EL
ErrorLib
Brands
||
  1. Home
  2. Fronius
  3. Perfect Charging
  4. 25
About·Privacy·Terms

ErrorLib — Industrial Fault Code Library

Disclaimer: ErrorLib is an independent technical reference tool. While we aim for accuracy, always verify with the manufacturer’s official service manuals before performing maintenance on industrial equipment. ErrorLib is not affiliated with the brands listed.

25

Battery Undertemperature (External Sensor)

Fronius · Perfect Charging

What does 25 mean?

The external temperature sensor reports that the battery temperature is too low. Charging certain battery chemistries (e.g., Li-ion) at very low temperatures can cause irreversible damage, such as lithium plating, affecting performance and lifespan.

Common Causes

  • Very low ambient temperature around the battery, causing its internal temperature to drop below safe charging limits.
  • The battery is stored or operated in a cold environment without adequate heating provisions.
  • Inaccurate reading from the external temperature sensor due to poor contact or malfunction.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the ambient temperature surrounding the battery.

  2. 2

    Move the battery to a warmer environment or provide supplemental heating to bring its temperature within the recommended charging range specified by the battery manufacturer.

  3. 3

    Ensure the external temperature sensor is properly attached to the battery surface and functioning correctly.

Browse all codes in this manual (61)
Verified technical data. Last updated: April 2026

Related Faults

101Gateway CAN Connect Timeout102Gateway No Back-end Connection103Gateway Charger/Registration Mismatch
Source: Fronius Perfect Charging
Open Manual (Page 49)Search more codes in this manual