FANUC Series 0i-F / 0i-F Plus warning DS0307: APC ALARM: BATTERY LOW 1
DS0307 (APC ALARM: BATTERY LOW 1) on a FANUC 0i-F means the absolute position detector battery voltage has dropped to a level at which replacement is required. The position data is still held, and FANUC says to replace the battery with the machine turned on so the absolute position is kept.
Diagnose this with AI
Try Free CNC Alarm Diagnostic Upload a keypad photo, the fault history or a parameter export from your FANUC Series 0i-F / 0i-F Plus. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Any time the control is on; often first seen at power-up
Likely causes and checks
1Battery at end of life
- Points to it
- Alarm after a long service period; DGN 3019 shows the detector concerned.
- Check
- Replace the batteries with the machine (CNC) powered on and an emergency stop applied, within a week of the alarm, by trained personnel; FANUC refers to the alpha i servo motor maintenance manual for the detailed procedure.
2Wrong or poor-quality replacement battery
- Points to it
- Alarm returns soon after a recent replacement.
- Check
- Check the battery type and voltage against FANUC’s specification for the amplifier battery case.
3Battery connection resistance
- Points to it
- Battery measures good out of circuit but alarm persists on one axis.
- Check
- Inspect the battery holder and cable to that amplifier.
Telling it apart
- DS0306 means the voltage was too low to hold data (or first power-up) and the reference position must be set again.
- DS0308 (BATTERY LOW 2) records that the voltage was low in the past, including while powered off, even if it is now acceptable.
- The memory backup battery for the CNC (programs, offsets, parameters) is a separate battery with its own low-battery alarm.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| DGN 3019 (diagnosis) | Detector battery exhaustion | ABP, INP and EXP bits show which detector battery is low. |
Evidence to collect
- DGN 3019 bits
- Battery voltage and age
- Which amplifiers share the battery
Work on fuel trains, burners, pressure vessels and electrical equipment must be done by qualified personnel following the manufacturer’s documentation and local codes. Never bypass a safety device or interlock.