Lithium battery BMS
Felicity 04 error code
Low cell voltage / over-discharge protection.
Likely causes
- Bank discharged below protection threshold
- Cell imbalance
- Charger not delivering expected current
Checks to run, in order
- 1Check state of charge and cell voltages in the BMS app
- 2Confirm charge source is working
- 3Review load profile
Fixes
- Charge the bank fully and allow cell balancing
- Reduce overnight load
- Raise low-voltage cutoff where appropriate
When to escalate
Repeated over-discharge or a cell that will not balance needs a warranty assessment.
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 Felicity 04 mean?
Low cell voltage / over-discharge protection.
How do I fix Felicity 04?
Charge the bank fully and allow cell balancing Reduce overnight load Raise low-voltage cutoff where appropriate
When should I escalate Felicity 04?
Repeated over-discharge or a cell that will not balance needs a warranty assessment.
More Felicity error codes
Search the full error-code database in the troubleshooting tool.
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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