HESP series hybrid inverters (single-phase 4-12 kW and three-phase 8-12 kW)
SRNE 31 error code
Battery capacity low alarm 2 (BatCapacityLow2): BMS reports SOC below the second, deeper low-capacity threshold (5 percent).
Likely causes
- Battery nearly empty after a long outage
- Charging failures from PV or grid
- BMS SOC drift or an unbalanced pack
- Load left running overnight
Checks to run, in order
- 1Read SOC and pack voltage from the BMS
- 2Check whether the pack is balanced and whether SOC is plausible for the voltage
- 3Confirm charging sources are available
- 4Review the overnight load
Fixes
- Charge immediately and reduce the load
- Recharge fully so the BMS can recalibrate SOC
- Investigate any recurring overnight discharge
When to escalate
If SOC falls to this level while the battery voltage stays high, ask the distributor to check BMS SOC calibration before the pack is relied on for backup.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does SRNE 31 mean?
Battery capacity low alarm 2 (BatCapacityLow2): BMS reports SOC below the second, deeper low-capacity threshold (5 percent).
How do I fix SRNE 31?
Charge immediately and reduce the load Recharge fully so the BMS can recalibrate SOC Investigate any recurring overnight discharge
When should I escalate SRNE 31?
If SOC falls to this level while the battery voltage stays high, ask the distributor to check BMS SOC calibration before the pack is relied on for backup.
Can I reset SRNE 31 myself?
Only after isolating the AC and DC sides and running the checks above. If SRNE 31 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show SRNE 31?
SRNE 31 is documented for HESP series hybrid inverters (single-phase 4-12 kW and three-phase 8-12 kW). Confirm the code on your own unit's display or manual before ordering parts.
More SRNE error codes
- SRNE 01Battery undervoltage alarm: the battery voltage has fallen below the [Batt. Under volt. alarm] value under Battery Setup, and the alarm does not by itself stop the output.
- SRNE 02Battery discharge average current overcurrent, detected by software (BatOverCurrSw); the inverter limits or stops discharge.
- SRNE 03Battery not connected (BatOpen): the inverter cannot see a battery on the DC side and stops the output.
- SRNE 04Battery undervoltage stop-discharge (BatLowEod): the battery has reached the low-voltage cut-off and the inverter has stopped discharging.
- SRNE 05Battery overcurrent detected by hardware protection (BatOverCurrHw); the inverter shuts the output down.
- SRNE 06Charging overvoltage protection (BatOverVolt): battery voltage rose above the over-voltage cut-off and charging was stopped.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
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