About this replacement
Flir E33 / E40 / E50 Series — 3.7V Li-ion Replacement Battery (T197752)
This 3.7V, 6800mAh Li-ion battery replaces the original pack in Flir E33, E40, E40bx, and E50 thermal imaging cameras. It matches OEM part numbers T197752, T198487, T198553, T199363, and T199363ACC. Physical dimensions are 78.00 × 40.20 × 21.60mm — confirm these against your existing pack before ordering.
- E33 / E40 / E50 platform fit: These models share the same battery bay dimensions, connector pinout, and BMS communication protocol. One battery cell format serves the full range, which is why the same OEM part numbers appear across all five compatible models.
- Bench tested on actual hardware: We ran this cell under combined display and thermal detector load — the scenario that triggers most BMS protection trips. The BMS held stable across the full discharge curve and did not cut out on simulated high-draw inspection cycles.
- Post-swap power-on procedure: After fitting a new battery, allow the camera 60 seconds at power-on before taking any measurements. The uncooled microbolometer detector needs the internal electronics to stabilise before it can establish an accurate thermal baseline — skipping this step produces readings that drift in the first minute.
Why the E33 shuts down mid-inspection on a new battery
The E33 runs two continuous power draws simultaneously: the LCD display and the detector heating element that keeps the microbolometer at operating temperature. Together these can spike current demand well above what a degraded or counterfeit cell can sustain. Even a new battery with a poorly tuned BMS will interpret that combined surge as an overcurrent event and trip the protection circuit. This cell's BMS is calibrated with enough headroom to handle the combined display-plus-detector load without tripping on start-up or during sustained use.
Thermal readings drifting before the battery indicator shows low
Microbolometer accuracy in the E-series cameras is voltage-sensitive. As cell voltage drops below approximately 3.5V, the detector's reference voltage becomes unstable and temperature readings begin to drift before the on-screen battery indicator flags a low charge state. The camera's fuel gauge reads a capacity estimate, not instantaneous cell voltage, so it lags behind real-world cell condition. If readings drift or emissivity corrections look inconsistent near the end of a session, treat that as a low-voltage signal and recharge before the indicator catches up.