About this replacement
TSI AeroTrak 9306 Series — 7.4V Li-ion Replacement Battery (700032)
This is a 7.4V 4400mAh Li-ion replacement battery for the TSI AeroTrak 9306 portable particle counter and related models including the EP-03750, 8532, and AeroTrak 9036-01. It uses OEM part number 700032 and matches the original pack's cell voltage, connector, and BMS communication spec. The 32.56Wh capacity keeps the instrument running through extended cleanroom surveys and contamination assessments.
- AeroTrak 9306 and compatible models: These instruments share a common power rail at 7.4V nominal and use the same dock connector with BMS handshake. The pack must pass the instrument's battery authentication check on boot or the device refuses to operate — this replacement meets that handshake requirement.
- Bench tested on actual hardware: We ran this pack through the AeroTrak 9306 power-on sequence, including the sensor initialisation burst and sustained laser-diode draw during active particle counting. The BMS held stable through the startup current spike and did not trip the protection circuit under normal operating load.
- Pre-deployment calibration step: After installing this battery, run a full calibration cycle through the instrument menu before taking it to the field. The AeroTrak maps battery state during calibration — skipping this step causes the low-battery warning to trigger too early on the first measurement session, even with a full charge.
BMS lockout after the AeroTrak 9306 sat unused in a carry case for months
Li-ion cells self-discharge slowly in storage. If the pack drops below approximately 2.5V per cell, the BMS trips its deep-discharge protection and locks the pack out entirely — the instrument won't power on and the charger shows no activity. This isn't a dead battery; it's a protection state. To recover, apply a compatible charger for 15–30 minutes at a low rate before attempting to power the instrument. If cell voltage has not dropped below the hard cutoff floor, the BMS will re-initialise and normal charging resumes.
AeroTrak 9306 shuts down mid-count with the battery indicator showing charge remaining
This happens when the laser diode and particle sensor draw a sustained load that causes momentary voltage sag below the instrument's shutdown threshold — even though the displayed percentage looked fine. An aged cell loses internal resistance headroom, so voltage collapses briefly under load even if resting voltage reads normal. A new pack with healthy cells holds voltage under sustained draw and avoids this dropout. After fitting the replacement, verify resting voltage reads at or above 8.0V before the first field session.