why is my cart not charging

The most common cause is poor contact or loose connection between the charger and the vehicle plug, resulting in unstable charging current or no charging at all.

Investigation steps (from easiest to hardest to check):

1) First check the power and charger indicator lights.

• Symptom: The charger has no indicator lights, or the indicator lights are not lit at all.
• Possible causes: No power to the wall socket/extension cord, garage circuit breaker tripped, charger power cord broken.
• Solutions: Test the same socket with a phone charger or electric drill; check and reset the circuit breaker; try switching to another known powered socket.
• Precautions: Unplug the charger before operating the socket; avoid touching the plug directly in humid environments.

2) Check the contact between the charger and the vehicle plug (poor plug contact).

• Phenomenon: The charging process is intermittent; the charging resumes or the indicator light flashes when the plug is gently shaken.
• Possible causes: plug oxidation, dirt, spring fatigue or pin deformation, loose socket.
• Solution: With the power off, clean the contacts (using a dedicated contact cleaner or 38# alcohol), calibrate the pins, and ensure the plug is fully inserted and secured; replace the worn plug or socket if necessary.
• Precautions: Disconnect the power before cleaning; do not excessively sand the plating; applying a small amount of insulating and anti-rust lubricant to the contact surfaces can extend their lifespan.

3) Check the fuses/circuit breakers in the vehicle and charger.

• Symptom: The charger stops working immediately after being plugged in, or trips the circuit breaker/stops charging after a short while.
• Possible causes: The main fuse inside the charger or in the vehicle has blown; the overcurrent protection has tripped.
• Solution: Locate and replace the corresponding fuse (according to the instruction manual or original manufacturer’s specifications), and check if there is a short circuit causing frequent fuse blowouts; if it is a resettable circuit breaker, reset it first and then observe.
• Important: When replacing a fuse, you must use a model with the same current rating. Do not arbitrarily replace it with one of a higher amperage rating to “solve the problem”.

4) Measure the charger output (to determine if the charger is faulty).

• Symptom: The charger indicator light is abnormal (red/yellow light error code), or the measured output voltage is zero.
• Possible causes: Faulty internal components of the charger (transformer, rectifier, control board, etc.), or the fan not turning, causing the protection to shut down.
• Solution: Use a multimeter to measure the DC/AC voltage at the charger’s output terminal (according to the instruction manual) and compare it with the nominal output; if there is no output or the value is obviously abnormal, the charger needs to be repaired or replaced.
• Precautions: Ensure safe operation before measurement. Measuring with the charger on is dangerous. It is not recommended for non-professionals to disassemble and repair the high-voltage part.

5) Check the total voltage of the battery pack and the voltage of each individual cell (voltage mismatch/cell depletion).

• Symptoms: The total voltage of the battery pack is abnormally low or unstable; the charger is working but the voltage rises very slowly or fails to reach the expected voltage.
• Possible causes: Some individual cells are severely depleted or have high internal impedance, leading to voltage imbalance within the group; voltage mismatch between series-connected cells.
• Solution: Measure the terminal voltage of each battery individually, identify and replace batteries with low or reverse voltage; for lead-acid batteries, try equalization charging or individual cell float charging before reconnecting them for use.
• Precautions: Pay attention to the polarity when testing the battery; when replacing the battery, be sure to use the same brand, capacity and specifications of the same type. Mixing batteries will accelerate the imbalance.

6) Check BMS protection (battery management system cuts off charging).

• Symptoms: After the charger is connected, the instrument displays a BMS error code, charging stops momentarily, or charging cannot be performed for an extended period of time.
• Possible cause: The BMS detects overvoltage/undervoltage/overtemperature/communication failure or short circuit and automatically cuts off the charging output to protect the battery.
• Troubleshooting: Check the instrument or fault code manual, and try powering off and restarting the BMS as instructed by the manufacturer (disconnect the power for a few minutes and then reconnect it); check the individual battery cells and communication harness; if the fault is in the BMS itself, contact a professional repairman or replace the BMS.
• Precautions: Do not attempt to bypass or short-circuit the BMS to force charging, as this can easily damage the battery and create safety risks.

7) Low temperature protection prevents charging.

• Symptoms: The charger fails to start charging or stops charging midway in cold environments; the meter or charger displays temperature protection related prompts.
• Possible cause: The battery/charger has low temperature protection (the BMS or charger detects that the temperature is below the safe charging threshold).
• Solutions: Move the golf cart to a warm environment to allow the battery to return to the manufacturer’s recommended charging temperature range before charging; cover it to keep it warm or slowly warm it up to a safe temperature; check the location of the temperature sensor and the wiring connection.
• Precautions: Avoid direct heating of the battery with open flame or high-temperature appliances; do not force charging at low temperatures to avoid polarization or sulfation.

8) Charger and battery pack voltage/type mismatch (voltage mismatch)

• Symptoms: The charger displays an error message very quickly after being connected, the charging time is abnormally short, or the voltage is abnormally high/low when fully charged.
• Possible cause: The charger’s output voltage or charging curve is incompatible with the vehicle’s battery pack (e.g., a 6V/8V/12V series combination or lead-acid and lithium batteries).
• Solution: Check the rated voltage of the vehicle’s battery pack against the charger specifications (V and A); if they do not match, replace the charger with one that matches the battery type (lead-acid/AGM/lithium) and pack voltage.
• Precautions: Do not use a charger with a voltage higher than the rated voltage of the battery pack; different battery chemistry systems require corresponding charging curves and termination voltages.

9) Deeper-level faults (contactor, wiring harness, charging interface, or BMS software issues)

• Symptoms: If the above troubleshooting is unsuccessful, or if sparks, heat, odor, or persistent error codes occur during charging.
• Possible causes: stuck contactor/relay in the vehicle, open circuit or short circuit inside the main wiring harness, damaged charging socket, or BMS firmware/communication module failure.
• Solution: Stop attempting to charge the vehicle and take it to an experienced repair shop for load testing, thermal imaging, and segment-by-segment electrical diagnostics; replace damaged components or update the BMS software if necessary.
• Precautions: These inspections often involve high voltage and specialized instruments. Non-professionals should not disassemble high-voltage circuits. If you smell a burning odor or see smoke, immediately disconnect the power and contact professional rescue.

When should the charger be replaced?

• The charger was measured to have no output or a continuously unstable output, the fan was not turning and was accompanied by abnormal temperature rise or a burning smell.
• The same fault occurs repeatedly (e.g., the fuse still blows after replacement, cleaning the contacts is ineffective), and the charger is old (it has been used for many years and the manufacturer recommends that it has reached the end of its lifespan).
• The charger is severely incompatible with the existing battery system (for example, you have converted to lithium batteries but are still using a charger designed for lead-acid batteries), or the manufacturer has stopped supporting it and cannot fix it.

Three criteria for selecting a charger: 1) Voltage and current matching and support for battery chemistry: The charger’s nominal voltage must match the battery pack’s rated voltage, and the output current (A) should meet charging time requirements and match the battery manufacturer’s recommended range; confirm that the charger supports lead-acid/AGM/lithium and other corresponding chemistry systems and charging curves. 2) Complete protection and communication functions: Prioritize chargers with overvoltage/overcurrent/overtemperature/short circuit protection, temperature sensor input, and BMS communication capabilities, as these can reduce the risk of mischarging and damage. 3) Brand and certification, warranty and after-sales service: Choose products from reliable manufacturers, with safety certifications (such as CE/UL), and offering reasonable warranty and parts support; also confirm that the output interface is compatible with the vehicle’s plug or that the interface is easily replaceable.