About this replacement
INAX IN-AM-90 — 3V Li-MnO2 Replacement Battery (A-4035)
This is a 3V lithium-manganese dioxide battery rated at 4800mAh, built to the A-4035 specification for the INAX IN-AM-90 automatic flush valve. It powers the infrared sensor and solenoid that trigger automatic flushing when a user is detected. The cell dimensions are 46.30 × 34.00 × 17.10mm — measure your existing cell before ordering if you are unsure.
- IN-AM-90 sensor and solenoid draw: The flush valve runs a continuous low-current sensor circuit, then pulls a brief high-current spike through the solenoid on each flush cycle. The 3V Li-MnO2 chemistry holds a flat discharge curve across both states, which keeps the sensor logic stable as the cell ages.
- Bench tested on actual hardware: We cycled this cell through repeated solenoid activation pulses and confirmed the BMS did not trip under normal flush-cycle loads. Voltage held above the solenoid minimum activation threshold throughout the test run.
- Post-install sensor reset: After fitting this battery, wave your hand slowly across the sensor face three times. This triggers the unit's self-test flush sequence and confirms the new cell voltage is accepted and the sensor is live.
Flusher activating randomly after a new battery is fitted
Random activation after a battery swap usually means the sensor is responding to residual capacitor charge or an uncalibrated detection window — not a faulty cell. The IN-AM-90 sensor resets its baseline presence-detection threshold on power-up. If the unit was powered on while someone was already standing in front of it, the sensor may log that position as the ambient baseline and then trigger on movement away from it. Remove the battery, wait 30 seconds, refit it, and step clear of the sensor zone before it powers back up. This forces a clean baseline calibration against an empty space.
Self-test flush does not complete after battery installation
If the self-test wave sequence produces no flush or only a partial valve movement, the most common cause is insufficient voltage to fully drive the solenoid open. Li-MnO2 cells ship at full charge, so a low reading on a new cell points to an incorrect cell type being fitted or a polarity error in the battery compartment. Check the positive terminal alignment against the marking in the housing. A correctly seated A-4035 cell should read 3.0V at the terminals before installation — test with a multimeter if activation still fails after reseating.