Model 3/Y: HV battery module-level repair — who can do it in Belarus and what it costs

This article is about repair: who, where and for how much replaces modules, fits a refurb pack, performs recalibration. For symptoms, diagnostics and the 82 kWh imbalance cases see the article m3-my-82kwh-panasonic-imbalance — not duplicated here.

Summary

The Model 3/Y HV battery consists of 4 modules (long-range/AWD), each with ≈ 600–800 21700 cells in parallel/series. When one module degrades — the pack imbalances, BMS limits power and/or shows an error. Good news: the module can be replaced separately, without buying the whole pack for $12–16k. Bad news — there are very few such service shops in Belarus, and you need to understand the criteria "module vs refurb-pack vs new pack".

Cases and solutions

Scenario A: one weak module, the rest healthy.

• Symptom: "after winter caught an imbalance", BMS_A064 / A079 / A066, capacity 15–25% below normal for the mileage, severe SOC drift after CCS charging.
• Solution: module replacement with a donor of similar SoH + full balancing (12–24 hours on slow charging) + BMS relearning.
• Service life of such a repaired battery: 3–5 years if the donor is matched by year and mileage. Longer — if lucky.

Scenario B: 2–3 modules "gone", pack busbars corroded.

• Solution: refurb pack (rebuilt from 2–3 donor packs, tested, with reflashed BMS).
• In Belarus available through service shops as "refurbished HV battery" or assembled by a tech for the specific car.

Scenario C: hole in the case, water inside, busbar oxidation.

• Treated with removal → disassembly → busbar and drain replacement → re-drying → reassembly. Sometimes + replacement of 1–2 modules.
• This is the most expensive and unpredictable repair.

Scenario D: "everything bad" (5+ modules dead).

• Cheaper to take a refurb pack / new OEM or sell the car "for parts".

Who does this in Belarus (as of April 2026)

Service names verbatim from the site registry — we don't use others.

• ЭлектроЭра (Minsk, Radialnaya 11) — main player on battery work, in chat most often mentioned as "they do both modules and full packs".
• TESLAMINSK.BY (Zemledelcheskaya 52) — 10 years on EVs, diagnostics and battery work. Contact: Fyodor @Iamfbo.
• Теслашоп (Kolodishchi) — diagnostics, module replacement when a donor is available.
• ТеслаЛаб (Petrusya Brovki 30) — diagnostics, retrofits, optionally pack-level work.

What it costs in Belarus

Parts:

• One 21700 module (from a donor, M3/Y) — ≈ $400–800, depending on SoH, year and how hard it was driven (source: Western wrecking yards + chat). On LR/AWD pack 4 modules; on SR — 2.
• Refurb pack M3/Y 75 kWh (LG / Panasonic 79–82) — ≈ $4 500–7 500.
• New OEM Tesla pack — ≈ $12 000–16 500 + import and logistics (source: https://www.findmyelectric.com/blog/tesla-model-3-battery-replacement-cost/). In Belarus practically nobody buys it — uneconomical.
• Replacement with LG 79 kWh (for problematic Panasonic 82) — discussed as an alternative; pack price comparable to refurb above.

Labor (Minsk, $50/h):

• Pack removal and installation: 6–10 hours = $300–500.
• Pack disassembly, 1 module replacement, reassembly: 8–14 hours = $400–700.
• Replacement of 2–3 modules + balancing + BMS recalibration: 16–24 hours = $800–1200.

Total by scenario:

• A (1 module): ≈ $700–1500 (part $400–800 + labor $300–700).
• B (refurb pack): ≈ $5 000–8 200 (part $4500–7500 + labor $400–700).
• C (water, case repair): ≈ $1 800–4 500 (depends on scope).
• D (new OEM): ≈ $12 500–17 000 (including logistics + labor).

DIY notes (for understanding, not for replication)

• HV battery ≠ 12V battery. Inside is 350–400 V DC, without service-disconnect and without HVIL understanding — fatal outcome.
• Before battery repair, make a full cell log via ScanMyTesla / Service Mode → Battery → Cell Voltages. This shows which modules are actually weak. Without this, repair = guessing.
• Module replacement must be accompanied by extended balancing at low SOC (see procedure in the article m3-my-82kwh-panasonic-imbalance).
• After replacement: BMS recalibration (Service Mode → Battery Test) for 12–24 hours, so the new module "syncs" by SOC with the rest.
• When buying a refurb pack, ask the tech for a cell report (at least voltages/balance at 90% SOC) — that's a must-have. Without a report — lottery.
• Don't buy a "wrecking-yard battery" without a visual inspection of the case. 30% of those in Belarus are post-impact / post-flood, and within a year a hole in the case or busbar corrosion will appear.

Links

• Gruber Motors — Main Battery Pack Repair (model approach to repair): https://grubermotors.com/services/model-s-main-battery-pack-repair/
• Gruber Motors — labor pricing example: https://grubermotors.com/services/model-s-main-battery-pack-repair-pricing/
• Gruber Motors — Main Battery Modules (modules for sale): https://grubermotors.com/product/main-battery-modules/
• FindMyElectric — Tesla Model 3 Battery Replacement Cost (full pricing guide): https://www.findmyelectric.com/blog/tesla-model-3-battery-replacement-cost/
• TMC: "Firsthand experience with out-of-warranty battery replacement cost": https://teslamotorsclub.com/tmc/threads/firsthand-experience-with-out-of-warranty-battery-replacement-cost.327730/
• InsideEVs — "Gruber Motors Details New Tesla Model S Battery Pack Repair Process" (logic also applies to M3/Y): https://insideevs.com/news/451095/tesla-model-s-battery-pack-repair-gruber-motors/
• YouTube: "Model 3 Battery 2170 Cell extraction — BMS_A064 BMS_A079 BMS_A066" (diagnostics and module extraction): https://www.youtube.com/watch?v=1-TF5MSDJ6Q
• YouTube: "DIY Tesla Model Y and 3 main HV battery swap replacement": https://www.youtube.com/watch?v=zv6HUlbQOxc

Community experience

Analysis of ≈ 400,000 messages from the TESLA owner's group BELARUS chat — battery topics are top-3 by discussion volume.

What's said about M3/Y pack repair:

1. Pack structure: Zverski, #92459 — "Module. Battery of 16 modules. Multiply" (for S/X 85 kWh). For M3/Y — 4 modules (LR/AWD) or 2 (SR).
2. Main diagnosis — Panasonic 82 imbalance: Алексей, #76903: "imbalance only on Panasonic 82 I've seen". Dzianis Balyka, #103046: "panasonic vs lg — on LG so far fewer imbalance cases known to this chat".
3. Repair vs full pack replacement logic: firago, #134550 — "there were a number of cases (very large) that in the mileage range from 50,000 to 90,000 km a cell in a module fails. This can be repaired, but if you react quickly, even without module replacement. More often people at this moment restore the car after body damage or it's just sitting, and during this time the sector discharges to a hard 0, which is no longer repairable, requires full module replacement".
4. Key case with a hole in the case and repair estimate: Zverski, #142064 — detailed labor cost breakdown: "15 of 16 modules were sold and… 2-3 with partial corrosion, which is probably even recoverable… 400 to remove-install, well 400 to open-close, well 1000 for one dead module, well 400 each for repairing 3 modules and $100 to a drunk welder to weld the hole in the case". — gives a real price range for an S/X case; for M3/Y the scale is similar, scope smaller.
5. Diagnostics recommendation: Pasha n1claus, #137057 — "would normal service diagnostics show this? You'd see cell imbalance on a computer before the car throws an error in theory?". — Yes: ScanMyTesla/Service Mode sees cell drift months before a hard error.
6. Important factor — sitting kills batteries: firago, #134550: "lithium really doesn't like to be stored and just wait… the car must drive, charge and discharge and sit less, especially in winter when it's cold. The HV batteries that live best are those with annual mileage from 25,000 km".

Who reported the issue: Сергей, Shark Dark, Vitali K, AleXXXiz, Pasha n1claus, mouSe, anonymous.

Who found the fix: Pasha n1claus, Zverski, SΞDΞK, Alex Bor, Stinger, firago, Денис, Адриан.

Discussion in Telegram: #76903, #92459, #103046, #134550, #137057, #142064, #143391.

Related article: for symptoms, diagnostics and preventive balancing specifically for the Panasonic 82 case — see m3-my-82kwh-panasonic-imbalance.