About the Felicity FLS48100SG2
The Felicity FLS48100SG2 is a Battery unit. The 21 error codes listed below are the complete fault catalog for this device, compiled from the official Felicity user manual.
FLS48100SG2
Battery21 codes 21 Fault
How to use this page
Each row below shows an error code, its severity, and a brief description. Click any row to expand the full cause and the recommended fix. The severity dot tells you whether the unit will keep operating (warning), derate (fault), or trip offline (critical). For codes that require an authorized service partner, the recommended-fix block says so explicitly.
C01Batterie-Überspannung.Fault
Description
Battery overvoltage. Total pack voltage exceeded the rated upper protection threshold during charging.
Cause
Total battery pack voltage above rated value (Gesamtspannung des Akkupacks über dem Nennwert). Charging continued past the over-voltage protection point.
Recommended fix
Restart the unit. if the error persists, return to repair centre. (Gerät neu starten; bei Wiederauftreten zur Reparatur einsenden.).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC02Batterie-Unterspannung.Fault
Description
Battery undervoltage. Total pack voltage fell below the rated lower protection threshold during discharging.
Cause
Over-discharge protection triggered when total voltage or any cell fell below rated range (Tiefentladeschutz ausgelöst).
Recommended fix
Restart the unit. if the error persists, return to repair centre. (Gerät neu starten; bei Wiederauftreten zur Reparatur einsenden.) Recharge within 18 hours after over-discharge protection.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC03Zell-Überspannung.Fault
Description
Cell overvoltage. Voltage of a single cell exceeded the rated upper protection threshold.
Cause
Single cell voltage reached protection value during charging (Einzelzellenspannung erreichte den Schutzwert).
Recommended fix
Restart the unit. if the error persists, return to repair centre.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC04Zell-Unterspannung.Fault
Description
Cell undervoltage. Voltage of a single cell fell below the rated lower protection threshold.
Cause
Cell voltage below protection value during discharge (Zellenspannung unter dem Schutzwert).
Recommended fix
Restart the unit. if the error persists, return to repair centre.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC05Lade-Überstrom.Fault
Description
Charge overcurrent. Charging current reached the trigger value for 15 seconds; charging overcurrent protection activated and the battery entered fault mode disabling both charge input and discharge output.
Cause
Charging current exceeded trigger value for 15 s (Ladestrom überschritt den Auslösewert für 15 Sekunden). Inverter charge current setting may be too high.
Recommended fix
Fault auto-clears after 1 minute. After 10 occurrences, manual restart is required. Restart the unit; if the error persists, return to repair centre. Set inverter charge current to recommended value (60A x N, max 400A).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC06Entlade-Überstrom.Fault
Description
Discharge overcurrent. Discharging current reached the trigger value for 15 seconds; discharging overcurrent protection activated and the battery entered fault mode disabling both charge input and discharge output.
Cause
Discharging current exceeded trigger value for 15 s (Entladestrom überschritt den Auslösewert für 15 Sekunden). Load or inverter discharge current may be too high.
Recommended fix
Fault auto-clears after 1 minute. After 10 occurrences, manual restart is required. Restart the unit; if the error persists, return to repair centre. Reduce inverter discharge current to recommended value.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC07MOS-Übertemperatur.Fault
Description
MOS (MOSFET) overtemperature. Internal MOSFET temperature exceeded the upper limit.
Cause
1. The inner temperature is over the limitation (Innentemperatur über der Grenze). 2. Ambient temperature may be too high.
Recommended fix
Check whether the ambient temperature is too high. Improve ventilation; allow the unit to cool before restarting. Operating range: -20 deg C to +55 deg C.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC08MOS-Untertemperatur.Fault
Description
MOS (MOSFET) undertemperature. Internal MOSFET temperature is below the lower limit.
Cause
1. The internal temperature is lower than the limit range (Innentemperatur unter dem Grenzbereich). 2. Ambient temperature may be too low.
Recommended fix
Check whether the ambient temperature is too low. Move the battery indoors or warm the environment before restarting. Charging range: 0 deg C to +55 deg C.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC09Zell-Übertemperatur.Fault
Description
Cell overtemperature. Temperature of a battery cell exceeded the upper protection limit.
Cause
Cell temperature above limit (Zellentemperatur über der Schutzgrenze). Possibly excessive ambient temperature, high current, or impaired ventilation.
Recommended fix
Restart the unit. if the error persists, return to repair centre. Verify ambient temperature and ventilation.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC10Zell-Untertemperatur.Fault
Description
Cell undertemperature. Temperature of a battery cell is below the lower protection limit.
Cause
Cell temperature below limit (Zellentemperatur unter der Schutzgrenze). Possibly insufficient ambient temperature.
Recommended fix
Restart the unit. if the error persists, return to repair centre. Charge in an environment within the operating temperature range.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC11Stromsensor abnormal / Anomalie der Strommessung.Fault
Description
Abnormal current sampling. The BMS current measurement returned an out-of-range or invalid reading.
Cause
Internal current sensor or sampling circuit reported abnormal values (Stromsensor liefert anormale Werte).
Recommended fix
Restart the unit. if the error persists, return to repair centre.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC12Anomale Ausgangsimpedanz.Fault
Description
Abnormal output impedance. The output-side impedance measurement is outside the normal range, suggesting a wiring, contact, or load anomaly.
Cause
Output impedance abnormal (Ausgangsimpedanz anormal). Possible loose connection, oxidised terminal, or unusual load.
Recommended fix
Restart the unit. if the error persists, return to repair centre. Inspect output cabling and terminations.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC13Parallelbetrieb fehlgeschlagen.Fault
Description
Parallel failed. The battery could not establish a valid parallel configuration with other units.
Cause
Parallel-installation error (Fehler im Parallelaufbau): single unit reporting parallel state, mis-wired parallel cabling, or incorrect DIP-switch IDs.
Recommended fix
1. Check whether a single unit was incorrectly installed in a parallel system. 2. if the error happens during parallel installation, check wire connections; if connected correctly, finish parallel installation first then restart. 3. if the problem remains, contact your installer. Verify DIP-switch addresses per the DIP code table.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfC14Ausgangsverlust / Ausgang fehlt.Fault
Description
Output loss. No output detected at the battery terminals.
Cause
Circuit breaker open, blown fuse, or internal output failure (Sicherung durchgebrannt, Trennschalter offen oder interner Ausgangsfehler).
Recommended fix
1. Check whether the circuit breaker is closed. 2. Check whether the fuse is normal (the external fuse can be replaced if blown). 3. Restart the unit; if the error persists, return to repair centre.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdfT1Keine Kommunikation mit Wechselrichter.Fault
Description
Unable to communicate with the inverter. Maintenance troubleshooting item (no LCD code).
Cause
The wrong communication cable was used, or the battery DIP-switch settings are incorrect (Falsches Kommunikationskabel verwendet oder DIP-Schalter falsch eingestellt).
Recommended fix
Before connecting the battery to the inverter, set the battery DIP switches correctly according to the DIP-switch table. After setting the DIP switches, restart the battery to activate the DIP, then use the correct communication cable to connect the battery and the inverter.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T2Akku lädt nicht voll.Fault
Description
Battery does not fully charge. Maintenance troubleshooting item (no LCD code).
Cause
The charging voltage set on the inverter is too low (Ladespannung am Wechselrichter zu niedrig).
Recommended fix
Set the charging voltage on the inverter according to the recommended value in the battery manual (Max. charging voltage 57.6V; Float 57.6V; Cut-off 48V).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T3Ungenaue SOC-Anzeige.Fault
Description
Inaccurate SOC display. Maintenance troubleshooting item (no LCD code).
Cause
The battery's SOC has not been calibrated (SOC nicht kalibriert).
Recommended fix
The SOC will automatically calibrate after one full charge cycle. First, discharge the battery to 0%, then charge it to 100%. Fully charge the battery at least once per month for accurate SOC.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T4Hoher Lade-/Entladestrom verursacht Ausgangsabschaltung.Fault
Description
High current charging and discharging causes output cutoff. Maintenance troubleshooting item (no LCD code).
Cause
The charging and discharging current set on the inverter is too high (Lade- und Entladestrom am Wechselrichter zu hoch).
Recommended fix
Set the charging and discharging current on the inverter according to the recommended values in the battery manual (60A x N, max 400A).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T5Akkuausgang unterbrochen wegen hohen Stroms.Fault
Description
Battery output is interrupted due to high current during charging and discharging. Maintenance troubleshooting item (no LCD code).
Cause
The charging and discharging current settings on the inverter are too high.
Recommended fix
Set the charging and discharging current on the inverter according to the recommendations in the battery manual.
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T6Akkudaten am Wechselrichter fehlen oder falsch (Parallelbetrieb).Fault
Description
When multiple batteries are connected in parallel, battery data on the inverter is missing or incorrect. Maintenance troubleshooting item (no LCD code).
Cause
The parallel connection of the batteries is not set up correctly (Parallelverbindung nicht korrekt konfiguriert).
Recommended fix
1. Check the communication cables between the batteries. 2. Check whether the battery DIP switches are set in the correct sequence (per the DIP code table).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27T7Akku zeigt Laden, aber SOC ändert sich nicht.Fault
Description
The battery indicates it is charging, but the SOC does not change. Maintenance troubleshooting item (no LCD code).
Cause
The ambient temperature is too low, preventing the battery from charging (Umgebungstemperatur zu niedrig, Laden blockiert).
Recommended fix
Charge the battery in an indoor environment that meets the operating temperature range specified in the manual (charging range 0 deg C to +55 deg C).
Source:
Benutzerhandbuch - Felicity FLS48100SG2.pdf · page 27Step-by-step troubleshooting checklist
- 1.Note the exact code and timing
Write down the exact code shown on the display, what the unit was doing when it appeared (charging, discharging, idle, grid-tied), and any LEDs or audible alarms. The same code can have different fixes depending on context.
- 2.Check the recommended fix on this page
Find the code in the list below and read the cause + recommended fix. Most warning-level codes can be cleared by following the listed action — usually reducing load, checking wiring, or restarting the unit.
- 3.Verify the source manual page
Each code shows the source manual filename and page number. Open that exact page in the official manual to verify model-specific notes (firmware version, parallel-config notes, regional variants) before acting.
- 4.Disconnect AC, DC, and battery before opening
If a fix requires opening the enclosure or accessing terminals, disconnect AC input, DC PV, and battery in that order. Wait at least 60 seconds for capacitors to discharge before touching any conductors.
- 5.Escalate critical codes to authorized service
Critical codes (short-circuit, IGBT failure, BMS hardware error) should not be cleared by end users. Note the code, model number, and source manual page, then contact an authorized service partner.
Common questions about FLS48100SG2 error codes
- Where can I find the official Felicity FLS48100SG2 error code manual?
- Each code on this page lists the official source manual filename and page number at the bottom. The manuals are published by Felicity on their website; we compile the codes here so you can search across all of them at once instead of opening each PDF.
- Is the FLS48100SG2 the same as other Felicity models?
- Some Felicity units share firmware across a family of variants — the same fault codes apply to multiple model numbers. Look at the "also covers" chips below the title to see which other model numbers this page applies to.
- What's the most critical code on a Felicity FLS48100SG2?
- Critical-severity codes (red dot) are the ones that trip the unit offline immediately — typically short-circuit, IGBT, or BMS hardware failures. These are listed first when you filter by severity. Do not bypass them; they indicate a hardware or safety condition that requires service.
Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.