EPEVER Solar Charge Controller: “Battery red slow flash — over-temp”
warning RV solar charge controller error codes
What it means
The battery indicator slowly flashing red signals a battery temperature fault: with a temperature sensor connected, the controller has detected the battery too hot (above ~65 C) or, for lithium, too cold (below the low-temperature threshold), and has stopped charging/discharging.
Most likely causes
- Battery overheating — high ambient temperature, poor ventilation, or heavy charge/discharge most likely
- Lithium battery below its low-temperature charging threshold (cold weather) common
- Faulty or poorly mounted remote temperature sensor giving a bad reading less common
Safe checks you can do yourself
- Feel/measure the battery temperature and check the battery compartment ventilation
- For lithium banks in cold conditions, confirm the temperature is below the low-temperature protection threshold
- Verify the remote temperature sensor is properly attached to the battery and its cable is intact
How to reset / clear Battery red slow flash — over-temp
- Remove the cause: improve cooling/ventilation for an overheating battery, or warm a cold lithium battery
- The controller resumes automatically once battery temperature returns to the safe range (overheat clears below ~55 C)
When to call a technician
If the battery runs hot under normal conditions, or the fault persists with a correctly mounted sensor and normal battery temperature, have the battery and sensor checked.
Applies to
EPEVER Triron N series · EPEVER Tracer-AN series · EPEVER Tracer-BN/BP series
FAQ
What does EPEVER Solar Charge Controller code "Battery red slow flash — over-temp" mean?
The battery indicator slowly flashing red signals a battery temperature fault: with a temperature sensor connected, the controller has detected the battery too hot (above ~65 C) or, for lithium, too cold (below the low-temperature threshold), and has stopped charging/discharging.
How do I reset EPEVER Solar Charge Controller Battery red slow flash — over-temp?
Remove the cause: improve cooling/ventilation for an overheating battery, or warm a cold lithium battery The controller resumes automatically once battery temperature returns to the safe range (overheat clears below ~55 C)
What is the most common cause of Battery red slow flash — over-temp on a EPEVER Solar Charge Controller?
The most likely cause is battery overheating — high ambient temperature, poor ventilation, or heavy charge/discharge.
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Sources
- EPEVER TRIRON N Series Modular MPPT Solar Charge Controller User Manual — TRIRON-SMS-EL-V1.2, Section 4.1 — Battery LED Red Slowly Flashing (1Hz) = Battery Overheating / Low temperature; Section 6.1 Protection (battery stops above 65 C, resumes below 55 C) (EPEVER (Huizhou EPEVER Technology Co., Ltd.))
- MPPT Solar Charge Controller User Manual, Tracer-AN series — Tracer-AN-Manual-EN-V2.6, Section 4.1 protections — Battery overheating: stops above 65 C, resumes below 55 C; Lithium low-temperature protection (LTPT default 0 C) (EPEVER (Huizhou EPEVER Technology Co., Ltd.))
Note: Battery temperature protection only works when the optional remote temperature sensor is connected; without it, the controller cannot detect battery temperature. With lead-acid batteries there is no low-temperature protection.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.