Below are charging sessions from two Teslas, recorded in Dr.EV. Both cars charge to nearly full. The first graph is smooth. In the second, the highest cell voltage line turns into the teeth of a saw. That sawtooth is the sign to look for: it means the car is balancing its cells, and you can watch it happen live in the graph.

Battery faults usually appear while the battery is working hard: during fast charging, hard acceleration, or hard braking. This one appeared while the car was parked. Among the recent failure cases we have analyzed, it is the first that started this way.

Every Tesla driver has seen regenerative braking reduced after a full charge. The dashed line appears on the power meter, the car coasts where it would normally slow, and the friction brakes do the work for the first part of the drive.

Battery packs that are about to fail do not behave like healthy ones, and the difference is visible in ordinary charging data three months before the pack is replaced. That is the finding, and the rest of this article is how we got there and what it is worth.

Your Tesla is three months old and battery health has already dropped a few percent. Here is what the data says about where it goes from here.

Most Tesla owners notice that range estimates look worse in January than in October. The car is fine and the battery has not aged overnight. What is less obvious is how big the effect actually is, and which drivers it lands on.

Every EV owner wonders, "How much battery do I have left?" Here is how Dr.EV answers.

Below are two Tesla charging examples. Both show cell voltage behavior during charging. The difference becomes clear near the upper SOC range. One case shows balancing recovery.The other shows a condition where balancing can no longer recover the imbalance. Case 1: Balancing Recovers In the first graph, look at the circled area near high SOC. As charging progresses, the thickness of the cell voltage band becomes thinner. The spread between the highest and lowest cells gradual

Model 3 and Model Y remain the efficiency leaders, while Model X and Cybertruck show higher Wh/mile as expected.

One of our Dr.EV users recently asked us a common question: “Why is CB-R bad? And what can I actually do about it?” CB-R is a Dr.EV indicator designed to detect cell imbalance. Why cell imbalance is not good for your Tesla. When cells are imbalanced, the usable energy of the entire battery pack is limited by the weakest cell. In this case, we guide slow charging help passive cell balancing working well. Here is real graph. As SOC goes up, cell voltage differences usually get

The two charging graphs presented here are real data provided by a Korean user and a Chinese user who contacted us through the ‘Contact via Email’ feature in the Dr.EV app to inquire about their battery condition. All personal information has been removed, and only the necessary data has been used. First User (Left Graph) The user on the left performs almost all charging using DC fast charging.They frequently charge to 100 percent, and their daily charging routine also depend

This experiment is based on a user scenario in which a vehicle that is already out of warranty shows BMS a079 symptoms, and the owner tries to continue using the car as stably as possible while accepting a certain level of inconvenience. It has now been five weeks since the BMS a079 phenomenon was first detected. So far, the BMS a079 error code has still never appeared. At around week 3, the battery condition worsened slightly. So, we limited the charging level to 60% and cap

This experiment is based on a user scenario in which a vehicle that is already out of warranty shows BMS a079 symptoms, and the owner tries to keep using the vehicle as stably as possible while accepting a certain level of inconvenience. This is the third-week result since the first detection of the BMS a079 phenomenon. So far, the BMS a079 error code has not actually occurred. In last week’s middle graph, the cell voltage deviation widened up to 0.09 V. Starting this week, h

These days, because of recent Tesla issues, many people say things like “using cylindrical cells was a mistake” or “Tesla had no choice but to use them.” That might have been true long ago when prismatic and pouch cells were not widely available. But even today, choosing a cell type is far from a simple decision. In battery pack design, there is always a trade-off. Safety, energy density, manufacturing complexity, and cost are all interconnected, and the outcome depends on wh

This is the second week’s result since the first detection of the BMS a079 phenomenon last week. So far, the BMS a079 error code has not yet appeared. As shown in the left graph, even under the same charging conditions, the maximum cell deviation remains around 0.05 V, similar to last week. However, in the right graph, the maximum deviation has increased significantly to about 0.08 V. This difference is also clearly visible in the statistical data. While it’s possible to redu

Although we have analyzed numerous user datasets and real-world cases, this is the first time we have personally observed the same issue on our own vehicle. This gives us a valuable opportunity to study the problem not only from the developer’s perspective but also as an actual owner experiencing it firsthand. To share some background: the vehicle was purchased used in June of last year with about 120,000 km. It has mainly been used for development, and the annual mileage is

Previously, you could only review data from your most recent session . Now, we’ve expanded the feature so you can analyze battery and...

Until now, Dr.EV only provided the “Personalized Remaining Life Distance,” which is calculated based on your actual driving and parking...

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Usable State of Charge (SOC) Definition: Usable SOC is the battery percentage that reflects the usable energy available for driving, as...