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

August 31, 2021

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’s Sentry Mode Will Soon Play Music at Max Volume When Triggered

March 21, 2025

By Karan Singh

Not a Tesla App

Following Tesla’s Q1 2025 All-Hands Meeting, the company quietly updated the Cybertruck’s webpage. When we first checked it during our Live Space, nothing immediately stood out. At first glance, the changes seemed to be mostly stylistic—aligning the page’s format with the rest of Tesla’s site while adding a Cyber-inspired twist with unique fonts and boxed media elements.

But this morning, we took a closer look—because if there’s one thing Tesla loves, it’s hiding details in plain sight. And sure enough, we found an interesting change around Sentry Mode — playing loud music.

Sentry Mode Music

Tesla quietly updated the Sentry Mode section on the Cybertruck’s about page, adding new text that reveals Sentry Mode will soon be able to play loud music when it’s triggered. The text on Tesla’s site states:

“Enable Sentry Mode to monitor your unattended vehicle or trailer, and automatically activate the alarm, increase the touchscreen brightness, and play music at max volume if a threat is detected.”

That last detail—playing music at max volume—is a brand-new addition to Sentry Mode. Tesla has already expanded Sentry’s coverage to also cover attached trailers and previously announced that the system may soon honk in response to vandalism.

This latest change appears to build on that, leveraging the Cybertruck’s Superhorn and external speaker, which can already play music when parked via the Boombox feature. We suspect this feature won’t rely on the internal speakers, as the music would have to be extremely loud in order to be heard outside the car.

And given how loud the Superhorn and external speakers are—powerful enough to function as a proper horn—this could be an effective deterrent for vandals or intruders.

Other Models Too?

While this feature was spotted on the Cybertruck’s page, it’s unlikely that it’ll be exclusive to the stainless steel beast. We did a quick scan of Tesla’s other vehicle pages, but the change hasn’t made it over to other pages yet. While Tesla’s other vehicles don’t include the Superhorn, most are equipped with an external speaker for the Pedestrian Warning System (PWS)—which also powers the Boombox feature.

If your Tesla supports Boombox, it’s likely that Sentry Mode Music will roll out across the lineup once the update is released. However, legacy vehicles without a PWS will likely miss out on this feature.

When Will It Be Released?

To answer everyone’s favorite question, we know it’s not in Tesla’s 2025.8 update, which has recently started rolling out. Given the small 2025 releases so far (2025.2 and 2025.8), Tesla may be preparing a larger 2025 Spring Update similar to last year’s.

We’re about a month away from the arrival of Tesla’s Spring Update, and this could be one of the included features.

The real question is: Will Tesla allow custom sounds or music via USB? If so, the possibilities just got a whole lot more entertaining.

New 'Wile E. Coyote' Wall Video Puts Tesla's FSD V13 to the Test

March 21, 2025

By Karan Singh

Not a Tesla App

Last week, Mark Rober, an engineering YouTuber best known for his glitter bombs, released a video where he tested Tesla's Autopilot against various conditions - including the iconic ACME painted wall.

During this test, many people noted that Mark was using Autopilot rather than FSD, even though his video was titled “Can you Fool a Self-Driving Car?”. The Tesla on Autopilot went up against a vehicle equipped with Luminar’s LIDAR rig, running some sort of basic autonomy or safety software.

New Video Tests FSD

Many people were disappointed with Mark’s video and his testing methods, so several creators got to work to actually test out Tesla’s FSD.

Creator Kyle Paul over on X made a much better follow-up video, using both a HW3 Model Y as well as an AI4 Cybertruck. In a relatively unsurprising turn of events, the Cybertruck was successfully able to detect the wall, slowed down, and came to a stop. The Cybertruck was running FSD 13.2.8.

Kyle’s team did a fantastic job building the wall and testing this in a private area using FSD rather than Autopilot. On top of that - they re-tested the results several times and recorded the entire thing in and out. While Mark’s video was more for entertainment, Kyle really set out to prove what would really happen in this unlikely scenario.

Sadly, the HW3 Model Y was unable to detect the wall, and manual intervention was required in each test. While the Model Y was running FSD 12.5.4.2 rather than an FSD V12.6 build, we don’t expect this to have had a significant impact on the test - this is more of an issue with how computer vision analyzes the environment.

There are several major differences between HW3 and HW4. The first is obviously that the version that runs on AI4 is more advanced, as the hardware is capable of processing a lot more data. However, AI4 also features much higher-resolution cameras than HW3, and Tesla recently added the ability for the video feeds to be processed at full resolution on FSD V13. This could have made the difference, although it’s not entirely clear. Perhaps if HW3 gets a version of FSD V13 in the future, HW3 can be retested to see if it passes the “ACME wall” test.

Watch

Kyle’s entire video is below. It’s only 10 minutes long, so definitely give it a watch. Props to Kyle on the quick and thorough execution.

What Does This Mean for FSD?

We broke down Mark’s test - and examined all the little issues that we discovered after doing some in-depth research - you can read our analysis here.

Putting aside the issues with Mark’s testing and instead using the new results - it seems that if you were to have to fight against Wile-E-Coyote and his ACME tools with your Tesla, cartoon logic may win if you’re on an HW3 vehicle. If you’re on an AI4 vehicle, you’ll likely come to a safe stop.

Vehicle depth perception is definitely something that Tesla has been hard at work to improve - and some fairly drastic improvements came with FSD V13 that haven’t been entirely translated to FSD V12 just yet. Future versions of HW3 FSD may be able to determine that the wall is there successfully. So Kyle - if you’re reading this - don’t get rid of that wall. We’d love to see more testing in the future.

However, this entire test scenario is so out of left field… there is a good likelihood this same test would fool some human drivers as well. The most important part is that the future of autonomy will not fall for these tricks, so it's very unlikely for someone to weaponize this idea as it’d only possibly work on a small segment of vehicles.

If Wile-E-Coyote is after you, someone else may drive into the wall before your Tesla does.

Not a Tesla App

We’re not kidding, this really happened already. This isn’t a realistic scenario outside of someone trying to play an insane prank - but it’s good to know that FSD V13 is capable of dodging this.