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Bluetti•AC500

Analysis by Marcus & Team

Bluetti AC500 Error E035 Bus Overvoltage

Troubleshoot Bluetti AC500 E035 error: Bus overvoltage. Find causes, solutions, and safety tips for your residential energy storage system.

Frequently Asked Questions

•What is the DC bus voltage specification for the AC500?

Refer to the Bluetti AC500's technical manual for the specific DC bus voltage range. Typically around 400VDC.

•How do I perform a firmware update on the AC500?

Firmware updates are typically performed through the Bluetti mobile app or via a USB drive. Refer to the Bluetti user manual for detailed instructions.

•What should I do if the AC500 is still under warranty?

Contact Bluetti support immediately and provide them with the error code and any diagnostic information you have gathered. Follow their instructions for warranty claims and repair procedures.

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Marcus leads the technical research department at Storage Faults. Together with a team of systems analysts, he specializes in translating complex solar storage error codes into actionable diagnostic steps for the US market.

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Observed Symptoms:

AC500 displays error code E035, shuts down, or exhibits erratic behavior. Inverter ceases AC output, and battery charging may be disabled. System may disconnect from the grid to prevent damage. LCD screen displays 'Bus Overvoltage' message.

Important Warnings:

The Bluetti AC500 contains high-voltage DC components (up to 600VDC). Improper handling can result in severe electric shock or arc flash. Only qualified electricians should perform internal diagnostics or repairs. Always disconnect all power sources before performing any maintenance.

Step-by-Step Fix:

1

*Safety First**: Disconnect the AC500 from both AC and DC power sources following NEC 690.15 disconnect procedures. Ensure rapid shutdown is activated per NEC 2017/2020 requirements.
2

*Visual inspection**: Inspect the AC500 for signs of physical damage, such as bulging capacitors, burnt components, or loose wiring within the unit's internal components. Only qualified technicians should perform this step.
3

*Voltage Measurement (Qualified Personnel Only)**: Using a calibrated multimeter, carefully measure the DC bus voltage after disconnecting all power sources. Compare the reading to the AC500's specifications (typically around 400VDC). If voltage is above the spec after complete shutdown, a component failure is indicated.
4

*Firmware Update**: If no hardware damage is apparent, attempt a firmware update using the Bluetti mobile app or a USB drive. Ensure the update is compatible with your specific AC500 model. Faulty firmware can sometimes trigger false overvoltage errors.
5

*Battery Voltage Check**: Use a multimeter to measure the voltage of the connected battery bank. Ensure the voltage is within the manufacturer's recommended range and that no individual battery is significantly overcharged.
6

*Isolate Solar Input**: Disconnect any solar panels connected to the AC500. If the error clears after disconnecting solar input, the issue might be related to MPPT malfunction or incorrect PV array configuration.
7

*Consult Bluetti Support**: Contact Bluetti's technical support with the error code and diagnostic findings. They may provide specific troubleshooting steps or authorize an RMA if the unit is under warranty.

Technical Overview:

The AC500 utilizes a DC bus to link the battery, solar charge controller (MPPT), and AC inverter stages. This bus operates at a specific voltage range (e.g., 400VDC). Error E035 indicates the DC bus voltage has exceeded its upper limit, triggering a protective shutdown. This can be caused by regenerative braking from motors, incorrect voltage settings, or component failure within the power electronics.

Common Causes:

Faulty voltage sensor within the DC bus monitoring circuit, providing an inaccurate high voltage reading.
Overcharging of the battery bank leading to excessive voltage on the DC bus.
Grid instability causing voltage spikes reflected onto the DC bus during AC coupling.
Defective capacitor(s) within the DC bus filter network, failing to dampen voltage fluctuations.
Software or firmware glitch causing misinterpretation of voltage levels.
Failure of the MPPT charge controller, pushing excessive voltage onto the DC bus.

Technical Recommendation:

Access the Bluetti AC500's service menu (if available and accessible) by pressing and holding the "Display" and "Enter" buttons simultaneously for 5 seconds. This may reveal detailed voltage logs and error history that can help pinpoint the source of the overvoltage error.

Preventative Care:

Regularly monitor the AC500's performance via the monitoring app. Pay attention to voltage and current readings.
Ensure the AC500 firmware is up-to-date.
Periodically check the battery bank's state of health (SOH) to identify potential overcharging issues.
Keep the AC500 clean and free from dust and debris to prevent overheating.
Ensure proper ventilation around the unit.