Anern AN-SCI-EVO OEM series (SMS 2 kVA/12 V, 4.2 kW/24 V, 10.2 kVA/48 V hybrid units)
SMS Sunmate Solar 04 error code
Battery under-voltage: the bank has discharged below the inverter's low-voltage cutoff. The same number is also used as a low-battery warning (beep once per second).
Likely causes
- Bank discharged after a long outage
- Battery bank undersized for the load
- Loose or undersized DC cables causing voltage drop under load
- Weak or dead cell in the bank
- Low-voltage cutoff set too high for the load
Checks to run, in order
- 1Measure the battery voltage at the terminals and again at the inverter DC input while loaded
- 2Check DC cable size, lugs and terminal torque
- 3Load-test the bank or check each block with a hydrometer/conductance tester
- 4Confirm the low-voltage cutoff setting suits the battery type
Fixes
- Recharge the bank from grid or PV and retest
- Tighten or replace undersized DC cables and lugs
- Replace weak or dead batteries in the bank
When to escalate
If the voltage reads normal on a rested bank but code 04 returns immediately under light load, the BMS or DC input board needs distributor service.
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 SMS Sunmate Solar 04 mean?
Battery under-voltage: the bank has discharged below the inverter's low-voltage cutoff. The same number is also used as a low-battery warning (beep once per second).
How do I fix SMS Sunmate Solar 04?
Recharge the bank from grid or PV and retest Tighten or replace undersized DC cables and lugs Replace weak or dead batteries in the bank
When should I escalate SMS Sunmate Solar 04?
If the voltage reads normal on a rested bank but code 04 returns immediately under light load, the BMS or DC input board needs distributor service.
Can I reset SMS Sunmate Solar 04 myself?
Only after isolating the AC and DC sides and running the checks above. If SMS Sunmate Solar 04 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show SMS Sunmate Solar 04?
SMS Sunmate Solar 04 is documented for Anern AN-SCI-EVO OEM series (SMS 2 kVA/12 V, 4.2 kW/24 V, 10.2 kVA/48 V hybrid units). Confirm the code on your own unit's display or manual before ordering parts.
More SMS Sunmate Solar error codes
- SMS Sunmate Solar 01Fan failure: the cooling fan is blocked or not turning. The same code appears as a warning when the fan is blocked while the inverter is running.
- SMS Sunmate Solar 02Over-temperature: internal component temperature above 100 °C, or converter temperature above 120 °C.
- SMS Sunmate Solar 03Battery over-voltage: the battery bank is charged above the inverter's high-voltage limit. The same number is also used as a warning (beep once per second) when the battery is overcharged.
- SMS Sunmate Solar 05Output short circuit: a short is detected on the AC output.
- SMS Sunmate Solar 06Abnormal output voltage: the inverter output is above 260 V AC (the manual groups 06 and 58 as output voltage outside the 190–260 V AC band).
- SMS Sunmate Solar 07Overload timeout: the inverter has been loaded above 110% of its rating and the overload timer has expired, so the output is switched off.
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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