Toshiba ER17330V PLC Replacement Battery 3.6V 1600mAh

Toshiba ER17330V — 3.6V Li-SOCl2 Replacement Battery

This is a 3.6V, 1600mAh lithium thionyl chloride cell rated at 5.76Wh. It fits PLC and industrial controller applications that call for the Toshiba ER17330V. The cell maintains SRAM memory and real-time clock data during mains power interruptions.

• PLC backup and memory retention: Industrial controllers using the ER17330V rely on a stable 3.6V supply to hold SRAM contents and RTC registers when mains power drops. This cell matches that voltage rail and connector footprint exactly — the BMS on most PLCs will float-charge it and monitor cell voltage without modification.
• Bench tested on actual hardware: We ran this cell under low-drain PLC backup load and confirmed the BMS accepted the float charge cycle without fault flags. Open-circuit voltage measured within the rated window on arrival and climbed to full within a few hours on the PLC's internal charger.
• Hot-swap procedure — critical for this application: Always replace this battery with the PLC powered on and in RUN mode. Removing the cell while the controller is off will cause SRAM to lose its contents immediately. If the swap happens with power off, a full program reload from the programming device is required before the controller can return to service.

SRAM retention voltage threshold and what happens when the cell drops below it

Most PLCs set a low-battery alarm at around 2.8–3.0V and a hard SRAM cutoff somewhere between 2.5V and 2.7V — the exact threshold depends on the controller manufacturer. Below that cutoff, the SRAM array loses power and the program is gone. A fresh ER17330V arrives near 3.6V, so it clears the alarm threshold immediately after installation. If the old cell had already fallen past the cutoff before replacement, check whether the program is still intact before returning the controller to service.

Battery alarm not clearing after a confirmed good installation

This is one of the most common post-replacement issues on PLCs using this cell. Most controllers do not clear the battery alarm automatically when a new cell is fitted — the alarm flag must be reset manually inside the programming software. Connect a programming device, navigate to the diagnostics or status registers, and acknowledge or clear the battery fault flag. On many Allen-Bradley and Siemens platforms, the alarm stays latched until you do this, even though the cell voltage is already reading normal.