Lithium battery repair: BMS, cells and packs

Ecobaterías repairs lithium-ion batteries in Chile: it replaces or reprograms the BMS (the electronics that measure and protect the cells), replaces weak cells and modules, rebalances the pack and replaces contactors, fuses, connectors and busbars. Every repair starts with a diagnostic and ends with a capacity test, and the battery comes back with a report of its state of health (SOH) before and after. A battery that is swollen, leaking, over-discharged or heat-damaged is not repaired: it goes to recycling.

Which batteries do we repair?

We repair lithium-ion batteries for companies and individuals. Chemistry defines the work. We handle LFP (lithium iron phosphate), NMC (nickel manganese cobalt), NCA (nickel cobalt aluminum), LCO (lithium cobalt oxide) and LTO (lithium titanate).

We do not repair nickel-metal hydride (NiMH) batteries, used in several generations of the Toyota Prius, or lead-acid batteries. Their recycling is quoted separately.

Swipe to see the whole table

Reference standards: EN 50604-1:2016 and UL 2271 for light electric vehicle batteries; ISO 12405-4:2018 for testing vehicle packs; IEC 62619:2022 for industrial lithium batteries, such as telecom, UPS, storage and forklift batteries. We use them as references for our method. They are not certifications we hold.

Sources: EM3ev (cells in series in e-bike packs) · EU battery ecodesign study, 2019 · IEC 62619:2022 · Toyota Prius, Wikipedia

What can be fixed and what cannot?

A pack failure usually sits in one part, not in every cell. According to Autocraft EV Solutions, across 559 commercial electric car pack repairs carried out in 2024, 92% of modules were still fit for automotive use and replacing 1.1 modules per pack on average was enough.

Swipe to see the whole table

Three terms from the table: a contactor is the switch that connects and cuts the pack’s high voltage; the pre-charge circuit limits current at the moment the pack is connected; busbars are the metal bars that join cells and modules.

Sources: Autocraft EV Solutions, 2025 · ETH Zürich and UL 1974 (damaged batteries) · Regulation (EU) 2023/1542, Annex V (over-discharge)

Diagnostic first

We do not quote a repair without measuring the battery. The lithium battery diagnostic tells what failed, how much capacity is left and whether repair makes sense. Its main result is the state of health (SOH): how the battery performs today compared with when it was new, expressed as a percentage of its original capacity. More terms in the glossary.

Swipe to see the whole table

The letter C expresses current relative to capacity: 1C discharges the full battery in one hour and 0.2C in five. A resistance test takes seconds; a capacity test takes hours. In our laboratory, testing a pack takes between 30 minutes and 6 hours.

Sources: UL 1974:2023 · UN R100 · Battery Design · Zhang et al., 2025 · EU ecodesign study, 2019 · Ecobaterías test protocol

How we repair: the six-step protocol

1. Intake and quarantineRegistration with a unique code, visual inspection and thermography. Any battery that is swollen, dented, leaking or warm at rest is isolated and does not enter repair.
2. DiagnosticBMS readout, insulation, voltage per cell or group, internal resistance and a capacity test. The result is the fault found and the initial SOH.
3. Quote and decisionWe send you the fault, what we propose to replace, the price and the lead time. If repair does not make sense, we propose refurbishment, second life or recycling.
4. RepairWith the pack disconnected and using insulated tools, we replace the BMS or its firmware, the weak cells or modules with others matched in voltage, internal resistance and capacity, and any damaged contactors, fuses, pre-charge parts, connectors or busbars. We finish with balancing.
5. Exit testCapacity, internal resistance, insulation and a check of the BMS protections against overcharge, by voltage and by current, and against overtemperature, the controls IEC 62619 requires from the BMS of industrial batteries.
6. Handover and reportThe battery comes back with the repair report: fault found, parts replaced and SOH before and after. Removed cells or modules go to recycling with a certificate.

The sequence takes UL 1974:2023 as a reference: gather information, inspect, test and grade.

What do you receive after the repair?

• Diagnostic report with the fault, the measurements and the route we recommend: repair, refurbish, second life or recycle.
• Repair report with the parts, cells or modules replaced, the SOH before and after, and the exit internal resistance and insulation.
• Intake and traceability certificate for the removed cells and modules we send to recycling, useful for your company’s reporting under Chile’s Extended Producer Responsibility law (Ley REP, Law No. 20,920).
• Warranty per contract: its scope is set in writing in the quote. If you are a consumer, Chile’s consumer protection law (Law No. 19,496) also applies.

A note on transport: if the repair changes the type or number of cells, the BMS (hardware or software) or how the cells are connected, the battery may count as a new type under subsection 38.3 of the UN Manual of Tests and Criteria and need new tests to ship as dangerous goods. IATA’s 2026 guidance expressly mentions repair with non-original parts or parts of a different specification. When it applies, we say so in the report.

Sources: UN Manual of Tests and Criteria, 38.3 · IATA, 2026 · Law 19,496, BCN

How long does it take and how much does it cost?

Price and lead time are confirmed in the quote, after the diagnostic. We reply within 48 business hours. These variables set them:

Swipe to see the whole table

International reference: in the United States, replacing the full battery of an electric car out of warranty costs between US$5,000 and US$16,000, and a replacement BMW i3 module about US$3,500, according to Recurrent. When the fault is in one or two modules, replacing only those modules avoids replacing the pack.

Source: Recurrent, EV battery replacement costs · updated 2024-12-03

Safety limits: what we do not repair

Some batteries are not opened for repair, because the risk is no longer about performance but about fire. The biggest one is thermal runaway: a chain reaction in which the cell heats itself until it releases gas, fire or both.

We do not repair batteries in these conditions:

• Swollen or deformed, leaking, smelling, with melted areas or heating up while switched off. ETH Zürich classifies them as damaged batteries.
• With burn marks or a previous thermal event. UL 1974 rejects them at intake.
• Over-discharged or at 0 V. According to Regulation (EU) 2023/1542, over-discharge reverses polarity and oxidizes the anode’s copper current collector, and even a minor over-discharge can grow dendrites and end in an internal short circuit. We do not recover them for reuse: they go to recycling.
• With mechanical damage: dents, punctures or a crushed case or module.

A battery that is swollen, leaking, dented or heat-damaged ships as “damaged or defective” (UN special provision 376): in its own inner packaging, surrounded by non-combustible, non-conductive thermal insulation (packing instruction P908, packing group II), or in P911 packaging if it could react dangerously during transport. Damaged batteries that could produce dangerous heat, fire or a short circuit are forbidden on aircraft. We coordinate pickup with licensed hazardous-waste transport.

If a battery heats up, smokes or swells

• Do not charge it or open it.
• Move it at least 15 meters (50 feet) away from buildings and combustible materials. A damaged battery can reignite hours or days later: NTSB documented one case five days later.
• If it burns or smokes, call the fire department (Bomberos, 132 in Chile) and cool it with plenty of water. An ABC extinguisher does not stop thermal runaway: NTSB recorded electric car fires that used more than 20,000 gallons (about 75,000 liters) of water.
• If it is cold but swollen, wear gloves, tape the terminals and store it alone in a plastic container with sand or vermiculite, in a cool, dry place, away from metal and other batteries.
• Do not throw it in the trash or a regular bin.

Sources: ETH Zürich · UL 1974 · RID 2025 (SP 376, P908, P911) · IATA, 2026 · NTSB, SR-20/01 · Cirba Solutions and US EPA (storing damaged batteries)

When is repair not worth it?

Repair means fixing a specific fault and returning the battery to the same use. Refurbishment means taking the pack apart, testing every cell and replacing the weak ones. When the problem affects the whole pack, another route pays off better:

Swipe to see the whole table

Thresholds from the Ecobaterías test protocol: SOH ≥ 90% direct reuse · ≥ 80% refurbishment · 65–80% second life · < 65% recycling. These are in-house thresholds, not a standard.

In the European Union, a refurbished pack is called “remanufactured” only if all its cells were assessed, it recovers at least 90% of its original rated capacity and the SOH of its cells differs by no more than 3% (Regulation (EU) 2023/1542, art. 3(32)). UL 1974 treats “remanufactured”, “reconditioned” and “rebuilt” as equivalent.

Only have a few household batteries that no longer work? See where to recycle lithium batteries in Chile.

Regulatory framework

• Law No. 20,920. It defines preparation for reuse as checking, cleaning or repairing a discarded product so it can be used again without further processing (art. 3 No. 18). If the battery was already waste, repairing it is a form of valorization (art. 3 No. 30).
• Draft battery decree (Res. Ex. 821/2026). It proposes targets for lithium-ion batteries of 5 kg or more: no target in the first two years, 15% in the third and 50% from the tenth, with at least 30% of the target met through preparation for reuse. It is a draft, not a rule in force: its public consultation closed on April 9, 2026, and the Ministry of the Environment’s deadline to propose the decree is January 29, 2027.
• Regulation (EU) 2023/1542. It lists repairers among independent operators (art. 3(23)); since August 18, 2024, the BMS of light means of transport, electric vehicle and storage batteries must give read access to its state-of-health data (art. 14); and from February 18, 2027, the cells of e-bike and e-scooter batteries must be replaceable by an independent professional (art. 11). It does not apply in Chile; we cite it as a reference.
• IEC 62619:2022. Safety of industrial lithium batteries; it requires the BMS to control overcharge and overtemperature. A reference standard, not a certification we hold.
• UN 38.3 and transport. Eight UN tests for shipping lithium batteries: altitude, thermal, vibration, shock, external short circuit, impact, overcharge and forced discharge. An intact battery going to recycling travels under special provision 377 with P909 packaging; a damaged one under 376. What to require from an authorized waste manager.

Sources: Law 20,920, BCN · Res. Ex. 821/2026 and Res. Ex. 4,225/2026, Ministry of the Environment · Regulation (EU) 2023/1542 · IEC 62619:2022 · UN subsection 38.3 · RID 2025

Frequently asked questions

Can a lithium battery be repaired?

Yes, when the fault is in the BMS, a fuse, contactor or connector, or a weak cell or module. It is not repaired if it has swollen, leaking, over-discharged or heat-damaged cells: that battery goes to recycling. According to Autocraft EV Solutions, across 559 electric car pack repairs carried out in 2024, 92% of modules were still fit. That is why we always start with a diagnostic.

Can a swollen lithium battery be repaired?

No. A cell that is swollen, leaking, has melted areas or heats up while switched off is considered damaged and is not opened for repair. Store it alone, away from combustible materials, and ship it as a damaged battery (UN special provision 376, P908 packaging). We coordinate pickup with licensed hazardous-waste transport and send it to recycling.

Why won’t my lithium battery charge?

The charger may have failed, a connector may be loose or a fuse blown, or the BMS may be cutting off charging because it detects overvoltage, overtemperature or an unbalanced cell group. If the cells were over-discharged or dropped to 0 V, we do not recover them: over-discharge damages the copper current collector and can cause an internal short circuit. The diagnostic separates these causes by measuring each cell group and reading the BMS.

Can the BMS of a lithium battery be repaired?

Yes. Depending on the fault, the BMS is reset or reprogrammed, or the board is replaced. Afterwards we check that it cuts off charging on overvoltage, excess current and overtemperature, the controls IEC 62619 requires from the BMS of industrial batteries. In the European Union, since August 2024 the BMS of light means of transport, electric vehicle and storage batteries must give read access to its state-of-health data (Regulation 2023/1542, art. 14).

Where can I get an e-bike battery repaired?

At Ecobaterías we repair lithium-ion packs from e-bikes, scooters and electric motorcycles: BMS, charging port, weak cell groups and balancing. A 36 V pack has 10 cell groups in series; a 48 V pack, 13; and a 52 V pack, 14. We take in batteries in Santiago and Viña del Mar and coordinate drop-off or pickup anywhere in Chile. Before quoting, we measure every cell group.

Can a cordless drill battery be repaired?

Yes, if the fault is in the protection board, a connection or some of the cells. An 18 V tool battery holds 5 lithium-ion cells in series. We replace weak cells with new cells matched in voltage and internal resistance, and test the capacity before returning it. If the case is deformed or a cell is swollen, it is not repaired and goes to recycling.

Can a hybrid battery be repaired?

Only if it is lithium-ion. Several generations of the Toyota Prius, for example, use nickel-metal hydride (NiMH) batteries, and we do not repair those. If your hybrid has a lithium-ion battery, the diagnostic shows whether replacing a module, a sensor or a contactor is enough. The chemistry is on the pack label or in the vehicle manual.

How long does a lithium battery last in an e-bike or electric motorcycle?

There is no single figure: it depends on the chemistry, the number of charge cycles, heat and how the battery is charged and stored. What can be measured is how much life is left. A capacity test gives the state of health (SOH) as a percentage of the original capacity, and that figure decides whether to repair, refurbish or recycle it.

How can I tell if a lithium battery is still good?

With measurements, not by eye. First, rule out visible damage: swelling, leaks, odor or heat while switched off. Then measure the resting voltage of each cell group, the internal resistance and the real capacity over a full charge and discharge cycle. Measured capacity against the original is the state of health (SOH): in our protocol, at 90% or more a battery is reused as is, and at 80% or more it can be refurbished for the same use.

How much does lithium battery repair cost?

It depends on the format, chemistry, fault and spare parts, so the price is confirmed in the quote, after the diagnostic. We reply within 48 business hours. For reference, in the United States replacing the full battery of an electric car out of warranty costs between US$5,000 and US$16,000, according to Recurrent; when the fault is in one or two modules, replacing only those modules avoids replacing the whole pack.

More answers on recycling, pickup and Chile’s EPR law in the FAQ.

Sources

Updated September 26, 2026 · Reviewed by the Ecobaterías technical team