About this replacement
Testo 876 — 3.7V Li-ion Replacement Battery (0515 0116)
This 3.7V 5200mAh Li-ion battery replaces the OEM pack in the Testo 876 thermal imaging camera. It fits the 876 directly, using OEM part numbers 0515 0116 and 0554 8852. Capacity is sourced from the product data — 5200mAh / 19.24Wh.
- Testo 876 platform fit: The 876 uses a single-cell 3.7V Li-ion pack with a dedicated BMS handshake line. The connector pinout and protection circuit must match the OEM spec exactly — the camera's firmware reads pack status through that interface and will refuse to boot on a mismatch.
- Bench tested on actual hardware: We ran this pack through the 876's boot sequence and sustained infrared capture load. The BMS held stable through both the detector initialisation current spike at power-up and the continuous imaging draw that follows.
- First-use calibration on the 876: After installing this pack, run a full calibration cycle through the instrument menu before heading to site. The 876 maps battery state during calibration — skipping this step causes premature low-battery warnings to appear during your first measurement session in the field.
Testo 876 shutting down mid-scan during extended thermal surveys
The 876's IR detector draws a sustained load during continuous imaging — higher than standby, and higher again when the unit is writing images to the SD card simultaneously. An aged or degraded cell cannot hold the voltage rail stable under that combined draw. The BMS interprets the resulting voltage sag as a low-cell event and cuts power to protect the pack. Replacing the cell resolves this — a fresh 5200mAh pack holds well above the 3.0V cutoff threshold under sustained field load.
Testo 876 not recognising a new pack after the camera sat unused for months
If a pack discharges below roughly 2.5V during storage, the BMS enters a low-voltage sleep state and the 876 will not acknowledge the battery at all — the screen stays blank or shows a battery error on the first press of the power button. Connect the camera to its Testo mains charger for at least 15 minutes before attempting to power on. This trickle-charges the cell back above the BMS recovery threshold, typically around 2.8–3.0V, and re-initialises the protection circuit.