GeoMax ZBA200 7.4V Replacement Battery ZT80+ 4400mAh

GeoMax ZT80+ / Zoom 20 / Zoom 30 — 7.4V Li-ion Replacement Battery (ZBA200 / ZBA400)

This is a 7.4V, 4400mAh Li-ion battery for the GeoMax ZT80+ total station and compatible GeoMax survey instruments including the Zoom 20, Zoom 30, and Stonex R6+. It replaces OEM part numbers ZBA200 and ZBA400. Capacity figure is drawn from product data — 32.56Wh.

• ZT80+ / Zoom series compatibility: These instruments share the same 7.4V battery platform, connector pinout, and BMS handshake protocol. A single pack type covers the ZT80+, Zoom 20, and Zoom 30 without any adapter or modification.
• Bench tested on actual hardware: We ran the pack through charge and discharge cycles on a test rig monitoring cell balance and BMS trip thresholds. The protection circuit held within spec across simulated sensor-initialisation current spikes — no nuisance cutoffs under normal probe power-up draw.
• First-use calibration on the ZT80+: After fitting a new pack, run a full calibration cycle through the instrument menu before field deployment. The ZT80+ maps battery state during that sequence. Skip it and the instrument will display premature low-battery warnings well before actual charge depletion on the first measurement session.

BMS lockout after the ZT80+ sat unused in a carry case for months

Li-ion cells self-discharge during storage. If the pack drops below roughly 2.5V per cell, the BMS trips an over-discharge lockout and the instrument will not power on — and the charger may show no activity at all. The BMS is protecting the cells from an unsafe charge attempt at that depth. To recover, connect the pack to the OEM charger and leave it for 15–30 minutes; most BMS circuits include a trickle pre-charge mode that will wake the pack once it confirms the cells are above the recovery threshold, typically around 3.0V per cell.

ZT80+ powers on but shuts down mid-measurement during a logging session

Sustained sensor load during active logging draws more current than standby, which causes voltage to sag under load even when the displayed charge percentage looks healthy. If the sag pulls the pack voltage below the BMS low-voltage cutoff threshold, the instrument cuts power to protect the cells — even with apparent charge remaining. This is more common with aged cells that have lost capacity but still read a reasonable state-of-charge at rest. Fitting a fresh pack and running the calibration cycle through the instrument menu resets the voltage-threshold mapping and resolves false cutoffs under load.