MARS I PLUS troubleshooting and alarm codes
This page reproduces Appendix B, Alarm Code Index and section 7.2 of the MARS I PLUS user manual V1.4. Alarms show on the EMS display panel and in the app's event logs.
Installer / authorised service only
The manual says: "Contact your installer or authorized service provider if the issue persists or for any operations you are not qualified to perform" and "DO NOT attempt to resolve the alarm by disassembling the system or ignoring the instructions." The MARS I PLUS has a 400 V battery and up to 550 V PV input. After switching off, wait at least 10 minutes for internal capacitors to discharge. Homeowners should only do the simple steps (restarting, reducing load, waiting for the grid) and leave everything else to the installer.
General procedure (manual section 7.2)
- Look up the alarm code in the table below for its meaning and recommended actions.
- If the issue continues, or the step needs qualified work, contact your installer or authorised service provider.
- Never disassemble the system to clear an alarm.
The manual's section 7.2 refers to "Appendix C - Alarm Code Index", but the alarm index is actually Appendix B. Appendix C is the language list.
"Restart (5 min)" below is short for the manual's: "Turn the inverter off, wait for 5 minutes, and restart. If the problem persists, contact the manufacturer for technical support."
Alarm-code index
PV, bus and internal (001–012)
| Code | Alarm | Possible cause | Suggestions |
|---|---|---|---|
| 001 | Insulation Fault | 1. Not enough insulation between PV panels and ground. 2. Internal inverter failure. | 1. Check all wiring for damage and verify insulation between PV panels and ground. 2. Restart (5 min) and see if it runs normally. 3. If it persists, contact the manufacturer. |
| 002 | PV Overvoltage | 1. PV string voltage is above the system's maximum input voltage. 2. Internal inverter failure. | 1. Check that the number of PV panels in a string is within specification. 2. If the configuration is correct, restart (5 min). 3. If it persists, contact the manufacturer. |
| 003 | PV Overcurrent | 1. PV array struck by lightning. 2. Internal inverter failure. | 1. Restart (5 min). 2. If it doesn't return to normal, contact the manufacturer. |
| 004 | Bus Overvoltage | 1. Abnormal grid-voltage fluctuation. 2. Too many PV panels in series. 3. Internal inverter failure. | 1. Turn the inverter off and check the PV string configuration and grid voltage. 2. If no issues are found, wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
| 005 | Bus Undervoltage | 1. Not enough energy from PV and battery while running off-grid. 2. Internal inverter failure. | 1. Check the battery level and PV generation. 2. If energy is low, connect to the grid and check it runs normally. 3. If it persists, contact the manufacturer. |
| 006 | Bus Unbalance | 1. Connected load is very unbalanced. 2. Internal inverter failure. | 1. Remove all loads and check whether the system returns to normal. 2. Restart (5 min). 3. If it persists, contact the manufacturer. |
| 007 | Relay Fault | Internal inverter failure. | Restart (5 min). |
| 008 | PV Overtemperature | 1. Heat sink is blocked. 2. Ambient temperature too high. 3. Internal inverter failure. | 1. Turn the inverter off, check the heat sink, and let it cool before restarting. 2. If it persists, contact the manufacturer. |
| 009 | Communication Fault | Internal inverter failure. | Restart (5 min). |
| 010 | Storage Fault | Internal inverter failure. | Restart (5 min). |
| 011 | PV Reverse Polarity | 1. PV positive and negative cables reversed. 2. Internal inverter failure. | 1. Turn the inverter off, check the PV cable polarity, wait 5 minutes and restart. 2. If it persists, contact the manufacturer. |
| 012 | Sampling Error | Internal inverter failure. | Restart (5 min). |
Grid (013–022)
| Code | Alarm | Possible cause | Suggestions |
|---|---|---|---|
| 013 | Grid Overfrequency | 1. Abnormal local grid frequency. 2. Internal inverter failure. | 1. Wait for the grid frequency to return to the normal range. 2. If it doesn't recover for a long time, contact the manufacturer. |
| 014 | Grid Underfrequency | 1. Abnormal local grid frequency. 2. Internal inverter failure. | 1. Wait for the grid frequency to return to the normal range. 2. If it doesn't recover for a long time, contact the manufacturer. |
| 015 | Grid Overvoltage | 1. Abnormal local grid voltage. 2. Internal inverter failure. | 1. Wait for the grid voltage to return to the normal range. 2. If it doesn't recover for a long time, contact the manufacturer. |
| 016 | Grid Undervoltage | 1. Abnormal local grid voltage. 2. Grid not connected. 3. Internal inverter failure. | 1. Wait for the grid voltage to return to normal. 2. Check that the grid is properly connected. 3. If it doesn't recover for a long time, contact the manufacturer. |
| 017 | Abnormal Grid Voltage Ride-Through | 1. Abnormal local grid voltage. 2. Grid not connected. 3. Internal inverter failure. | 1. Wait for the grid voltage to return to normal. 2. Check that the grid is properly connected. 3. If it doesn't recover for a long time, contact the manufacturer. |
| 018 | Abnormal Grid Frequency | 1. Abnormal local grid frequency. 2. Internal inverter failure. | 1. Wait for the grid frequency to return to normal. 2. Power off, wait 5 minutes and restart. 3. If it doesn't return to normal, contact the manufacturer. |
| 019 | Abnormal Grid Voltage | 1. Abnormal local grid voltage. 2. Grid not connected. 3. Internal inverter failure. | 1. Wait for the grid voltage to return to normal. 2. Check that the grid is properly connected. 3. If it doesn't recover for a long time, contact the manufacturer. |
| 020 | Grid Phase Sequence Fault | 1. Three-phase grid not correctly connected to the inverter. 2. Internal inverter failure. | 1. Check that the three-phase grid is correctly connected to the inverter. 2. If the phase sequence is correct and the fault remains, contact the manufacturer. |
| 021 | Islanding Protection | 1. Local grid fault detected. 2. Internal inverter failure. | 1. Power off the unit and check whether the local grid voltage is normal. 2. Wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
| 022 | Grid Loss | 1. Local grid failure. 2. Internal inverter failure. | 1. Power off the unit and check whether the local grid voltage is normal. 2. Wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
Inverter (023–036)
| Code | Alarm | Possible cause | Suggestions |
|---|---|---|---|
| 023 | Inverter Overcurrent | 1. Short circuit at the LOAD terminals. 2. Abnormal local grid. 3. Internal inverter failure. | 1. Power off the unit and check the output terminals for a short circuit. 2. Wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
| 024 | Inverter Overvoltage | 1. Abnormal local grid voltage. 2. Internal inverter failure. | 1. Power off, wait 5 minutes and restart. 2. If it persists, contact the manufacturer. |
| 025 | Inverter Undervoltage | Internal inverter failure. | 1. Power off, wait 5 minutes and restart. 2. If it persists, contact the manufacturer. |
| 026 | Inverter Soft Start Failure | Internal inverter failure. | 1. Power off, wait 5 minutes and restart. 2. If it persists, contact the manufacturer. |
| 027 | Inverter Short Circuit | 1. Short circuit at the output terminals. 2. Internal inverter failure. | 1. Power off the unit and check the output terminals for a short circuit. 2. Wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
| 028 | Bus Soft Start Failure | Internal inverter failure. | 1. Power off, wait 5 minutes and restart. 2. If it persists, contact the manufacturer. |
| 029 | Inverter Overtemperature | 1. Heat sink is blocked. 2. Ambient temperature too high. 3. Internal inverter failure. | 1. Turn the inverter off, check the heat sink, and let it cool before restarting. 2. If it persists, contact the manufacturer. |
| 030 | Abnormal DC Current Component | 1. Abnormal local grid voltage. 2. Internal inverter failure. | Restart (5 min). |
| 031 | Abnormal DC Voltage Component | Internal inverter failure. | Restart (5 min). |
| 032 | Abnormal Leakage Current | 1. Not enough insulation between PV panels and ground. 2. Internal inverter failure. | 1. Check all wiring for damage and verify insulation between PV panels and ground. 2. Restart (5 min). 3. If it persists, contact the manufacturer. |
| 033 | Meter Communication Fault | 1. Meter connection is abnormal. 2. Internal inverter failure. | 1. Power off the unit and check the meter connection. 2. If it persists, contact the manufacturer. |
| 034 | Arc Fault | 1. Poor connection between PV panels and the inverter. 2. Internal inverter failure. | 1. Power off the unit and check all connections between the PV array and the inverter. 2. If it persists, contact the manufacturer. |
| 035 | Overtemperature Derating | 1. Heat sink is blocked. 2. Ambient temperature too high. 3. Internal inverter failure. | 1. Turn the inverter off, check the heat sink, and let it cool before restarting. 2. If it persists, contact the manufacturer. |
| 036 | Balancing Bridge Arm Overcurrent | Internal inverter failure. | Restart (5 min). |
Parallel and load (037–044)
| Code | Alarm | Possible cause | Suggestions |
|---|---|---|---|
| 037 | Parallel Master Unit Loss | 1. Abnormal operation of the parallel master unit. 2. Internal inverter failure. | 1. Check whether the parallel master unit is running normally. 2. Check the parallel configuration settings. 3. If both are correct and the fault remains, contact the manufacturer. |
| 038 | Parallel Signal Loss | Internal inverter failure. | 1. Check the parallel configuration settings. 2. If it persists, contact the manufacturer. |
| 039 | Parallel Communication Abnormal | 1. Parallel communication cable connection abnormal. 2. 120-ohm parallel termination resistor not connected. 3. Internal inverter failure. | 1. Power off and check the parallel communication cable connections. 2. Check that the 120-ohm termination resistor is properly connected. 3. If it persists, contact the manufacturer. |
| 040 | Excessive Negative Power | Internal inverter failure. | Restart (5 min). |
| 041 | Parallel Version Mismatch | Inverters in parallel have different firmware versions. | 1. Check that all parallel inverters run the same firmware version. 2. If it persists, contact the manufacturer. |
| 042 | Parallel Setting Error | Incorrect parallel configuration. | 1. Check the parallel configuration settings. 2. If it persists, contact the manufacturer. |
| 043 | Off-grid Overload | 1. Load on the EPS terminal is above the rated power. 2. Load on the EPS terminal has a high inrush current. | 1. Check whether the total load is too high. 2. If it persists, contact the manufacturer. |
| 044 | On-grid Overload | (Manual prints the same causes as 043, referring to the EPS terminal.) | 1. Check whether the total load is too high. 2. If it persists, contact the manufacturer. |
Battery (045–056)
| Code | Alarm | Possible cause | Suggestions |
|---|---|---|---|
| 045 | Battery Overcurrent | 1. Short circuit at the battery output. 2. Internal battery pack failure. | 1. Turn the inverter off and check the battery output terminals for a short circuit. 2. Wait 5 minutes and restart. 3. If it persists, contact the manufacturer. |
| 046 | Battery Overtemperature | 1. Heat sink is blocked. 2. Ambient temperature too high. 3. Internal battery pack failure. | 1. Turn the inverter off, check the heat sink, and let the battery cool before restarting. 2. If it persists, contact the manufacturer. |
| 047 | Battery Low Temperature | 1. Ambient temperature too low. 2. Internal battery pack failure. | 1. Turn the inverter off and check that the ambient temperature is within the normal operating range. 2. If it persists, contact the manufacturer. |
| 048 | Battery Short Circuit | Internal battery pack failure. | Power off the unit and contact the manufacturer for technical support. |
| 049 | Battery Cell Inconsistency | 1. A single cell voltage too high or too low. 2. A single cell temperature too high or too low. 3. Internal battery pack failure. | Power off the unit and contact the manufacturer for technical support. |
| 050 | Battery Undervoltage | 1. Battery self-discharged after long storage. 2. Internal battery pack failure. | 1. Connect PV or grid to use the battery activation function for charging. 2. If the battery cannot be activated, contact the manufacturer. |
| 051 | Battery Overvoltage | 1. Battery overcharged. 2. Poor cell consistency (one cell voltage too high). 3. Internal battery pack failure. | Power off the unit and contact the manufacturer for technical support. |
| 052 | Low Battery State of Health (SOH) | Battery cell performance has degraded. | Contact the manufacturer for technical support. |
| 053 | Battery Bus Overvoltage | 1. Too many PV panels in series. 2. Abnormal grid voltage. 3. Internal battery pack failure. 4. Internal inverter failure. | 1. Turn the inverter off and check that the number of PV panels per string is within specification. 2. Check that the grid voltage is normal. 3. If it persists, contact the manufacturer. |
| 054 | Cycle-by-Cycle Current Limiting Protection | 1. Excessive load. 2. Internal inverter failure. | 1. Turn the inverter off and check whether the total load is too high. 2. Check that the grid voltage is normal. 3. If it persists, contact the manufacturer. |
| 055 | Battery Overload | 1. Battery output power above the rated power. 2. Internal battery pack failure. | 1. Turn the inverter off, wait 5 minutes, connect to the grid and restart. 2. If it persists, contact the manufacturer. |
| 056 | Battery Auxiliary Power Fault | 1. Poor connection between battery pack and inverter. 2. Internal battery pack failure. 3. Internal inverter failure. | 1. Power off the unit and check the connection between the inverter and the battery. 2. If it persists, contact the manufacturer. |
How this table was reconstructed
The Drive text extraction separates code numbers, alarm names, causes and suggestions into blocks on each page. On every page the suggestions appear in the same order as the codes, and each one fits its alarm. For 049–052 the alarm names are scrambled in the extraction. This page assigns them by matching cause and suggestion (e.g. "battery activation function" → Battery Undervoltage). 049 (Cell Inconsistency) and 051 (Battery Overvoltage) share the same suggestion, so their order does not change the action. Check the PDF before quoting those four codes as definitive.
Three-phase wording in a single-phase manual
Code 020 Grid Phase Sequence Fault refers to a three-phase grid, although this manual covers the single-phase MARS I PLUS. The table appears to be shared with MARSTEK's three-phase product. If 020 appears on a single-phase system, escalate to MARSTEK support.
Self-inspection "Abnormal" results
During first-time commissioning the system runs a self-inspection covering PV input, AC, battery, network, electric meter and device. If any item shows "Abnormal", tap it on the display to see possible causes and solutions, and fix it before regular use (manual section 6.1.4).
After a failed OTA update
From manual section 6.2.3:
- Keep the internet connection stable. Do not power off or disconnect the batteries during an upgrade.
- The upgrade may need to run again if the file was corrupted or the connection dropped.
- Some settings can reset to factory defaults. Keep a note of the operating mode and time-of-use schedule so you can set them again.
- If the system is unresponsive for more than about 2 hours, or shows a persistent error after a failed upgrade, contact technical support.
Emergencies (manual section 7.3)
| Situation | What to do |
|---|---|
| Fire | Evacuate immediately and call emergency services. If safe, shut off AC and DC at the main disconnects. Tell firefighters an ESS is on site. Do not use water. |
| Gas leak / explosion risk | Evacuate. Do not operate the system or any switches or plugs. Call emergency services from a safe distance. |
| Overheating, smoke, strange smell | If safe, shut off at the main disconnect switches and contact your installer. Do not keep using it or try to repair it yourself. |
| Flood | Evacuate if instructed. With advance warning, shut down at the main switches. Don't touch the system if water has reached it, and don't restart it until a qualified technician has inspected it. |
Related pages
Sources
- MARS I PLUS user manual V1.4 (Drive): Appendix B Alarm Code Index, sections 6.1.4, 6.2.3, 7.2, 7.3