Bay West 200-145 4.5V Automatic Flusher Replacement Battery

Bay West 750TFWR / 800TFWR Series — 4.5V Alkaline Replacement Battery (200-145)

This is a 4.5V alkaline replacement battery (Part No 200-145) for Bay West automatic sensor flush valves. It fits the 750TFWR, 800 Wave Dispenser, 800TFT, and 800TFWR models. Capacity is 51000mAh (229.5Wh), matching the voltage and current draw requirements of the motion sensor and solenoid valve assembly.

• 750TFWR and 800-series flush valves: These models share the same 4.5V battery compartment, solenoid coil voltage rating, and PIR sensor supply rail — one battery spec covers all four fit models listed.
• Bench tested on actual hardware: We cycled the solenoid repeatedly under load to confirm the BMS accepted the cells without undervoltage lockout — activation was consistent across every test flush.
• Post-install sensor reset: After fitting this battery, wave a hand slowly in front of the sensor three times. This triggers the unit's self-test flush sequence and confirms the sensor has re-initialised correctly with the new power source.

Flusher not activating after battery replacement

The solenoid valve in the 750TFWR needs a clean 4.5V supply to generate enough magnetic force to open the water inlet. If the installed cells drop below roughly 3.6V under load — common with partially discharged or incorrect cell types — the solenoid coil won't pull in. Check polarity first: the battery compartment contacts are easy to reverse on the 800-series housing. If polarity is correct and the unit still won't fire, measure open-circuit voltage across the contacts — anything below 4.2V means the cells are underspec for this valve.

Flusher triggering on its own after a fresh battery install

Random activation after a battery swap usually means the PIR sensor is still running on its previous calibration baseline, which was set against a lower supply voltage. A fresh 4.5V supply briefly raises sensor sensitivity above the detection threshold, causing phantom trips. Power-cycle the unit completely — remove the battery, wait 30 seconds, then refit and allow two minutes for the sensor to recalibrate against ambient IR levels in the room. Phantom flushes should stop after that settling window.