Leica GEB87 TCA1100 Replacement Battery 12V 2100mAh

Leica TCA1100 / TPS1000 Series — 12V Ni-MH Replacement Battery (GEB87 / GEB187)

This 12V, 2100mAh Ni-MH battery replaces the GEB87 and GEB187 cells used in Leica total stations. It fits the TCA1100, TCA1700, TCA1800, and TPS1000 series instruments. The pack slots into the original battery bay and connects to the instrument's power management circuit without modification.

• TCA and TPS series compatibility: The TCA1100, TCA1700, TCA1800, and TPS1000 share the same 12V battery bay format and connector pinout. The BMS handshake protocol and voltage rail are identical across these models, so one pack covers all of them.
• Bench tested on actual hardware: We ran this pack through the TCA1100 power-on sequence, EDM initialisation, and sustained angle-logging cycles. The BMS held voltage within the instrument's accepted threshold throughout, and the pack passed full charge acceptance without triggering protection cutoff.
• Post-installation calibration on the TCA1100: After fitting a new pack, run a full instrument calibration cycle through the TCA menu before heading into the field. The TCA1100 maps battery state during that calibration sequence — skipping it causes the instrument to flag premature low-battery warnings on the first measurement session.

BMS lockout after a TCA1100 pack sits unused in a carry case for months

Ni-MH cells self-discharge during storage at roughly 1–2% per day without a load. After several months in a case, the pack voltage can drop below the BMS recovery threshold — typically around 9V for a 12V Ni-MH pack — and the protection circuit locks out both charge and discharge. The instrument won't power on and the charger shows no activity. To recover the pack, use a Ni-MH compatible charger with a reconditioning or trickle-charge mode to bring cells back above 10V before attempting a full charge cycle.

TCA1100 shuts off mid-measurement with the battery showing partial charge

This happens when cell capacity has faded enough that voltage sags sharply under the combined EDM and servo load, even though the resting voltage looked acceptable before the session. The instrument's voltage comparator triggers a shutdown before the indicator reaches zero. It's not a display error — the cells no longer sustain the current draw at mid-state-of-charge. Check resting voltage with a multimeter after a full charge: a healthy 12V Ni-MH pack should read at or above 13.2V; anything below 12.0V at rest points to cell degradation requiring replacement.