Lesson 1Battery repair process workflow: isolation, safe disassembly, cell verification, balancing, reassembly, and test cycleFollow safe steps to fix batteries. Practice cutting power, opening packs, checking welds and covers, swapping cells, balancing charge, sealing up, and testing before giving back the scooter.
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 testing single cells. Measure inside resistance, guess capacity with load tests over time, find uneven cell groups, and pick which ones to save or scrap.
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 read BMS data if you can. Check error logs, ride counts, heat history, software versions, and know when to reset or update safely or swap the 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, types, and how voltage, capacity, resistance link up. See how they shape ride distance, power, wear, and charge level checks in the shop.
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 pack swap or cell fix by cost, safety, life span, work time, risks. Weigh options to keep rider safe and your shop solid.
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 signs to battery woes. Check sudden stops, short rides, weak speed, odd gauges to spot low capacity, high resistance, BMS blocks, or bad cell groups.
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 charge balancing, voltage cutoffs, current caps, heat checks, and data links to controls 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-cut tests before opening. Measure open voltage, match specs, check rest voltage shifts, decide 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 safe while riding loaded and charging. Measure voltage drop, check charger power, charge take-up, inspect ports for heat, rust, harm.
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 dangers, store and charge rules, move tips, note waivers and warranty limits.
Recognizing and handling high-risk batteriesSafe charging, storage, and transport guidanceCustomer education scripts and checklistsDocumenting waivers and repair limitations
