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Four Best Practices to Keep Your LFP Battery Healthy for Years

A recent study from Jeff Dahn's lab at Dalhousie University shows that cycling LFP batteries near the top of charge (75–100%) causes the most degradation, while lower operating windows preserve capacity. Here are four practical rules — backed by science — for getting the most life out of your LFP-equipped EV.

15 Apr 2026 charging, LFP, battery, guide, EV maintenance

Video thumbnail — Engineering Explained

What you need to know first

Lithium iron phosphate (LFP) batteries are rapidly replacing NMC (nickel manganese cobalt) in standard-range EVs from Tesla, Ford, BYD and others. LFP is expected to overtake NMC globally by 2028. The catch: best practices for LFP are almost the opposite of what NMC owners follow.

The advice below draws on a peer-reviewed study from Jeff Dahn's lab at Dalhousie University, published in the Journal of the Electrochemical Society. The researchers cycled LFP/graphite cells across five state-of-charge (SOC) windows — 0–25%, 0–60%, 0–80%, 0–100% and 75–100% — for 2,500 hours each at elevated temperatures. Their headline finding: cycling near the top of charge is the single biggest factor in capacity loss.

Steps to follow

1. Charge to 100% at least once per month

LFP batteries have a very flat voltage curve in the middle SOC range, which makes it nearly impossible for the battery management system (BMS) to estimate remaining charge accurately from voltage alone. Charging to 100% triggers a voltage spike that lets the BMS recalibrate. Tesla recommends doing this at least once per week; Ford says once per month. Either way, this is non-negotiable for accurate range readings.

2. Operate at a lower SOC range day-to-day

The Dahn study found that cells cycled from 0–25% degraded the least, followed by 0–60%, then 0–100%. The worst performer was the 75–100% window. The mechanism: at higher SOC the battery sits at higher voltage, which accelerates harmful side reactions. Iron dissolves from the positive electrode, migrates to the graphite negative electrode, and consumes lithium inventory — permanently reducing capacity.

In practice, this means you do not need to top up every night. Let the battery drain down before plugging in, and avoid spending most of your time in the 75–100% band.

3. Store at roughly 50% for extended periods

If you are leaving the car parked for weeks or months — a holiday, for instance — set the charge limit to around 50%. A lower voltage during storage means slower side reactions and less degradation. Both Tesla and Ford give this same recommendation in their owner's manuals.

4. Only plug in when you actually need to

This is the opposite of NMC advice, where frequent small top-ups are ideal. For LFP, repeatedly cycling in a narrow band at the top of charge is the worst-case scenario from the Dahn study. Letting the battery drain further between charges means each cycle covers a broader, lower SOC window — exactly what the data says is better for longevity. Tesla's own in-car charging screen hints at this: "charge fully once per week" implies you should let it drain between sessions.

Tips and caveats

Never let it hit 0%. Deep discharge can cause permanent cell damage. The study's 0–25% window does not mean you should routinely drive to zero — manufacturers build in a buffer, but the margin is thin.
Temperature matters. The study ran at 40°C and 55°C to accelerate degradation. In cooler climates the effects are slower, but the ranking of SOC windows stays the same.
If you cannot charge at home, LFP may suit you better. You can charge to 100% at a public charger without guilt, then let it drain down over the week — exactly the pattern LFP prefers.
Chemistry varies. Different LFP formulations and electrolytes can shift the exact numbers. The principles hold, but your car's specific cells may behave slightly differently.

Sources