Lesson 1Battery repair process workflow: isolation, safe disassembly, cell verification, balancing, reassembly, and test cycleFollow a safe step-by-step battery fix process. Practice disconnecting, opening packs, checking cells and welds, swapping bad ones, balancing, sealing up, and testing before handing back.
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 imbalancesLearn deep cell tests like resistance checks, load tests for capacity, spotting uneven groups, and deciding which cells to save or scrap for cost and safety.
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 considerationsFind and read BMS data if you can. Check error logs, ride counts, heat history, software versions, and know when to reset, update, or just replace the board.
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 how Li-ion cells work, their chemistries, voltages, capacity, resistance, and how these shape range, power, wear, and charge reads in your 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 smartly between full battery swap or cell fixes by weighing costs, safety, life span, time, and risks to keep riders safe and your business 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 scooter woes like early cut-offs or short range to battery faults. Tell apart low capacity, high resistance, BMS trips, 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 the battery and rider with balancing, voltage limits, current caps, heat checks, and data links to controllers.
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 easy no-cut tests first: measure open voltage, check cell spreads, match to specs, and decide on next steps 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 batteries under power and charge safely. Check voltage drops, charger strength, take-up, and port condition for heat or rust.
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 tell customers straight about fire risks, storage tips, carry rules, and what warranties cover or don't.
Recognizing and handling high-risk batteriesSafe charging, storage, and transport guidanceCustomer education scripts and checklistsDocumenting waivers and repair limitations
