GeoMax Stonex R6 Replacement Battery 7.4V 5600mAh ZBA200

GeoMax Stonex R6 / Zoom 20 / Zoom 35 — 7.4V Li-ion Replacement Battery (ZBA200 / ZBA400)

This 7.4V 5600mAh Li-ion battery replaces the ZBA200 and ZBA400 packs used in GeoMax GNSS receivers and total stations. It fits the Stonex R6, Zoom 20, Zoom 30, and Zoom 35. Capacity is 41.44Wh — sourced to match OEM cell specification.

• Stonex R6, Zoom 20, Zoom 30, Zoom 35 — shared battery platform: GeoMax standardised the ZBA200/ZBA400 form factor across both its GNSS and total station lines. The connector pinout, BMS handshake protocol, and 7.4V nominal voltage rail are identical across all four models listed. One pack fits the whole range without modification.
• Bench tested on actual hardware: We ran this pack through RTK lock cycles and satellite acquisition sequences. The BMS held cutoff thresholds within spec under sustained multi-constellation tracking load, and charge acceptance was consistent across repeated cycles without triggering protection flags.
• Post-installation calibration — run it before your first field session: After fitting this battery, navigate to the instrument's battery calibration or power management menu and run a full discharge-charge cycle through the device. The Stonex R6 maps battery state during this process. Skipping it causes the low-battery warning to trigger early on the first real session, interrupting data collection mid-survey.

BMS cutoff during satellite acquisition on the Stonex R6

When the Stonex R6 initialises its multi-constellation tracking engine, the modem and RF front-end draw a short current spike that can trip the BMS on a cold or partially discharged pack. This is not a faulty battery — it is a protection threshold response. Charge the pack to full before powering on in cold conditions, since low temperature increases internal resistance and amplifies the apparent current spike. If the device cuts off at power-on and won't restart, leave it on charge for 15 minutes before retrying.

Zoom 20 / Zoom 30 showing "0%" or erratic charge percentage after fitting a new pack

The Zoom series uses a voltage-threshold method to estimate charge state, not a dedicated fuel gauge. A new pack sits at open-circuit voltage, which doesn't always map cleanly to the instrument's stored discharge curve from the old cell. The display recalibrates over the first full discharge-charge cycle — until then, percentage readings will jump or read low. Run the pack down to auto-shutoff once, charge fully, and the indicator will stabilise to accurate readings from that point forward.