to the battery making it likely to deteriorate over the years of ownership. It's perfectly fine to charge the LFP battery to 100% so the driver experience is pretty much the same except for a couple caveats.

Iron and Nickel based batteries cost comparison

The LFP battery is heavier. That's why the range is slightly lower on the ordinary battery test cycle. The extra weight causes extra rolling resistance. That's why the range is reduced. There's probably also some extra wear on the tires. The problems of extra weight and extra rolling resistance are probably not all that bothersome for most drivers.

But, if you live in an area where there are lots of hills so that you're changing your elevation every time you drive, you're going to notice a much more pronounced decrease in range with the heavier LFP battery. You can experience the difference more intimately by getting a wagon or a wheelbarrow. Roll it around on level ground. Then put a heavy object in it and roll it around some more. You'll notice a bit more rolling resistance, but you'll be able to deal with the extra rolling resistance easily.

Now do that same experiment on a hill. Pull the wagon or push the wheelbarrow up the hill empty. No problem, right? Then put in the heavy object and go up the hill again. Big difference. Your car feels the same way. You'll get a bit of extra regenerative braking going down the hill with the heavier battery, but it won't be enough to make up the difference. The second law of thermodynamics causes that. That pesky high school physics topic, entropy, strikes again.

LFP batteries are also much more environmentally friendly.

There's also one more issue, cold weather.

LFP batteries charge more slowly in cold weather than NCA batteries and their range decreases somewhat more than NCA batteries in cold weather. Keep in mind that both NCA and LFP do worse in cold weather. It's just that LFP batteries get more of a cold weather effect than NCA batteries. When you're on a road trip and navigating to a Supercharger, your car will prewarm its batteries. That will alleviate the slower charging problem to some extent, but you'll be at the Supercharger six or seven minutes longer in winter with LFP batteries. That will be a problem if you plan to use your car in such a way as to need to do lots of cold weather supercharging. It won't matter at all if you're just going to charge your car overnight in your garage.

So flatlanders will be fine with the LFP battery. If you live in a hilly area, you may want to wait for the NCA-equipped Tesla Model 3 SR+. But remember, the lower range problem is only a problem for people planning to do lots of mountain driving. In that case, you actually ought to invest the extra $10K in the long range Model 3.

One last issue about the LFP battery. Remember, earlier in this article, I mentioned that you shouldn't fill the NCA battery up to 100% charge, but you should fill the LFP battery up to 100%? That's true at home, but it's not true on road trips. On road trips, you want to minimize the amount of time you're stopped. The way to do that is to never charge the battery to 100% no matter which kind of battery you have. When you plug your car in at a modern high voltage supercharger, you'll see your car adding four to five hundred miles per hour of connection. That doesn't mean you'll be up to 100% in a half hour. You won't. As the battery gets charged, the rate of charge drops significantly for both the LFP and the NCA batteries. Once you get above 80%, the battery charges very slowly. So figure out how much charge you need to get you to the next place you're going to charge up and give yourself enough charge to get you there with a twenty or thirty mile cushion. Charging your battery more than that is a waste of time. Your travel time.

Tesla's Battery Day

Tesla Holiday Update Wishlist - Charging & Safety Edition

By Karan Singh
Not a Tesla App

As December approaches, Tesla’s highly anticipated Holiday update draws closer. Each year, this eagerly awaited software release transforms Tesla vehicles with new features and festive flair. If you’re not familiar with Tesla’s holiday updates, take a look at what Tesla has launched in the Holiday update the past few years.

While leaked features like Blind Spot Monitoring While Parked hint at thoughtful improvements, the real magic lies in the unexpected. From potential features such as the Apple Watch app to a smart assistant, the possibilities are endless.

For this chapter in our series, we’re dreaming up ways Tesla could improve the charging experience and even add some additional safety features. So let’s take a look.

Destination State of Charge

Today, navigating to a destination is pretty straightforward on your Tesla. Your vehicle will automatically let you know when and where to charge, as well as for how long. However, you’ll likely arrive at your destination at a low state of charge.

Being able to set your destination state of charge would be an absolute game-changer for ease of road-tripping. After all, the best EV to road trip in is a Tesla due to the Supercharger network. It looks like Tesla may be listening. Last week, Tesla updated their app and hinted at such a feature coming to the Tesla app. A Christmas present, maybe?

Battery Precondition Options

While Tesla automatically preconditions your battery when needed for fast charging, there are various situations where manually preconditioning the battery would be beneficial.

Currently, there is no way to precondition for third-party chargers unless you “navigate” to a nearby Supercharger. If you need to navigate to a Supercharger that’s close by, the short distance between your location and the Supercharger will also not allow enough time to warm up the battery, causing slower charging times.

In Europe, you can navigate to and precondition for Qualified Third Party Chargers, but not for unlabelled ones.

Live Activities

While we already mentioned Live Activities in the Tesla app wishlist, they’d be especially useful while Supercharging. Live Activities are useful for short-term information you want to monitor, especially if it changes often — which makes them perfect for Supercharging, especially if you want to avoid idle fees.

Vehicle-to-Load / Vehicle-to-Home Functionality

The Cybertruck introduced Tesla Power Share, Tesla’s name for Vehicle-to-Home functionality (V2H). V2H allows an EV to supply power directly to a home. By leveraging the vehicle’s battery, V2H can provide backup power during outages and reduce energy costs by using stored energy during peak rates.

Tesla Power Share integrates seamlessly with Tesla Energy products and the Tesla app. We’d love to see this functionality across the entire Tesla lineup. Recently a third party demonstrated that bidirectional charging does work on current Tesla vehicles – namely on a 2022 Model Y.

Adaptive Headlights for North America

While Europe and China have had access to the Adaptive Headlights since earlier this year, North America is still waiting. The good news is that Lars Moravy, VP of Vehicle Engineering, said that these are on their way soon.

Blind Spot Indication with Ambient Lighting

Both the 2024 Highland Model 3 Refresh and the Cybertruck already have ambient lighting features, but they don’t currently offer a practical purpose besides some eye candy. So why not integrate that ambient lighting into the Blindspot Warning system so that the left or right side of the vehicle lights up when there’s a vehicle in your blind spot? Currently, only a simple red dot lights up in the front speaker grill, and the on-screen camera will also appear with a red border when signaling.

Having the ambient lighting change colors when a vehicle is in your blind spot would be a cool use of the technology, especially since the Model Y Juniper Refresh and Models S and X are supposed to get ambient lighting as well.

Tesla’s Holiday update is expected to arrive with update 2024.44.25 in just a few short weeks. We’ll have extensive coverage of its features when it finally arrives, but in the meantime, be sure to check out our other wishlist articles:

How Tesla’s “Universal Translator” Will Streamline FSD for Any Platform

By Karan Singh
Not a Tesla App

It’s time for another dive into how Tesla intends to implement FSD. Once again, a shout out to SETI Park over on X for their excellent coverage of Tesla’s patents.

This time, it's about how Tesla is building a “universal translator” for AI, allowing its FSD or other neural networks to adapt seamlessly to different hardware platforms.

That translating layer can allow a complex neural net—like FSD—to run on pretty much any platform that meets its minimum requirements. This will drastically help reduce training time, adapt to platform-specific constraints, decide faster, and learn faster.

We’ll break down the key points of the patents and make them as understandable as possible. This new patent is likely how Tesla will implement FSD on non-Tesla vehicles, Optimus, and other devices.

Decision Making

Imagine a neural network as a decision-making machine. But building one also requires making a series of decisions about its structure and data processing methods. Think of it like choosing the right ingredients and cooking techniques for a complex recipe. These choices, called "decision points," play a crucial role in how well the neural network performs on a given hardware platform.

To make these decisions automatically, Tesla has developed a system that acts like a "run-while-training" neural net. This ingenious system analyzes the hardware's capabilities and adapts the neural network on the fly, ensuring optimal performance regardless of the platform.

Constraints

Every hardware platform has its limitations – processing power, memory capacity, supported instructions, and so on. These limitations act as "constraints" that dictate how the neural network can be configured. Think of it like trying to bake a cake in a kitchen with a small oven and limited counter space. You need to adjust your recipe and techniques to fit the constraints of your kitchen or tools.

Tesla's system automatically identifies these constraints, ensuring the neural network can operate within the boundaries of the hardware. This means FSD could potentially be transferred from one vehicle to another and adapt quickly to the new environment.

Let’s break down some of the key decision points and constraints involved:

  • Data Layout: Neural networks process vast amounts of data. How this data is organized in memory (the "data layout") significantly impacts performance. Different hardware platforms may favor different layouts. For example, some might be more efficient with data organized in the NCHW format (batch, channels, height, width), while others might prefer NHWC (batch, height, width, channels). Tesla's system automatically selects the optimal layout for the target hardware.

  • Algorithm Selection: Many algorithms can be used for operations within a neural network, such as convolution, which is essential for image processing. Some algorithms, like the Winograd convolution, are faster but may require specific hardware support. Others, like Fast Fourier Transform (FFT) convolution, are more versatile but might be slower. Tesla's system intelligently chooses the best algorithm based on the hardware's capabilities.

  • Hardware Acceleration: Modern hardware often includes specialized processors designed to accelerate neural network operations. These include Graphics Processing Units (GPUs) and Tensor Processing Units (TPUs). Tesla's system identifies and utilizes these accelerators, maximizing performance on the given platform.

Satisfiability

To find the best configuration for a given platform, Tesla employs a "satisfiability solver." This powerful tool, specifically a Satisfiability Modulo Theories (SMT) solver, acts like a sophisticated puzzle-solving engine. It takes the neural network's requirements and the hardware's limitations, expressed as logical formulas, and searches for a solution that satisfies all constraints. Try thinking of it as putting the puzzle pieces together after the borders (constraints) have been established.

Here's how it works, step-by-step:

  1. Define the Problem: The system translates the neural network's needs and the hardware's constraints into a set of logical statements. For example, "the data layout must be NHWC" or "the convolution algorithm must be supported by the GPU."

  2. Search for Solutions: The SMT solver explores the vast space of possible configurations, using logical deduction to eliminate invalid options. It systematically tries different combinations of settings, like adjusting the data layout, selecting algorithms, and enabling hardware acceleration.

  3. Find Valid Configurations: The solver identifies configurations that satisfy all the constraints. These are potential solutions to the "puzzle" of running the neural network efficiently on the given hardware.

Optimization

Finding a working configuration is one thing, but finding the best configuration is the real challenge. This involves optimizing for various performance metrics, such as:

  • Inference Speed: How quickly the network processes data and makes decisions. This is crucial for real-time applications like FSD.

  • Power Consumption: The amount of energy used by the network. Optimizing power consumption is essential for extending battery life in electric vehicles and robots.

  • Memory Usage: The amount of memory required to store the network and its data. Minimizing memory usage is especially important for resource-constrained devices.

  • Accuracy: Ensuring the network maintains or improves its accuracy on the new platform is paramount for safety and reliability.

Tesla's system evaluates candidate configurations based on these metrics, selecting the one that delivers the best overall performance.

Translation Layer vs Satisfiability Solver

It's important to distinguish between the "translation layer" and the satisfiability solver. The translation layer is the overarching system that manages the entire adaptation process. It includes components that analyze the hardware, define the constraints, and invoke the SMT solver. The solver is a specific tool used by the translation layer to find valid configurations. Think of the translation layer as the conductor of an orchestra and the SMT solver as one of the instruments playing a crucial role in the symphony of AI adaptation.

Simple Terms

Imagine you have a complex recipe (the neural network) and want to cook it in different kitchens (hardware platforms). Some kitchens have a gas stove, others electric; some have a large oven, others a small one. Tesla's system acts like a master chef, adjusting the recipe and techniques to work best in each kitchen, ensuring a delicious meal (efficient AI) no matter the cooking environment.

What Does This Mean?

Now, let’s wrap this all up and put it into context—what does it mean for Tesla? There’s quite a lot, in fact. It means that Tesla is building a translation layer that will be able to adapt FSD for any platform, as long as it meets the minimum constraints.

That means Tesla will be able to rapidly accelerate the deployment of FSD on new platforms while also finding the ideal configurations to maximize both decision-making speed and power efficiency across that range of platforms. 

Putting it all together, Tesla is preparing to license FSD, Which is an exciting future. And not just on vehicles - remember that Tesla’s humanoid robot - Optimus - also runs on FSD. FSD itself may be an extremely adaptable vision-based AI.

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