Chcnav i50 XB-2 Replacement Battery 7.4V 2000mAh

Chcnav i50 / M3 / M6 / T3 Series — 7.4V Li-ion Replacement Battery (XB-2)

This is a 7.4V 2000mAh Li-ion replacement battery for the Chcnav i50 GNSS receiver and its related instrument family. It fits the i50, M3, M6, and T3 alongside six additional Chcnav models that share the XB-2 form factor. Capacity figure is 2000mAh (14.8Wh) — taken from the product specification, not estimated.

• i50, M3, M6, T3 cross-compatibility: These models share the same XB-2 battery bay dimensions, 7.4V nominal voltage rail, and connector pinout. The BMS handshake protocol is identical across this instrument family, so one pack covers the full group without firmware conflicts.
• Bench tested on actual hardware: We cycled this pack through power-on, GNSS signal acquisition, and sustained satellite tracking load. The BMS held voltage within the expected window under continuous receiver draw and did not trip on the current spike at antenna module initialisation.
• First-use calibration cycle: After fitting this pack, run a full calibration cycle through the instrument menu before field deployment. The i50 maps battery state during that sequence — skipping it causes premature low-battery warnings during your first survey session even when the pack is fully charged.

BMS lockout after the i50 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 enters a protective sleep state and the instrument will not recognise the battery at all. The charger may also show no activity because the BMS is blocking input current. To recover, place the pack in the Chcnav charger and leave it connected for at least 30 minutes — most chargers apply a low-current pre-charge pulse that nudges the cell voltage above the BMS wake threshold before switching to full charge current.

i50 displaying an inconsistent battery percentage after a pack swap

The i50 tracks remaining capacity against voltage thresholds calibrated to the original cell's discharge curve. A new cell with a slightly different internal resistance will produce voltage readings that sit outside the instrument's stored reference points, causing the percentage indicator to jump or read low at boot. This is a recalibration issue, not a fault with the pack. Run two full charge-discharge cycles through normal field use and the instrument's state-of-charge display will stabilise to an accurate reading.