FLIR C2 Thermal Camera Replacement Battery 3.7V 1000mAh

Flir C2 / C3 — 3.7V Li-Polymer Replacement Battery (T199369)

This 3.7V, 1000mAh lithium-polymer battery replaces the original T199369 cell in the Flir C2 and C3 compact thermal cameras. Both models use the same battery bay, connector, and BMS communication protocol. Dimensions are 51.60 × 34.00 × 5.40mm — a direct physical match to the factory cell.

• C2 and C3 shared platform: Flir built the C2 and C3 on the same hardware platform — identical battery bay dimensions, the same 3.7V supply rail, and a shared BMS handshake. One replacement cell covers both models without any modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a C2 unit. The BMS accepted the cell without fault flags, and charge termination triggered correctly at full capacity.
• Post-swap warm-up requirement: After fitting this battery, power the camera on and wait 60 seconds before taking measurements. The C2 and C3 thermal detectors need the internal electronics to reach a stable temperature before the baseline calibration is valid — skipping this step produces inaccurate readings, not a faulty battery.

Why the C2 shuts down mid-inspection on a new battery

The C2 runs two high-draw subsystems simultaneously: the thermal detector's resistive heating element and the LCD display backlight. Under peak combined load, the BMS reads a momentary voltage sag and trips the protection circuit before the battery indicator reaches the low threshold. This is a BMS protection event, not a capacity failure. It occurs most often in cold environments where internal resistance rises and voltage sag deepens under the same load. If shutdowns are frequent, check that the battery contacts in the bay are clean — oxidised contacts increase resistance and make the sag worse.

Thermal accuracy dropping before the battery indicator shows low

The C2's thermal detector is voltage-sensitive — measurement accuracy begins to drift before the battery reaches the conventional low-battery threshold. As the cell discharges toward 3.4V under load, the detector's reference voltage becomes unstable and temperature readings shift by several degrees. The battery gauge on-screen is calibrated for display and sensor power combined, so it lags behind the actual detector voltage. If readings look off before the low-battery warning appears, check cell voltage directly — below 3.45V under load, swap the battery before continuing measurements.