Toshiba JZSP-BA01 PLC Replacement Battery 3.6V 1000mAh

Toshiba JZSP-BA01 — 3.6V Li-MnO2 Replacement Battery

This is a 3.6V 1000mAh lithium manganese dioxide cell that replaces the Toshiba JZSP-BA01 and JZSP-BA01-1 backup batteries. It maintains SRAM program memory and real-time clock (RTC) function during mains power loss in Toshiba PLC systems. Physically, the cell measures 25.50 × 14.50 × 14.50mm and drops directly into the same battery holder.

• Toshiba PLC backup application: The JZSP-BA01 sits on a float circuit inside the controller. During a mains outage, it holds the SRAM voltage rail at the threshold required to retain the stored program and RTC data. Without it, both are wiped the moment external power drops.
• Bench tested on actual hardware: We confirmed the cell holds a stable open-circuit voltage at or above 3.6V and verified the Li-MnO2 discharge profile is flat enough to stay above the typical PLC SRAM retention threshold across the expected service life.
• Hot-swap procedure — no exceptions: Always replace this battery with the PLC powered on and in RUN mode. Pulling the cell while the controller is powered off drains SRAM instantly. If that happens, the full program must be reloaded from a connected programming device before the controller will run.

PLC losing program memory after battery swap

This happens when the old cell is removed while the PLC is powered off or in STOP mode. SRAM has no backup voltage source during that window, so all stored data is lost the moment the old cell leaves the holder. Even a brief gap between removing the old cell and inserting the new one can be enough on some controllers. To avoid this, keep the PLC energised and in RUN mode throughout the swap — the capacitive hold on most Toshiba controllers lasts only a few seconds.

Battery alarm not clearing after a confirmed good installation

The PLC battery alarm flag is set in firmware and does not reset automatically when a new cell is detected. After fitting the replacement, the alarm must be cleared manually through the programming software — typically via the system diagnostics or battery status register. On Toshiba controllers, failing to clear this flag can leave the HMI or SCADA showing a persistent fault even though the new cell is seated and reading correct voltage. Connect a programming device, navigate to the battery alarm register, and reset it explicitly before closing out the maintenance record.