FLIR i3 Thermal Camera Replacement Battery 3.7V 3400mAh 1950986

Flir i3 / i5 / i7 / IRC40 — 3.7V Li-ion Replacement Battery (1950986)

This 3.7V, 3400mAh Li-ion battery replaces part number 1950986 in the Flir i3, i5, i7, and IRC40 thermal imaging cameras. These are compact handheld units used for building diagnostics, electrical panel inspections, and mechanical fault finding. Voltage and capacity match the original specification exactly.

• i3, i5, i7, and IRC40 compatibility: All four models share the same battery form factor, 3.7V nominal rail, and connector pinout. The BMS handshake protocol is identical across this camera family, so the same cell works in any of them without modification.
• Bench tested on actual hardware: We ran this battery through full charge and discharge cycles on an i7 unit. The BMS held steady under the combined draw of the LCD display and the resistive detector heating element — no false low-voltage cutoffs during normal operation.
• Post-swap warm-up requirement: After fitting a new battery and powering on, allow at least 60 seconds before taking measurements. The thermal detector needs the internal electronics to reach a stable temperature before it can establish an accurate baseline calibration — readings taken in the first minute can drift noticeably.

Thermal camera shutting down mid-inspection on a new battery

The Flir i-series draws current from two sources simultaneously — the display backlight and the detector's heating element. On a cold start, both ramp up at the same time, creating a short current spike that can trigger the BMS over-current protection if the cell's internal resistance is too high. A degraded or deeply discharged original battery fails here first. This replacement uses cells rated for the combined peak draw, so the BMS doesn't see a voltage sag large enough to trip the cutoff.

Image accuracy degrading before the battery indicator shows low

The Flir i-series thermal detector is voltage-sensitive — it needs the supply rail to stay above approximately 3.4V to maintain calibrated accuracy. A worn battery can sag below this threshold under detector load while the fuel gauge still reads mid-charge, because the gauge measures resting voltage, not loaded voltage. The result is temperature readings that drift or blur before any low-battery warning appears. If measurements become inconsistent partway through a job, check the battery voltage under load — replace if it drops below 3.4V during active scanning.