Troubleshooting
To determine the status of the battery protection system, use the Sunsynk app or refer to the LED/LCD indicators as described in the Operation section. For protection mode activation, refer to the solutions below. If the issue persists after following the recommended solution, contact Sunsynk service.
| Fault / Protection Event | Threshold / Condition | Possible Cause | Solution |
|---|---|---|---|
| Information collection fails | Sampling circuit fault | Fault in collection line or BMS circuit | Replace the collection line. If the fault persists, replace the battery and contact Sunsynk service. |
| Under voltage — cell | Cell voltage < 2.8 V | Cell deeply discharged; battery ageing | Disconnect the battery. Do not attempt to charge a cell below 2.0 V. Replace the battery and contact Sunsynk service. |
| Under voltage — pack | Pack voltage < 44.8 V | Pack deeply discharged | As above. Charge immediately if the pack voltage is still above 44.8 V. |
| Over voltage — cell | Cell voltage > 3.65 V | Inverter overcharging; incorrect charge settings | Check inverter connection and settings. Verify sampling circuit is normal. Contact service if the fault persists. |
| Over voltage — pack | Pack voltage > 58.4 V | Overcharge from inverter | Check inverter settings and cable connections. |
| Charge over temperature | Charge temp > 55°C | High charge current; high ambient temperature; blocked ventilation | Reduce charge current. Check ambient temperature and ventilation. Check for battery ageing. |
| Charge under temperature | Charge temp < 0°C | Low ambient temperature | Move battery to a warmer environment before charging. Do not charge below 0°C. |
| Discharge over temperature | Discharge temp > 55°C | High discharge current; high ambient temperature | Reduce discharge load. Check ambient temperature and ventilation. |
| Discharge under temperature | Discharge temp < −20°C | Extremely low ambient temperature | Move battery to a warmer environment. Do not discharge below −20°C. |
| Short circuit protection | Short circuit detected | External short circuit; damaged wiring | Inspect all cable connections and terminals. If the battery has a high self-discharge rate, replace it. Contact Sunsynk service. |
| High charge current | Charge current exceeds limit | Incorrect inverter charge settings | Verify and correct inverter charge current settings. Do not exceed 160 A. |
| High discharge current | Discharge current exceeds limit | Excessive connected load | Reduce load. Do not exceed 230 A continuous discharge. |
| MOS adhesion | Internal MOSFET fault | Internal protection circuit fault | Contact Sunsynk service. Do not attempt to repair. |
| Cell electrochemical imbalance | Cell voltage imbalance | Cell ageing; long-term imbalance | Check individual cell voltages. If any cell is below 2.0 V after external correction, replace the battery. |
| PCS communication fails | No communication with inverter | Loose or incorrect communication cable; wrong PCS settings | Check communication cable connections. Verify that PCS is set to CAN 500 kbps or RS485 9600 bps as applicable. |
| Inter-module communication fails | No communication between batteries in parallel chain | Damaged or incorrect communication cable between units | Check all IN/OUT port connections along the parallel chain. Replace faulty cable. |
Notice
Once you know the protection mode has been activated, refer to the above solutions. If you are unable to resolve the issue, contact Sunsynk service using the contact information provided on the back cover of this manual.