CHC X91 GNSS Receiver Replacement Battery 7.4V 3400mAh

CHC X91 / X93 / X900 GNSS Receiver — 7.4V Li-ion Replacement Battery (1906110059)

This 7.4V 3400mAh Li-ion battery replaces the OEM pack in CHC X91, X93, and X900 GNSS receivers. It fits the battery bay directly and uses the same cell configuration as the factory pack. Capacity figures are taken from our product data, not estimated from field reports.

• X91, X93, and X900 compatibility: These three receivers share the same battery bay geometry, connector pinout, and BMS communication protocol. The 7.4V voltage rail and cell arrangement are identical across the series, so one part number covers all three units without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on an X91 unit. The BMS handshake completed on first insertion, the receiver read state-of-charge correctly, and the protection circuit triggered cleanly at the low-voltage cutoff threshold without causing a hard fault in the receiver firmware.
• Post-install calibration on the X91/X93/X900: After fitting a new pack, run a full calibration cycle through the receiver's system menu before heading to site. The X91 series maps battery state during calibration. Skip this step and the receiver's low-battery warning fires early on the first field session, even with a fully charged pack.

BMS lockout after the X91 sat unused in a carry case for months

Li-ion cells self-discharge during storage. If the X91 pack drops below approximately 2.5V per cell during an extended layoff, the BMS enters a protective sleep state and blocks charge current entirely. The charger shows no activity, and the receiver will not power on. To recover the pack, connect it to the OEM charger and leave it for up to 30 minutes — most BMS circuits include a trickle pre-charge path that slowly raises cell voltage back above the recovery threshold before switching to normal charge mode.

X91 shuts down mid-session while satellite lock is active

This is not the same as a depleted battery — it is a voltage sag event. When the X91's RF front-end and satellite tracking engine are both running under full load, instantaneous current draw spikes. If the cell voltage dips below the BMS cutoff threshold during that spike, the protection circuit trips and the receiver powers off abruptly, taking any unsaved observation data with it. The fix is to check cell voltage before deployment: if resting voltage reads below 7.0V on a multimeter, charge the pack fully to 8.4V before heading to site, even if the onscreen indicator still shows partial charge.