Degradation

Your Tesla Battery Health Test Says 78%. OBD Says 73%. Which Is Right?

Here’s a question that comes up constantly in Tesla owner forums, almost word for word:

“Coming up on 200k km. Tesla’s battery health test says 78%, but the OBD data works out to about 73%. Where does the difference come from — and which one is right?”

It’s a good question, and the answer matters, because a five-point gap sounds like the difference between a healthy pack and one heading for trouble. So people panic. They shouldn’t — and the reason why is a nice illustration of the difference between a number and a measurement.

What's Normal Tesla Battery Degradation? Data from 100,000+ Vehicles

“My Tesla lost 15 miles of range in the first year — is that normal?”

This is probably the most common question in Tesla forums. The short answer: yes, probably. But let’s look at the data.

The figures in this article are drawn from published large-fleet degradation datasets — chiefly Geotab’s EV battery degradation study, Recurrent’s Tesla range reports, and Tesla’s own Impact Report — cross-referenced with owner-reported numbers on Tesla Motors Club and Reddit. They’re population averages: your individual pack depends on climate, charging habits, and configuration.