LFP Battery Pack:How Much Should You Charge?
Many new energy vehicle (NEV) owners have wondered: “Should I always charge my battery to 100%?” It’s a topic with lots of debate—especially when it comes to lithium iron phosphate (LFP) battery packs. What many don’t realize is that LFP batteries do require regular 100% charges, unlike other lithium-ion batteries.
📊 LFP Batteries Dominate the Market
As of 2024, LFP battery packs account for over 560 GWh in shipments, representing around 72% of total power battery shipments. In other words, the majority of electric vehicles (EVs) on the road today are equipped with lithium iron phosphate battery packs.
✅ The Bottom Line: Yes, You Should Charge to 100%
For electric vehicles using LiFePO₄ (lithium iron phosphate) battery packs, it’s crucial to charge fully from time to time — not to maximize range, but to improve state-of-charge (SOC) detection accuracy and ensure the battery management system (BMS) knows exactly how much power is left.
📉 The "Platform Period" Phenomenon
LFP batteries have a wide voltage plateau, where voltage doesn’t fluctuate much over a large state-of-charge (SOC) range. For instance, between 28% to 75% charge, the voltage fluctuation is typically less than 2%. This stable voltage range is known in the industry as the “platform period.”
The downside? Voltage-based SOC estimation becomes highly inaccurate within this period, forcing the battery management system (BMS) to rely on algorithmic estimation rather than actual measurements.
Imagine driving your EV for a week, regularly charging and discharging within this 20%-80% range. Everything seems fine—until you realize your range estimates are off. Not a big deal in town, but it can be a problem on a long road trip.
🔧 Two Ways to Fix SOC Inaccuracy
There are two key methods to recalibrate your LFP battery and restore accurate range readings:
Discharge Below the Platform Period
Let the battery drop below 10% and leave the car parked overnight. The system can then get a reliable voltage reading, recalibrate the SOC algorithm, and improve accuracy for the next cycle.Fully Charge Once a Week
Brands like Tesla, BYD, and Geely recommend charging your LFP battery to 100% about once a week. This allows the system to exit the “platform period” and perform a reset.
🔄 Escape the Platform Period—One Way or Another
In short: keep your battery out of the platform zone by either going low or going high. If you ignore this advice, it won’t damage your battery, but expect inaccurate range readings.
⚡ A Fun Fact About Public Chargers
Did you know? Many public fast chargers don’t actually charge to 100%. Most are set to stop at around 98% SOC, meaning your battery never truly gets full. That’s why home charging is critical for proper battery calibration.
🏡 Home Charging = Better Calibration
A home AC charger is your best friend when owning an LFP-powered EV. Unlike fast chargers, it slowly and fully recharges your battery, allowing the system to recalibrate while the vehicle sits overnight.
🔋 What About Other Lithium-Ion Batteries?
Other lithium batteries don’t have this voltage plateau, so they don’t require weekly full charges. However, periodic full charging is still recommended for accurate SOC calibration over the long run.
⚡ Ideal Charging Strategy
The best charging method combines:
High current in early stages
Low current near full charge
Slow, steady “topping off” toward 100%
This is where a 220V/32A AC home charger shines. Theoretically, it can deliver 6 kWh per hour, meaning up to 60 kWh overnight, more than enough to fully charge most EV batteries—especially those using LFP chemistry.
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