HESP series hybrid inverters (single-phase 4-12 kW and three-phase 8-12 kW)
SRNE 01 error code
Battery 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.
Likely causes
- Battery discharged below the configured undervoltage alarm threshold
- No charging from PV or grid (night, grid outage, AC charge disabled)
- Load draining the bank faster than the available charge
- Voltage drop on undersized or loose battery cables
Checks to run, in order
- 1Measure battery voltage at the inverter DC terminals and compare it with the value in Battery Setup > Battery Discharge > Batt. Under volt. alarm
- 2Compare the inverter reading with the BMS/app reading to rule out a sensing error
- 3Confirm PV power and AC charging are actually flowing (charge LED, app power flow)
- 4Check the battery breaker, fuse and terminal torque
Fixes
- Charge the battery until it is above the low-voltage recovery value; the IESP manual specifies 2 V above the alarm value
- Reduce or stagger the load until the bank recovers
- Correct undersized or loose battery cabling
- Only adjust the alarm threshold inside the battery manufacturer's limits
When to escalate
If the alarm appears on a charged bank, or the inverter reading disagrees with a calibrated meter, have the distributor check the DC voltage sensing circuit.
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 01 mean?
Battery 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.
How do I fix SRNE 01?
Charge the battery until it is above the low-voltage recovery value; the IESP manual specifies 2 V above the alarm value Reduce or stagger the load until the bank recovers Correct undersized or loose battery cabling Only adjust the alarm threshold inside the battery manufacturer's limits
When should I escalate SRNE 01?
If the alarm appears on a charged bank, or the inverter reading disagrees with a calibrated meter, have the distributor check the DC voltage sensing circuit.
Can I reset SRNE 01 myself?
Only after isolating the AC and DC sides and running the checks above. If SRNE 01 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show SRNE 01?
SRNE 01 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 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.
- SRNE 07Internal DC bus overvoltage detected by hardware protection (BusOverVoltHw); the inverter stops the output.
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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