Tesla battery health: tests, capacity and estimates

There are several ways to discuss a Tesla’s battery health: Tesla’s own evaluation, an optional vehicle test and estimates built from reported battery data. Knowing which one you are looking at is essential before comparing percentages.

Odomojo uses the term estimated capacity retention for its comparison of a received nominal full-pack energy reading with a suggested or customer-supplied original reference. Its accuracy depends on both inputs, including whether the reference fits the installed battery.

Start with Tesla’s own battery-health information

Tesla’s European Model 3 manual describes an evaluation under Controls → Service → Battery Health. It also describes an optional Battery Health Test, where supported, that returns energy retention relative to new. The test can require up to 24 hours connected to AC charging, and Tesla recommends it when there is a concern about energy retention. Availability varies; consult the manual for your vehicle.

An existing test result and its date can be useful context when discussing another estimate. Odomojo’s capacity display does not retrieve or reproduce that test result.

What software 2026.32 adds

Tesla’s official telemetry schema lists NominalFullPackEnergyKwh, field 263, in the group first available with vehicle firmware 2026.32 and telemetry client 1.3.0. This provides a nominal full-pack energy signal in kWh. The versioned Tesla schema is the source for that requirement.

This is a capacity input for a comparison, rather than a health percentage with an original reference already attached. We have not established that its treatment of buffers and software limits makes it interchangeable with published usable capacity.

Vehicle software is one requirement. The receiving service must support and request the field, collection must be permitted, and the car must actually send a valid reading. A version number or a connected Tesla account does not prove that capacity data has arrived.

The August update article explains the source change and Odomojo’s first receipt check.

How Odomojo presents the information

Where capacity collection is enabled and valid data has arrived, the Battery section separates:

• Nominal full-pack capacity: the reported kWh value and its own observation time.
• Original-capacity reference: the catalogue suggestion or the value saved by the customer, with its basis visible.
• Estimated battery health: the approximate capacity-retention ratio when both inputs are available.
• Reported capacity history: retained kWh observations, which can be inspected even without an original reference.

The calculation is current nominal full-pack kWh divided by original nominal reference kWh, multiplied by 100. Odomojo shows an approximate whole percentage. This is not a measured error bound or a claim that the reference is accurate to one percentage point.

If the reported capacity exceeds the reference, Odomojo asks for the baseline to be checked instead of silently reporting 100%. Missing or unusable inputs leave the estimate unavailable.

Can the VIN identify the original capacity?

Odomojo combines saved vehicle details, including relevant VIN attributes and trim information, with a reviewed catalogue. A unique match can suggest an original capacity. Several matching variants remain a choice to review; unsupported or conflicting details remain unknown.

This is a deterministic suggestion from the evidence available. It does not confirm the physical pack, decode every production change or discover an undocumented replacement. The number in a trim badge is not automatically a kWh measurement.

Customers can save a different original-capacity value and later restore the suggestion. Saving a value changes the denominator of the estimate, so the saved value and its provenance stay visible. A replacement battery is a reason to review that reference.

How to read a capacity history

Use the observation times and look for comparable readings. Odomojo’s history displays reported kWh within retained coverage; it does not reconstruct the car’s lifetime capacity or assume a smooth path through missing data.

A short series cannot establish a long-term degradation rate. We are still validating the relationship between this Tesla signal, appropriate original references and other health evidence. No fleet-wide accuracy result follows from confirming receipt on one vehicle.

Availability in Odomojo

Since 19 October 2026, capacity collection is available to all eligible connected Teslas, including future connections and vehicles on a tracking trial. Odomojo checks reported firmware periodically and requests capacity automatically when software 2026.32 or later and the existing collection requirements are satisfied. No separate support approval is needed.

Vehicle-key setup, manufacturer permission, tracking hours, pauses and trial or subscription access still apply. Odomojo does not wake a vehicle or resume paused tracking to collect capacity. A compatible version and an accepted configuration are not proof of receipt: the estimate stays unavailable until a valid reading and a suitable original reference exist.

Check Tesla compatibility and follow the connection guide. Contact Odomojo if you need help with missing readings. For the terminology and comparison checklist, see EV battery state of health.