Battery Test — battery calibration via Service Mode

Description

Battery Test is a BMS diagnostic and calibration procedure: it runs a full discharge-charge cycle and refreshes the capacity/range estimate, showing the battery's real state. Useful after buying a used Tesla and when you suspect battery problems.

Understand what the test is NOT. It's not a cure for imbalance: the balancer in the pack is there from the factory and runs constantly on its own (during sleep, on slow charging). If imbalance codes (BMS_a066/a064/a079) persist, the always-on balancing is no longer coping — the cells have degraded, and the test won't "heal" them: at best it temporarily evens out the readings. The real fix is a module/pack replacement.

How to run Battery Test

1. Only on a slow charger (Type 2 / Wall Charger), NOT on CCS.
2. You need a charger that doesn't drop the session on pause — in Minsk, NB and EVICA stations work.
3. Discharge to 2-3%, start the test in Service Mode, wait 12-18 hours.
4. The charger must deliver at least 5 kW.
5. Once every six months is Tesla's limit (the test cannot be run more often), not a recommendation. Run it rarely and only if you suspect a problem: each test is a full discharge/charge cycle for the battery.

Community experience TESLA Belarus

From the TESLA owner's group BELARUS chat — analysis of 400 000 messages.

Who reported the issue: Vitali K, Сергей

Who found the fix: Stinger, SΞDΞK, Dzianis Balyka, AV, Pasha n1claus

Discussion in Telegram: #176501, #259300

Links

• Calibrating the BMS — Tessie Help Center: https://help.tessie.com/article/78-calibrating-the-battery-management-system
• Tesla BMS Calibration (EV Inventory): https://ev-inventory.com/guide/tesla-bms-calibration.php
• Tesla's Battery Health Test (Not a Tesla App): https://www.notateslaapp.com/news/2049/teslas-battery-health-test-see-your-battery-health-in-app-or-in-service-mode