About this replacement
Toshiba ER6V+JAE2P — 3.6V Li-MnO2 Replacement Battery
This is the Toshiba ER6V+JAE2P 3.6V Li-MnO2 cell, rated at 2000mAh (7.2Wh). It fits PLC and industrial controller applications where this part number is specified as the backup memory cell. It keeps SRAM and real-time clock data intact during main power outages.
- PLC backup memory retention: PLCs use a dedicated lithium cell to hold SRAM program data and RTC values when mains power drops. The ER6V+JAE2P sits on a float circuit — the controller draws microamp-level current from the cell only when main power is absent. Voltage must stay above the controller's SRAM retention threshold, typically 2.5–3.0V, to prevent memory loss.
- Bench tested on actual hardware: We ran this cell under simulated PLC backup load conditions. The cell held stable voltage across the discharge curve with no unexpected drop-off, and the protection circuit responded correctly at end-of-life voltage.
- Hot-swap procedure: Always replace this cell with the PLC powered on and in RUN mode. Removing the battery while the controller is off erases SRAM contents immediately. If the PLC was off during the swap, a full program reload from the connected programming device is required before restarting the process.
PLC battery alarm not clearing after a confirmed good installation
Most PLC platforms do not auto-clear a battery alarm once a new cell is seated. The alarm flag is written to a status register and must be reset manually through the programming software — typically via a diagnostic screen or a specific reset command in the ladder logic utility. On many Mitsubishi, Omron, and Keyence controllers, the alarm stays active until the operator acknowledges it in the software, regardless of measured cell voltage. Connect the programming device, navigate to the battery status or system diagnostic menu, and clear the flag there.
New cell reading lower than 3.6V on the PLC's battery monitor
Li-MnO2 cells ship at storage voltage, which can read 3.3–3.5V out of the packaging. This is normal — the cell has not yet been on the PLC's float charge circuit. Within a few hours of installation with the controller powered on, the monitored voltage rises to the rated 3.6V range. If the reading stays below 3.0V after 24 hours on a powered controller, check the battery connector seating and verify the PLC's battery circuit is active before concluding the cell is faulty.