Fluke VT04 Replacement Battery 3.7V 3400mAh Li-ion

Fluke VT04 Visual IR Thermometer — 3.7V Li-ion Replacement Battery (FLK-VT04)

This 3.7V Li-ion battery carries 3400mAh (12.58Wh) and fits the Fluke VT04 and VT04A Visual IR Thermometer. The VT04 is a compact thermal imaging camera used for electrical and mechanical fault-finding in the field. Swap this in when the original cell degrades and the camera stops holding a charge through a full inspection.

• VT04 and VT04A compatibility: Both models share the same battery bay, connector pin-out, and BMS handshake protocol. The OEM part numbers FLK-VT04 and 4375741 both reference this cell, so either stamped label on your original battery confirms this replacement fits.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on VT04 hardware. The BMS communicated correctly with the camera's charge controller — no false low-battery flags and no mid-session protection trips under the combined thermal detector and display load.
• Warm-up requirement before scanning: After powering on with a fresh battery, let the camera sit idle for 60 seconds before taking readings. The thermal detector needs the internal electronics to reach a stable temperature for accurate baseline calibration — skipping this step produces offset readings, not a fault with the battery.

Thermal camera shutting down mid-inspection on a new battery

The VT04 draws current from two sources simultaneously — the LCD display and the resistive heating element that keeps the thermal detector at operating temperature. On a degraded cell, that combined draw triggers the BMS over-current protection and shuts the camera down even when the charge indicator still shows partial charge. A fresh cell with a healthy internal resistance handles this load without tripping protection. If the new battery causes the same shutdowns, check that the battery contacts in the bay are clean and making full contact — even slight oxidation raises resistance enough to trigger cutoff under peak draw.

Thermal accuracy degrading before the battery indicator shows low

The VT04's thermal detector is sensitive to supply voltage — when the cell drops below approximately 3.5V under load, the detector's reference circuit loses accuracy before the camera's fuel gauge registers a low-battery warning. This means temperature readings can drift by several degrees while the display still shows adequate charge. It is not a camera fault. Replacing an aged cell that sags under load restores the stable voltage the detector needs and brings readings back within the rated ±4°C accuracy band.