Introduction

Firmware updates can improve:

• Battery compatibility
• Communication stability
• Charging algorithms
• Monitoring
• Grid-code compliance
• Inverter functions
• Fault detection
• Cybersecurity
• System performance

However, an uncontrolled update can also create new problems.

Customers may report that after an update:

• The inverter no longer recognizes the battery.
• Battery SOC shows 0% or 100%.
• Charging current is limited unexpectedly.
• Battery charging stops.
• Inverter returns to lead-acid mode.
• CAN communication fails.
• Parallel batteries disappear from the system.
• Time-of-use settings are lost.
• Backup output no longer works.
• Low-voltage settings change.
• The inverter repeatedly restarts.

Firmware should therefore be managed as an engineering change—not as a routine mobile-phone application update.

Official inverter support documentation sometimes requires firmware updates specifically to match battery protocols or improve integration stability.

What Is Firmware?

Firmware is the internal software that controls equipment hardware.

An energy storage system may contain separate firmware in:

• Inverter DSP
• Inverter HMI
• Battery BMS
• Battery master controller
• Battery display
• Wi-Fi or LAN data logger
• Smart meter
• Energy management system
• Parallel-inverter controller
• Automatic transfer switch
• MPPT controller

Updating one component can affect the communication or behaviour of another.

Why Battery Compatibility Can Change

Battery–inverter compatibility depends on more than electrical voltage.

It may also depend on:

• CAN message format
• RS485 register map
• CAN ID
• Baud rate
• SOC scaling
• Charging-current command
• Discharge-current command
• Alarm-bit definition
• Number of battery modules
• Firmware response timing
• Wake-up sequence
• Communication timeout

A new inverter firmware version may change:

• Supported battery list
• Protocol selection names
• Error handling
• Charging logic
• Communication timeout
• Default battery settings

A new BMS firmware version may change the messages sent to the inverter.

This is why an update that improves one combination may require validation with another.

Prevention Step 1: Do Not Update Without a Specific Reason

Valid reasons may include:

• Manufacturer safety notice
• Confirmed compatibility requirement
• Known communication fault
• Grid-code requirement
• Required battery support
• Approved performance improvement
• Technical-support instruction
• Cybersecurity correction

Avoid updating solely because a newer number appears in an application.

Before updating, ask:

• What problem does the update solve?
• Is the current system operating normally?
• Is the new version approved for this battery?
• Can the previous version be restored?
• Does the update reset settings?
• Does it require a particular update order?
• Is on-site access required if the update fails?

Prevention Step 2: Confirm the Complete Compatibility Matrix

Record:

• Inverter model
• Inverter serial number
• Inverter hardware version
• DSP firmware
• HMI firmware
• Battery model
• Battery BMS brand
• Battery BMS firmware
• Battery display firmware
• Master BMS version
• Communication protocol
• Number of battery modules

Then confirm the approved combination with:

• Inverter manufacturer
• Battery supplier
• Authorized distributor
• Current compatibility list

Solis support resources, for example, maintain battery compatibility information and firmware-upgrade guidance for matching supported battery protocols.

Do not assume that compatibility with one inverter in a product series automatically covers every power rating and regional version.

Prevention Step 3: Save Every Setting Before the Update

Take screenshots or export settings for:

Battery Settings

• Battery type
• Communication protocol
• Battery capacity
• Maximum charging current
• Maximum discharge current
• Charging voltage
• Low-voltage shutdown
• Restart voltage
• Minimum SOC
• Backup reserve

Energy Settings

• Self-consumption mode
• Time-of-use schedule
• Grid-charging permission
• Forced charge periods
• Forced discharge periods
• Export limit
• Peak-shaving power
• Generator settings

System Settings

• Grid code
• AC voltage
• Frequency
• Meter model
• CT ratio
• Meter placement
• Backup mode
• Parallel-inverter role
• Phase settings

Communication Settings

• CAN or RS485
• Battery address
• Modbus address
• Baud rate
• Data-logger settings

Take photographs of physical DIP switches as well.

Prevention Step 4: Download the Correct Firmware Package

Confirm:

• Exact inverter model
• Region
• Grid version
• Hardware revision
• Power rating
• Single-phase or three-phase design
• Low-voltage or high-voltage battery version
• File type
• Update tool
• Required intermediate version

Installing firmware for a similar but different model can make the inverter unusable.

Use only:

• Official manufacturer portal
• Authorized service platform
• File supplied by qualified technical support

Do not use firmware obtained from an online forum, messaging group or another customer.

Prevention Step 5: Follow the Required Update Order

Some systems require updating:

1. Battery BMS
2. Battery master controller
3. Inverter DSP
4. Inverter HMI
5. Data logger

Another system may require a different order.

Follow the manufacturer’s update document.

Updating only one component may create temporary incompatibility.

Official Solis procedures distinguish different inverter firmware components, including HMI and DSP updates, which illustrates why the complete manufacturer procedure matters.

Prevention Step 6: Prepare a Stable Power Source

Firmware interruption can occur if:

• Battery enters low-SOC shutdown.
• Grid power fails.
• Inverter is switched off.
• Wi-Fi connection drops.
• Mobile phone loses power.
• Generator stops.
• Communication cable is removed.

Before updating:

• Charge the battery to a safe SOC.
• Confirm stable grid supply where required.
• Keep essential update equipment powered.
• Avoid updating during thunderstorms.
• Avoid periods of expected grid interruption.
• Stop non-essential loads.
• Confirm remote-access stability.
• Maintain local technician access for critical systems.

The update instructions may specify whether PV, battery or AC power must remain connected.

Prevention Step 7: Place the System in a Safe Operating State

Depending on the manufacturer, this may require:

• Stop charging.
• Stop discharging.
• Disconnect large loads.
• Disable time-of-use operation.
• Stop the generator.
• Maintain grid bypass.
• Keep battery communication connected.
• Open specific breakers.
• Keep specific power supplies active.

Do not invent a shutdown sequence.

Follow the update instructions for the exact equipment.

Prevention Step 8: Update One System at a Time

For sites with several inverters or battery clusters:

• Identify each unit.
• Update one approved group.
• Verify operation.
• Continue to the next group.

Updating every unit simultaneously can cause:

• Complete site shutdown
• Loss of monitoring
• Difficult fault isolation
• Mixed firmware within a cluster
• Parallel communication failure

For redundant systems, maintain service capacity where the design permits.

Prevention Step 9: Do Not Interrupt the Update

During the firmware process:

• Do not switch off battery power.
• Do not close the application.
• Do not remove the update device.
• Do not disconnect Wi-Fi intentionally.
• Do not operate breakers.
• Do not restart the inverter unless instructed.
• Do not begin another update.

If progress appears frozen, follow the manufacturer’s recovery procedure rather than cycling power randomly.

Prevention Step 10: Check Whether Settings Were Reset

After the update, verify every saved parameter.

Pay special attention to:

• Battery type changed to default
• Protocol returned to another brand
• Battery capacity reset
• Charging current returned to maximum
• Low-voltage threshold changed
• Grid charging enabled
• Backup reserve changed
• Time-of-use schedule deleted
• CT ratio reset
• Meter direction setting changed
• Export limit disabled
• Grid code reset

A successful firmware upload does not prove that the system is correctly recommissioned.

Prevention Step 11: Reconfirm Battery Communication

After the update, verify:

• Battery online
• CAN or RS485 normal
• Correct SOC
• Correct battery voltage
• Correct temperature
• Correct battery quantity
• Correct charging-current limit
• Correct discharge-current limit
• No alarm bits
• Correct master battery

If communication fails:

1. Do not immediately change several settings.
2. Record the error code.
3. Confirm protocol selection.
4. Confirm cable and port.
5. Confirm addresses.
6. Confirm firmware versions.
7. Follow technical-support instructions.

The HIZN website already identifies firmware mismatch as one cause of battery communication failures.

Prevention Step 12: Reconfirm Parallel Battery Addresses

Battery updates may affect:

• DIP-switch interpretation
• Master/slave selection
• Address table
• Termination settings
• Maximum module number
• Battery discovery sequence

Verify that:

• Every battery has a unique address.
• One battery is selected as master.
• Communication cables are connected in sequence.
• Termination is installed where required.
• All modules use compatible firmware.
• Total battery capacity is correct.

Avoid operating one cluster with mixed BMS firmware unless the battery supplier approves it.

Prevention Step 13: Recheck Smart Meter and CT Data

After an inverter update, confirm:

• Meter communication
• CT direction
• CT ratio
• Phase assignment
• Grid import
• Grid export
• Load value
• Zero-export response

A reset meter setting can make the battery charge or discharge incorrectly even when battery communication is normal.

Prevention Step 14: Test Charging at Low Current First

Do not begin with maximum solar or generator charging.

Start at moderate current and monitor:

• Battery voltage
• Highest cell voltage
• Lowest cell voltage
• Charging-current request
• Actual charging current
• Battery temperature
• Inverter alarm history

Then increase current gradually.

This helps identify incorrect charging limits before the BMS enters hard protection.

Prevention Step 15: Test Discharging Gradually

Use:

1. Light load
2. Moderate load
3. Normal operating load
4. Approved high load
5. Largest motor start where required

Confirm:

• BMS current limit
• Inverter output
• Battery voltage
• Communication stability
• No unexpected shutdown

Do not declare the update successful after only checking the display.

Prevention Step 16: Test Backup Operation

Simulate a grid outage and confirm:

• Backup output remains active.
• Battery discharge is permitted.
• Transfer operation is normal.
• Critical loads are supplied.
• Grid isolation works.
• Battery SOC reserve is correct.
• Grid reconnection is normal.

An update may affect backup parameters even when on-grid operation appears normal.

Prevention Step 17: Test Restart After Full Shutdown

Perform:

1. Controlled shutdown
2. Wait for inverter DC bus to discharge
3. Battery-only restart where supported
4. Grid-assisted restart
5. PV restart
6. Communication recovery

This confirms that the system will restart after a real outage rather than only after a software reboot.

Prevention Step 18: Monitor for Several Complete Cycles

Some update problems appear only when the system:

• Reaches full charge
• Reaches minimum SOC
• Enters a tariff period
• Starts the generator
• Changes from on-grid to off-grid
• Balances cells
• Loses cloud connection
• Operates at high power

Monitor at least:

• One full charging period
• One overnight discharge
• One backup test
• One time-of-use transition
• One high-load period

Critical commercial sites may require longer validation.

Recommended Post-Update Test Table

Test Item	Expected Result	Actual Result
Battery communication	Normal	Record
Battery quantity	All modules detected	Record
SOC display	Consistent	Record
Charge-current limit	Matches BMS	Record
Discharge-current limit	Matches BMS	Record
Solar charging	Stable	Record
Grid charging	Follows schedule	Record
Time-of-use discharge	Correct period	Record
Backup operation	Critical loads maintained	Record
Meter direction	Import/export correct	Record
Full-charge behaviour	No repeated overvoltage cycling	Record
Low-SOC shutdown	Controlled	Record
Restart	Normal	Record

Create a Rollback Plan

Before updating, know:

• Is downgrade permitted?
• Is the old firmware file available?
• Can rollback be performed remotely?
• Does rollback reset settings?
• Is manufacturer authorization required?
• What happens if the inverter will not start?
• Is a local service tool required?

Some manufacturers may not permit arbitrary downgrade because of grid-code or safety requirements.

Do not attempt rollback without technical approval.

Keep an Update Record

Record:

• Update date
• Technician
• Reason for update
• Previous firmware
• New firmware
• File source
• Battery firmware
• Inverter firmware
• Settings backup
• Test results
• Problems found
• Technical-support case number

For distributor projects, keep records by:

• Customer
• Inverter serial number
• Battery serial number
• Production batch
• Country
• Installation date

This helps identify whether an issue affects one site or a complete product batch.

Remote Updates Require Additional Control

Before a remote update:

• Confirm someone can access the site.
• Confirm the customer understands possible downtime.
• Ensure critical loads have alternative supply.
• Verify stable internet.
• Save settings remotely.
• Confirm the local emergency contact.
• Avoid updating before a holiday or weekend without support.

Do not remotely update a critical off-grid site when no local recovery method exists.

Common Prevention Mistakes

Updating Because a New Version Exists

The update may not be necessary for a stable system.

Using Firmware for a Similar Model

Hardware and regional differences can matter.

Failing to Save Settings

The system may restart with unsuitable defaults.

Updating the Inverter but Not Checking the Battery Protocol

Communication may fail.

Updating All Parallel Units Simultaneously

Fault isolation becomes difficult.

Testing Only the Display

Charging, discharging and backup functions may still be wrong.

Ignoring the Smart Meter

Reset meter settings can change battery behaviour.

Allowing Mixed Battery Firmware

Parallel modules may report data differently.

No Rollback Plan

Recovery becomes dependent on manufacturer intervention.

Frequently Asked Questions

Should I always install the latest inverter firmware?

Not automatically. Use the version approved for the specific inverter, battery and regional configuration.

Can firmware damage the battery cells?

Firmware does not directly change cell chemistry, but incorrect charging or discharge control after an update can cause protection events or unsuitable operation.

Why did battery communication disappear after updating?

The protocol selection may have reset, firmware versions may be incompatible, or communication settings may have changed.

Can I update the battery BMS myself?

Only when the battery supplier provides an approved tool, file and procedure.

Will an update erase time-of-use settings?

Some updates retain settings, while others reset some or all parameters. Save every setting first.

Can firmware be downgraded?

This depends on the manufacturer, hardware and safety requirements. Obtain approval before attempting it.

How do I know the update was successful?

Successful upload is only the first step. Verify communication, charging, discharging, backup, meter data and restart behaviour.

Conclusion

Firmware updates can improve a LiFePO4 battery and inverter system, but they should be managed as controlled engineering changes.

A safe update process includes:

• Clear reason for the update
• Confirmed compatibility matrix
• Complete settings backup
• Correct firmware package
• Approved update sequence
• Stable power and communication
• Reverification of every setting
• Battery communication test
• Meter and CT test
• Controlled charging and discharge tests
• Backup and restart tests
• Several operating-cycle observations
• Rollback plan
• Complete update records

For HIZN Lithium firmware and compatibility support, provide:

• Battery model
• Battery serial number
• BMS brand
• Current BMS firmware
• Inverter brand and model
• Inverter serial number
• Current DSP and HMI versions
• Communication protocol
• Battery quantity
• Error screenshots
• Reason for the requested update

This information allows the battery and inverter combination to be reviewed before any firmware is changed.