New Study Raises Questions About LFP Battery Charging Habits

Lithium Iron Phosphate (LFP) batteries have been the go-to option for many electric vehicles, known for their durability, safety, and cost-effectiveness. For years, automakers like Tesla have encouraged drivers to regularly charge their LFP-equipped vehicles to 100% without fear of significant battery degradation. But a new study is shaking up that advice, suggesting that full charges might not be as harmless as once believed.

The LFP’s big advantage—or is it?

LFP batteries have long been touted as a more robust alternative to traditional nickel-based batteries, like nickel manganese cobalt (NMC) packs. They’re cheaper, pose a lower fire risk, and generally last longer. That’s why you’ll find them in entry-level EVs like the rear-wheel-drive Tesla Model 3 and the base Ford Mustang Mach-E. Automakers have consistently recommended charging these batteries to 100% to keep range estimates accurate and maintain battery health.

But a study published in the Journal of Electrochemical Society challenges this guidance. The research found that repeatedly charging LFP batteries to full capacity can lead to faster degradation, much like what happens with nickel-based batteries. The culprit: High states of charge (SoC) increase voltage and heat within the battery, causing harmful compounds to form and deposit on the negative electrode, leading to a loss of capacity over time.

Related:7 Companies Ironing Out LFP Technology

So, what’s the big deal?

The study tested various charging ranges—from 0%-25% to 75%-100%—and under different temperature conditions. The results? Charging to 100% regularly, especially in warmer climates, can cause LFP batteries to degrade faster. For instance, in the worst-case scenario, some cells lost up to 24% of their capacity over the equivalent of 10 years of use.

While that sounds alarming, the study also notes that the actual impact on battery life might not be as significant as it seems. Even with more frequent full charges, most users will see relatively minor degradation, especially when considering the long warranties offered by manufacturers. Tesla’s LFP batteries, for example, are expected to last hundreds of thousands of miles, with a 15-year lifespan before dropping to 85% capacity.

What’s a driver to do?

So, should drivers change how they charge there EV? The study doesn’t call for a complete overhaul of your habits, but it does suggest a more balanced approach. Charging to 100% might be necessary for long road trips or during winter when range is limited. But for daily use, keeping the battery at a lower state of charge could help extend its life.

Related:Zeekr Sets a New Benchmark for EV Charging Speed with LFP Batteries

As the EV landscape evolves, research like this will continue to shape our understanding of how best to care for these batteries. For now, while LFP batteries might not be as invincible as once thought, they’re still likely to outlast the vehicle they’re powering—especially if you treat them with a little extra care.

The good folks at Interesting Engineering have a new video primer on the effects of charging LFP EV batteries; see it below: