Troubleshooting a golf cart

In most cases of “troubleshooting a golf cart”, the most common cause is battery-related issues – including poor plug contact, individual cell voltage mismatch, or power outage caused by BMS/low temperature protection.

Below is an 8-step troubleshooting checklist arranged from easiest to most difficult, with each step following the order: Phenomenon → Possible Causes → Solutions → Precautions.

1) Appearance and main power switch

• Symptom: There is no response when turning the key or pressing the start button (no instrument panel or lights illuminate).
• Possible causes: The main switch/circuit breaker is in the off position, the key is not turned ON, or the main battery line is loose.
• Solution: Ensure the key is in the ON position; check and turn on the main circuit breaker (usually under the seat or next to the battery); visually inspect the main cable connectors for looseness and tighten them.
• Precautions: Before operation, park the vehicle and turn off all switches; do not forcibly pull on the metal connecting parts of the cable.

2) Fuses and Circuit Breakers (Fuses)

• Symptoms: Some circuits are not working (e.g., lights are not on, meters are not moving), or there is no power at all.
• Possible causes: The main fuse or the sub-fuse has blown; the relay has not engaged.
• Solution: Locate the fuse box, check each fuse one by one, and replace the burnt fuses with the same specifications; if it is a resettable circuit breaker, try resetting it.
• Precautions: When replacing fuses, use parts of the same specification (ampere rating); frequent fuse blowouts indicate a short circuit or overload, requiring further investigation.

3) Poor contact between the charger, charging port, and plug (poor plug contact).

• Symptoms: No response after plugging in the charger, indicator light does not illuminate or charging is intermittent; the charging current fluctuates during the charging process.
• Possible causes: poor contact between the charger and the vehicle plug, oxidation of the plug or socket, or damage to the charger itself.
• Solution: Unplug and clean the plug and socket (with a clean, dry cloth or electrical contact cleaner); check the charger indicator and output, and if necessary, use a multimeter to measure the charger’s no-load output voltage; replace the faulty plug or charger.
• Precautions: Ensure the charger is disconnected from the vehicle before cleaning; avoid washing the plug with water; hold the plug body when plugging or unplugging to avoid pulling the cable.

4) Check for battery pack voltage mismatch (voltage mismatch)

• Symptoms: Inaccurate battery level display, significantly reduced battery life, and decreased power or speed on one side.
• Possible causes: Low voltage (mismatch) in some cells of the battery pack, or failure of individual cells leading to a decrease in overall performance.
• Solution: Use a multimeter to measure the voltage at each battery terminal and compare the voltage difference between adjacent batteries; if there is a significant low voltage (exceeding the manufacturer’s allowable difference), first perform equalization charging or charge the batteries individually, and then determine whether replacement is necessary.
• Precautions: Ensure correct polarity when measuring voltage; for series-connected battery packs, a problem with a single cell can affect the entire pack; record the data for later comparison.

5) Low temperature protection (low temperature protection)

• Phenomenon: When the weather is cold, the vehicle refuses to move or the charger limits the charging current, resulting in slow charging speed.
• Possible cause: The battery or BMS triggers low-temperature protection, preventing charging/discharging to protect battery life.
• Solution: Move the vehicle to a warm environment to allow the battery to warm up to its operating temperature (usually >0–5°C); some vehicles allow low-speed driving in the vehicle settings to warm the battery.
• Precautions: Do not force charging or discharge at extremely low temperatures; if the battery is operated in a low-temperature environment for a long time, its lifespan will be shortened.

6) BMS Protection and Communication Faults (BMS Protection)

• Symptoms: The instrument panel displays an error code, the charger cannot start charging, and the power is limited (reduced power mode).
• Possible causes: The BMS detects overcharge/over-discharge/cell imbalance/abnormal temperature and cuts off the output or limits the current; there is a communication problem between the BMS and the charger/controller.
• Solution: Check the vehicle manual or instrument panel codes to determine the BMS error. Try disconnecting the main power supply (disconnect the main circuit breaker or negative terminal), wait a few minutes, and then reconnect to reset. If resetting is ineffective, contact a service station with a BMS diagnostic tool to read the logs and handle the corresponding unit or sensor.
• Precautions: Do not repeatedly power off and reset without knowing the reason, as this may mask the protective disconnection that is in progress; if you need to replace the BMS or its sensors, please use original or compatible parts.

7) Charger body and voltage output issues (charger malfunction)

• Symptoms: The charger shows an indicator when connected but has no output voltage or the output voltage does not match the nameplate; the charger overheats abnormally.
• Possible causes: Damage to internal components of the charger (rectifier, control board, temperature control probe failure), or the output voltage does not match the nominal voltage of the battery pack (voltage mismatch).
• Solution: Use a multimeter to measure the charger’s output open-circuit voltage and load voltage to confirm that they match the nameplate parameters; if they do not match, or if the charger is overheating or emitting a smell, stop using it and replace or send it for repair.
• Precautions: The charger contains high voltage. Do not disassemble it if you are not a professional. Ensure that the voltage/current parameters of the replacement charger are compatible with the battery pack.

8) Controller, grounding, and motor level testing (more complex)

• Symptoms: Intermittent power supply, “clicking” sound from the relay, or abnormal current after power is applied.
• Possible causes: controller malfunction, poor grounding, relay contact burnout, or high-resistance connection causing current limitation.
• Solution: Check the main line contact between the controller and the battery, and whether the cable is overheating; check whether the grounding wire and vehicle grounding are secure; use an oscilloscope or current clamp to measure the control signal (preferably by a professional technician).
• Precautions: This step involves high current and electronic control modules. If you are not familiar with them, please leave it to a professional technician. Record the original wiring and location during the repair to avoid incorrect wiring.

9) Battery aging and capacity testing (final judgment)

• Phenomenon: The battery life decreases significantly after a single charge, and the voltage drops rapidly after multiple charge and discharge cycles.
• Possible causes: battery aging, severe capacity degradation, or internal short circuit.
• Solutions: Perform a battery capacity test (discharge test), or replace the battery pack one by one to locate the faulty cell; if most batteries have severely degraded, consider replacing the entire pack.
• Precautions: When replacing batteries, consider those of the same brand, capacity, and age to avoid voltage mismatch and accelerated degradation; lithium batteries must be configured according to BMS requirements.

When should the charger be replaced?

• The charger is not outputting anything or the output voltage/current does not match the nameplate parameters for an extended period.
• The charger overheats abnormally, smokes, or smells burnt when operating at normal temperature.
• The charger’s communication with the battery/vehicle (e.g., CAN, communication port) is damaged and cannot be repaired;
• Professional testing confirmed that the charger’s internal key components (rectifier, control module, or temperature sensor) were beyond repair and that the repair cost was close to or higher than the replacement cost.

Three criteria for choosing a charger (recommended)

1. Voltage and current matching: The selected output voltage must be fully matched with the nominal voltage of the battery pack (e.g., 36V/48V/72V), and the maximum output current (A) should match the charging rate recommended by the battery manufacturer (usually expressed as C-rate).
2. Battery type and communication support: Confirm that the charger’s charging curve/algorithm is suitable for your battery chemistry (lead-acid, AGM, lithium iron phosphate, etc.). For lithium batteries, prioritize chargers with BMS communication/balancing interfaces for safe management.
3. Safety and Reliability: Choose products with overcharge, overcurrent, and short-circuit protection, temperature compensation, and relevant certifications (such as UL/CE). Brand and warranty policies are also crucial. For outdoor use, pay attention to the waterproof rating (IP rating).

If you’d like, I can provide a more specific checklist based on your golf cart brand, voltage, and battery type, or recommend a few well-regarded chargers. Would you like me to send you your cart model and battery information?