CNC battery A02B-0200-K102 for Fanuc 16i, 18i, 21i & Le Blonde 77

The CNC battery A02B-0200-K102 (often identified by the cell part number A98L-0031-0012) is a specialised 3-volt lithium backup battery. It is the life insurance for the control data of your Fanuc i-series (16i, 18i, 21i) as well as compatible machines such as the Le Blonde 77.

This battery secures the SRAM memory of the CNC controller. It stores critical data such as CNC parameters, tool offsets, workpiece zero points and the PLC program (ladder). A failure of this battery leads to the immediate loss of this data ("System Parity Error"), which results in a complete machine standstill and a costly restoration of the parameters.

Highlights at a glance

• Original specification: Developed as an exact replacement for the Fanuc order number A02B-0200-K102. The actual cell often bears the identification A98L-0031-0012.
• High reliability: Uses lithium poly-carbon monofluoride (BR series) chemistry (mostly Panasonic BR-2/3A), which is specially designed for long-term applications with low discharge.
• Voltage: 3.0 Volt.
• Capacity: 1,200 mAh (High Capacity for size 2/3 A).
• Ready to plug in: Delivered as assembly with cable and the specific black 2-pin connector (JAE type), which fits exactly to the Fanuc board.
• Long life: Typical durability of 3 to 7 years in operation (depending on the operating time of the machine) and up to 10 years shelf life.

Areas of application

This battery is compatible with a wide range of Fanuc controllers and servo systems, especially:

• Fanuc Series 16i / 160i / 162i
• Fanuc Series 18i / 180i / 182i
• Fanuc Series 21i / 210i / 212i
• Fanuc Power Mate iD / iH
• Le Blonde 77 CNC (if equipped with Fanuc control)
• Location: Mostly behind the LCD display or in a special battery compartment on the CNC unit.

Installation & Safety Advice

• The most important rule: Always replace the CNC buffer battery ALWAYS with the machine powered on (Power ON).
  • Reason: If you switch off the machine and remove the old battery, the capacitor on the board will only buffer for about 20-30 minutes. If the replacement takes longer or the capacitor is old, the memory will be erased. With the machine powered on, the power supply provides the memory and the change is safe.
• Note the alarm: Replace the battery immediately if the display shows the message "BAT" is flashing or the alarm "Battery Low" (often alarm code APC 300 series or system alarm) appears. Do not wait until the next maintenance interval.
• Position: The battery is often located on the rear of the display unit (MDI/CRT Unit) under a small yellow or black cover.

Features

FAQs for A02B-0200-K102

Is this the battery for the drives (servos) or the controller?

The A02B-0200-K102 (A98L-0031-0012) is primarily the battery for the CNC controller (memory backup). For the servo amplifier (absolute axis position) often other batteries are used (e.g. large mono D cells or the A98L-0031-0025 in the black box). Check exactly which alarm message you have ("System Battery" vs. "APC Battery").

My battery has a brown connector, this one has a black one. Will this fit?

Caution. The connector (JAE) has a mechanical coding (nose).

• A98L-0031-0012: Black connector (for i-series controllers).
• A98L-0031-0026 / -0028: Often brown or cream-coloured connector (for Beta drivers or older systems). Compare the nose on the connector exactly with your old part. Forcing it will damage the connection on the expensive CNC board.

Can I use a standard CR123A battery?

No. Although they look similar, photo batteries (CR123A) have different dimensions and do not have solder tags/connectors. DIY solutions with adhesive tape in vibration-rich CNC machines risk loose contacts and data loss.