‍Tesla has been in the LFP game for a few years already, using the packs in their Standard Range models worldwide. For the US, this has been mostly the Model 3 SR+, while the rest of the world has had access to LFP-based Standard Range Model Ys, as well. Note that Tesla still uses nickel-based chemistries, mostly NCA (Nickel Cobalt Aluminum Oxide) in their long range and performance models, with some older packs using NMC (Nickel Manganese Cobalt Oxide). 

Looking into 2024, we expect to have more Mustang Mach-Es (VINs with “K3R4”) fitted with LFP packs - we currently have only two such Standard Range in our fleet. The entry-level Fisker Ocean is equipped with them, and the release of LFP Rivians is on the horizon. BMW said it is investing in the technology for release in 2025, and a forward-looking announcement by GM promises LFP packs in the revamped Bolt EV.  

Curious about the politics and cost savings that are inspiring this switch?  

While we wait for all the new LFP models to hit the streets, and our data, Recurrent has been collecting and analyzing our Standard Range Model 3 data to understand how these batteries hold up in the real world. 

But, why is Recurrent so excited about iron phosphate, or LFP, batteries? 

1. The cost savings. LFP batteries are cheaper to produce, and that means more affordable EVs for a wider demographic of shoppers. NCA battery cells clock in at about $120.30 per kWh, NMC at about $112.70/kWh, and LFP as low as $98.50/kWh.
2. Longer life. LFP batteries have a longer cycle life, meaning they can be used from full to empty (or the equivalent thereof), more times than NCA or NMC batteries. 
3. More resistant to aging from fast charging. Although our preliminary Tesla results indicated that occasional fast charging does not have any drastic, short term effect on range, laboratory science has shown us that NCA and NMC batteries are sensitive to long term degradation from frequent high-voltage, high-heat charging. The same is not necessarily true of LFP batteries. This is because LFP batteries rely on a 3-D, crystalline structure, and can withstand high temperatures without decomposing. 
4. Lower fire risk. Lithium ion battery fires are usually due to extreme heat conditions, and are triggered by something called thermal runaway, which happens when the temperature of the pack exceeds a certain limit. For LFP batteries, thermal runaway temperature is at 270 degrees C, as compared to 210 C for NMC and 150 C for NCA. This makes them super safe for on-the-road uses. 

And, while we’re excited about the adoption of more LFP technology, we are scientists, and we do want to mention the compromises that come with using LFP packs. 

1. Lower energy density. LFP batteries give you about 30% less energy in the same sized battery. That means if you want the same range as you had in an NCA powered car, you need to add more batteries, which means more weight and hardware. For some models, this means slightly lower 0-60 acceleration, too.
2. Worse performance in sub-freezing temperatures. Studies have found that based on their composition, LFP batteries have significant issues at low temperatures, including poor conductivity and slow lithium-ion diffusion. In practice, this means poor charge rate when it’s colder than −20 °C (−4 °F). NCM batteries perform significantly better, with increased capacity retention and polarization. However, it is possible that improved and more aggressive thermal management may be able to offset cold weather effects. 

Here, we walk you through some of the other perks of the LFP packs, using preliminary data on over 700 LFP-based Tesla Model 3s, compared to 340 recent year, nickel-based Model 3s in the Recurrent fleet. 

Location of LFP models 

What we see: There is fairly even distribution across the US of LFP and non-LFP battery packs. Since the LFP packs come in the Standard Range models, which are more affordable, they are gaining popularity in a lot of metro areas. 

Why this matters: While no lithium ion batteries love being stored in hot conditions, LFP batteries may hold up better to heat. If you live in a hot climate and know your car will have to be out in the sun, this may be a good consideration when you decide between trim levels. 

Nerdy Aside: Why do LFP batteries promise to be more resistant against heat-related aging and degradation?

Simply put, the Fe-PO bond in LFP compositions is stronger than the Co-O bond in cobalt-based batteries, so that if abused (short-circuited, overheated, etc.) the oxygen atoms are much harder to remove. This means that under stress, a LFP battery is more likely to resist rapid rises in temperature, which can result in permanent battery damage or in dire cases - start a fire. 

Cold Weather

The other consideration is cold weather. While we don’t see a ton of any Model 3s in the extremely cold regions of the US just yet, there are questions about how well the packs charge in very cold (below freezing) temperatures below −20 °C (−4 °F). But, although charge rate in super cold temperatures will be affected, LFP performance and power while driving should not be.

Reviewers and testers in Canada, Norway, and other icy climates report that range loss, even with preconditioning, can be a few percentage points above what is seen with NCA Model 3s. Warming the batteries enough to fast charge may also take longer for LFPs. 

Maximum Charge Rate

What we see: Tesla drivers with LFP batteries in their cars charge beyond 90% far more than Tesla drivers with non-LFP batteries. Most non-LFP models are kept between 50% and 90% state of charge, while most LFP vehicles are charged between 90% and 100%. 

Why this matters: LFP batteries hold up better to high states of charge, meaning that regularly charging them to 100% may not cause as much degradation as it would with a different battery chemistry. 

So...Charge to 100% or 80%?

One of the most frequent charging questions we get is from LFP Tesla owners who are curious about why our charging guidance seems to conflict with Tesla’s charging guidance. While Recurrent recommends trying to keep all batteries between 30% and 80% state of charge, Tesla tells LFP drivers it’s OK to charge to 100% for daily drives, and recommends doing so at least once a week.

Why the discrepancy? Two things:

1. LFP chemistries are known to hold up better to high charges than NCA or NMC batteries. This means that an LFP battery charged regularly to 100% will, over time, degrade less than a different battery treated the same way. Since LFP batteries have lower energy density, the extra bit of charge means an equivalent range for cars with these packs. However, for all lithium ion batteries, avoiding a full charge will prolong life. It’s just that it may not be as noticeable a change with LFP packs.  
2. Tesla’s battery management system (BMS) will be more accurate if it can recalibrate at 100% state of charge. This is true for all Teslas, but particularly true for LFP models. Why? LFP batteries have a very flat voltage curve, which means that it’s harder for them to calibrate at 80% than it is to calibrate an NCA battery at 80%. Read on to understand more about this.

Nerdy aside: Why a flat voltage curve makes the BMS job’s harder

With NCA batteries, the voltage increases pretty linearly as the state of charge increases, and decreases as the state of charge decreases. That means the BMS can use voltage information, which is relatively easy to check, to estimate the state of charge. However, in an LFP battery, the voltage does not vary as much with state of charge. This makes it harder to use voltage as a predictor, especially when it comes to individual cells. By charging to 100% periodically, the BMS has a “set point” to recalibrate its capacity prediction, and hence the accuracy of its range estimates. 

Real Range 

What’s the takeaway? After some very public investigation this year, the world learned that the displayed dashboard range for most Teslas is higher than the actual, achievable range that the same cars actually get. Recurrent came up with a proprietary value, Real Range, to show the typical, achievable range we observe for an average Tesla. The chart above shows how much of the EPA range Teslas usually get, and the temperature dependence of this value. 

What we see, at least for Tesla Model 3s, is two-fold:

1. The peak range seems to happen at a higher temperature for LFP batteries as compared to non-LFP batteries, and
2. The LFP models seem to get a higher percentage of their EPA range than the non-LFP vehicles. 

Both of these results are exciting, although preliminary. They show differences in the ideal operating temperature for LFP batteries, which seem to get the highest range at around 70 degrees, compared to around 60 degrees for NCA packs. 

They also show that the EPA range advertised for the Standard Range Model 3s is slightly closer to the truth than it is for the Long Range and Performance models. It’s important for Tesla drivers to know what their actual, achievable range is in the real world, in order to understand the limits and possibilities of their car. Of course, as we like to say with all things range, Your Mileage May Vary - and we’d love to hear your experience with your LFP battery!