Hi-Target BT10 ZTS-120 Replacement Battery 7.4V 2600mAh

Hi-Target ZTS-120 Total Station — 7.4V Li-ion Replacement Battery (BT10)

This is a 7.4V, 2600mAh Li-ion replacement for the Hi-Target BT10 battery pack. It fits the ZTS-120, ZTS-120R, and related total station variants used in land surveying and construction layout. Voltage and cell chemistry match the original spec exactly.

• ZTS-120 and ZTS-120R compatibility: These models share the same 7.4V battery rail, BT10 connector footprint, and BMS handshake protocol. Swapping between variants on-site is straightforward — the instrument reads the pack identically across the series.
• Bench tested on actual hardware: We cycled this pack through full charge-discharge sequences and monitored BMS cutoff response under simulated sensor initialisation loads. The protection circuit held within the expected voltage window without nuisance trips during angle-measurement and tracking sequences.
• Post-install calibration cycle: After fitting this pack, run a full calibration cycle through the ZTS-120 instrument menu before heading to site. The instrument maps battery state during that routine. Skipping it causes premature low-battery warnings during your first measurement session, even with a fully charged pack.

BMS lockout on the ZTS-120 after the pack sat unused in a carry case

Li-ion cells self-discharge slowly in storage. If a BT10-type pack drops below approximately 2.5V per cell, the BMS trips into a protective sleep state and the instrument will not power on — even when connected to a charger. The charger sees the pack as absent or faulty because the BMS is blocking the charge path. A slow pre-charge or trickle mode on a compatible Li-ion charger is usually enough to push the cell voltage back above the BMS recovery threshold, at which point normal charging resumes.

Angle readings resetting mid-session while battery indicator still shows charge

This happens when sustained EDM or motorised drive load pulls the pack voltage below the ZTS-120's internal reset threshold — even briefly. The display may still show a battery percentage because the voltage-threshold indicator hasn't fully recalculated yet. The root cause is cell voltage sag under load, not remaining capacity. Check resting voltage with a multimeter: a healthy pack at partial charge should read above 7.2V at rest. If it reads below that after a short session, the cells have degraded and the pack needs replacement.