The test: no history, just the car’s own diagnostics
Matt’s daughter and son-in-law bought the used Model 3 at around 76,000 miles (122,000 km). They knew almost nothing about how the previous owner charged it—DC fast chargers or AC wallbox, how often it sat at 100%, or whether it was regularly discharged to low states of charge. For a used EV buyer, that’s normally a risk factor, not a deal-breaker.
As InsideEVs reported, the Tesla built-in battery test requires the car to be plugged in, discharge its battery, and then charge back to full while measuring energy. The car drew 62.4 kWh from the charger. After allowing for the usual 10% charging losses, that is about 56.2 kWh stored. Since Tesla doesn’t publish exact capacities, the pack’s gross capacity when new is estimated at around 60.5 kWh. That gives 92.9%.
This is not a laboratory measurement. The car does not expose a standalone “battery capacity” value in the normal interface, so any health figure derived from this test is an estimate based on how much energy the onboard charger takes from the grid and how much is lost as heat during the full discharge-charge cycle. The result is useful, but it should be read as a consistent diagnostic figure rather than a certified laboratory number.
Gross vs usable: why 92% is the number to quote
There is a trap here. If you compare the stored 56.2 kWh with the original usable capacity of the early LFP pack—often quoted at 57.0 to 57.5 kWh—you get 97.7 to 98.6% remaining. That sounds better than 92%, but it is not a reliable shortcut because the car’s starting state of charge, actual conversion losses, and energy used by the thermal system were not measured independently. Tesla’s own diagnostic output gives the energy drawn from the wall, not a direct cell-level measurement; the 60.5 kWh gross estimate is the reference point that makes the 92.9% figure credible.
For an owner or a used-car buyer, the more conservative number is the one to keep in mind. Losing roughly 7.1% of estimated gross capacity over 125,000 km is not alarming, but it is real. That translates to a little less motorway range than the car showed when new—perhaps enough to notice on a long winter trip, but not enough to make the car unusable for normal European travel.
What this means for an LFP battery
LFP chemistry is generally comfortable with high states of charge, and Tesla explicitly tells owners of LFP cars to charge to 100% at least once a week for calibration. That makes an unknown charging history less frightening than it would be on an older nickel-manganese-cobalt pack, where being held at 100% is often treated as a long-term stress factor.
The 92.9% result after 77,726 miles also leaves plenty of margin above the common EV battery warranty threshold of 70% retention. In practice, that means the vehicle is still far from the point where the manufacturer would consider the pack defective under a typical battery warranty.
European angle: the same car, the same likely result
European readers likely know this car well. The Shanghai-built Model 3 rear-wheel drive with the LFP pack has been one of the most common entry-level electric sedans in Germany, France, the Netherlands and other EU markets since 2021. A high-mileage used example in Europe will very often be the same specification as the car tested here, even though the mileage is recorded in kilometres rather than miles.
For buyers looking at ex-fleet or private used Model 3s, this data point is a useful sanity check. A 2022 car with 125,000 km on the odometer should not automatically be rejected because of the battery. If the pack still holds around 92% of its original gross capacity, the real-world penalty is a modest reduction in range, not a collapsing asset.
Practical takeaway
The reassuring conclusion is that even with an unknown charging past and high mileage, this LFP pack has retained 92% state of health. Used EV buyers in Europe should still try to see the car’s own battery health readout or perform a full discharge-charge test before buying, but they can stop treating 100,000-plus kilometres as a magical danger zone for LFP cars. Battery wear is real, but it is slow—and this test shows what a normal, well-used Tesla Model 3 LFP can look like after roughly four years.
Source: https://insideevs.com/news/804780/tesla-model-3-lfp-degradation/
