Tosight TSEL-110 Replacement Battery 7.2V 1200mAh

Tosight TSEL-110 / TSEL-2000 — 7.2V Li-ion Replacement Battery (NL374964H-2S)

This 7.2V, 1200mAh Li-ion pack replaces the OEM NL374964H-2S battery in Tosight TSEL-110 and TSEL-2000 survey and measurement instruments. It matches the original voltage rail and physical form factor exactly. Capacity is 1200mAh (8.64Wh), matching the stock specification.

• TSEL-110 and TSEL-2000 compatibility: Both models run the same 7.2V bus, share the NL374964H-2S form factor, and use identical BMS handshake protocols — so one pack covers both instruments without modification.
• Bench tested on actual hardware: We cycled this pack through probe initialisation sequences, which pull a short current spike at power-up. The BMS held the load without tripping, and the instrument accepted the pack without error flags.
• Post-install calibration step: After fitting this pack, run a full calibration cycle through the instrument menu before heading to the field. The TSEL maps battery state during calibration — skip it and the instrument will throw premature low-battery warnings on your first measurement session.

BMS lockout after the TSEL-110 sat unused in a carry case for months

Li-ion cells self-discharge during storage. If the pack drops below approximately 2.5V per cell, the BMS enters a protective lockout state and the instrument will not recognise it at all. Placing a locked-out pack on the charger often does nothing because the charger handshake also fails below that threshold. To recover, apply a compatible charger that supports a slow pre-charge or trickle mode — this brings cell voltage back above the BMS wake-up floor, typically around 2.9V per cell, at which point normal charging resumes.

Instrument shuts down mid-measurement despite showing adequate charge

This happens when sustained sensor load pulls the pack voltage below the instrument's cutoff threshold — not because the pack is empty, but because internal resistance causes a momentary voltage sag under load. An ageing OEM cell exaggerates this sag even at 50% state of charge. A fresh pack with lower internal resistance holds the voltage rail steady through the same load. If the new pack still triggers shutdowns, check that you ran the post-install calibration cycle — the instrument needs to map the new cell's voltage curve before it can track state of charge accurately.