Lesson 1Battery repair process workflow: isolation, safe disassembly, cell verification, balancing, reassembly, and test cycleFollow a solid, safe flow for battery fixes. Practice cut-off, opening packs, checking welds and covers, swapping cells, balancing, sealing up, and test runs before handing back scooters.
Isolation, PPE, and workbench preparationOpening packs without causing new damageCell replacement, welding, and insulationFinal balancing, sealing, and test ridesLesson 2Cell-level diagnostics: IR measurement, capacity estimation using simple timed load test, and spotting cell imbalancesGo deep into cell testing. Measure inner resistance, guess capacity with timed load, spot uneven parallel groups, and pick which cells to save or bin for safety or cost.
Using ESR meters and four-wire techniquesTimed discharge tests for capacity estimatesFinding weak cells within parallel groupsCriteria for rejecting marginal cellsLesson 3BMS and firmware checks: extracting BMS logs/telemetry where possible, common BMS failure symptoms, and firmware reset/firmware update considerationsLearn to pull and read BMS data if available. Check error logs, ride counts, heat history, firmware versions, and know when to reset/update or swap hardware.
Connecting to BMS apps, tools, or adaptersReading fault codes, flags, and event logsEvaluating cycle count and SOH indicatorsFirmware reset and update risk assessmentLesson 4Li-ion battery fundamentals: cell chemistry, nominal voltages, capacity (Ah), internal resistance, and state-of-charge estimationGrasp Li-ion cell makeup, common types, and how voltage, capacity, resistance interplay. See how they impact range, power, wear, and charge level checks in workshop.
Common scooter chemistries: NMC, LFP, NCANominal, max, and cutoff voltage per cellCapacity (Ah) vs. energy (Wh) vs. C-rateInternal resistance and its measurement basicsLesson 5When to replace pack vs. repair cells: economic, safety, and longevity criteria; pros and cons of cell replacement vs. full pack replacementDecide between full pack swap or cell fix. Weigh cost, safety buffer, lifespan, labour time, liability to suggest options that guard rider and your business.
Cost comparison: parts, labor, and shop overheadRisk assessment: fire, recalls, and liabilityEstimating remaining useful life of old packsWhen to refuse repair and recommend new packLesson 6Interpreting symptoms: sudden shutdown at 40–50% and reduced range — common failure modes (capacity loss, increased internal resistance, BMS cutoff, cell group failure)Match real issues to battery faults. Analyse sudden cut-offs, short range, weak pull, shaky gauge to tell capacity drop, high resistance, BMS trip, or cell group wahala.
Patterns of range loss and voltage sagSudden cutoff at mid SOC and BMS triggersDiagnosing weak cell groups in series stringsDifferentiating pack vs. controller issuesLesson 7Battery management system (BMS) role: balancing, over/under-voltage protection, current limiting, and telemetry interfacesSee how BMS guards pack and rider. Study balancing, voltage cut-offs, current limits, heat sensing, and data links to controllers or tools.
Passive vs. active cell balancing methodsOver/under-voltage and current protectionsTemperature sensing and thermal deratingBMS data lines: CAN, UART, and proprietaryLesson 8Preliminary non-invasive checks: open-circuit voltage, resting voltage distribution, and pack voltage vs. expected valuesDo quick no-touch tests before opening. Measure open voltage, match specs, check rest voltage shift, decide on deep check or straight swap.
Measuring pack open-circuit voltage safelyComparing measured voltage to nameplate dataMonitoring resting voltage over several hoursRed flags that justify deeper investigationLesson 9Under-load and charging checks: voltage sag under load, charge acceptance, charger output verification, and charge port/connector inspectionTest battery safely on ride load and charge. Measure voltage drop, confirm charger output, charge take-up, check ports for heat, rust, damage.
Simulating real-world load with test equipmentMeasuring and interpreting voltage sagVerifying charger voltage and current outputInspecting charge ports, pins, and wiringLesson 10Battery safety and customer communication: explaining thermal runaway risk, storage/charging guidance, safe transport, and warranty/legal disclaimersBuild safe habits and clear talk with customers. Explain heat runaway danger, storage/charge rules, carry tips, and note disclaimers, waivers, warranty limits.
Recognizing and handling high-risk batteriesSafe charging, storage, and transport guidanceCustomer education scripts and checklistsDocumenting waivers and repair limitations
