About this replacement
Sanyo CR8.L / CR8.LHC — 3V Li-MnO2 Replacement Battery (CR17450)
This is a 3V, 2600mAh lithium manganese dioxide cell that replaces the Sanyo CR17450 in CR8.L and CR8.LHC PLC controllers. It maintains SRAM program memory and the real-time clock when primary power is cut. Replace it before the existing cell drops below the SRAM retention threshold — a dead cell means a blank controller.
- CR8.L and CR8.LHC compatibility: Both models use the same CR17450 footprint, voltage rail, and connector orientation. The backup circuit draws from this cell continuously during standby, so chemistry and self-discharge rate matter as much as physical fit.
- Bench tested on actual hardware: We verified open-circuit voltage at 3.0V and confirmed stable load response under the low-current SRAM retention draw typical of this controller family. No voltage sag or BMS anomalies observed at that draw level.
- Hot-swap procedure for CR8.L: Always replace this cell with the PLC powered on and in RUN mode. Removing the battery while the controller is off will erase SRAM — the program and RTC data are gone the moment voltage drops. If you powered the PLC off before swapping, a full program reload from your programming device is required.
PLC losing program memory after battery swap
SRAM in the CR8.L has no capacitor backup — it relies entirely on continuous voltage from the CR17450. The moment cell voltage drops below the retention threshold, typically around 2.0V, stored data is lost. This happens in seconds if the battery is removed while the controller is off. If you swapped the cell correctly with the PLC powered on and still see a blank program, the existing cell had already failed and SRAM had been unprotected before you started — reload the program from your last backup.
Battery alarm not clearing after a confirmed good installation
The CR8.L does not auto-clear a battery fault alarm after the cell is replaced. The alarm flag is written to a status register and stays set until you manually reset it through your programming software. Connect to the controller, navigate to the diagnostics or status section, and clear the battery alarm flag explicitly. If the alarm returns within minutes of clearing, check that the new cell is seated fully and making clean contact — a loose cell reads as low voltage to the monitoring circuit.