TSC1 29518 Li-ion Replacement Battery 7.4V 3400mAh

TSC1 29518 / 38403 / 46607 — 7.4V Li-ion Replacement Battery

This 7.4V 3400mAh Li-ion pack replaces the original battery in TSC1 survey and field data collection instruments. It covers OEM part numbers 29518, 38403, 46607, 52030, C8872A, and EI-D-LI1. Slot it into your TSC1 unit, complete an instrument calibration cycle, and get back to site work.

• Multi-OEM part number coverage: TSC1 issued several part numbers across firmware and hardware revisions — 29518, 38403, 46607, 52030, C8872A, and EI-D-LI1 — but the physical pack, connector pinout, and BMS handshake stayed consistent across all of them. One replacement covers the full range.
• Bench tested on actual hardware: We ran this pack through probe initialisation cycles and sustained sensor-load draws. The BMS held stable at rated voltage under continuous logging loads and did not trip on the current spike that occurs when external probes power up.
• Calibration cycle before first field deployment: After installing this pack, run a full calibration sequence through the instrument menu before heading to site. The TSC1 maps battery state during that cycle — skip it and the instrument will flag premature low-battery warnings during your first measurement session, even with a full charge.

BMS lockout after a TSC1 pack sits unused in a carry case for months

Li-ion cells self-discharge at roughly 1–3% per month. If a TSC1 instrument sits in a case for an extended period, the pack can drop below 2.5V per cell — the threshold where most BMS circuits hard-lock to prevent cell damage. At that point the instrument will not power on and the charger may show no activity. Connect the charger and leave it for at least 60–90 minutes before attempting to power on; most BMS circuits include a trickle-recovery mode that will slowly bring the cell voltage back above the re-initialisation threshold of approximately 3.0V per cell. If the charger still shows no response after two hours, the cells have likely gone below recoverable voltage.

TSC1 resetting or losing logged data mid-session under sustained sensor load

Sustained sensor operation draws more current than idle or GPS-only modes, and a degraded or partially discharged cell can sag below the instrument's minimum voltage rail before the fuel gauge registers low. The result is an unexpected reset or data loss with the display still showing a partial charge. This is a voltage-sag failure, not a capacity failure — the cell can't maintain voltage under load even if it holds charge at rest. Check the pack's resting voltage with a multimeter after a full charge; it should read 8.3–8.4V. Anything below 8.0V at rest signals a cell that will sag under load and should be replaced.