Navcom PASSY 7.4V Replacement Battery 2000mAh Li-ion

Navcom PASSY / RT-3010S / SF-3040 / Ultra RTK — 7.4V Li-ion Replacement Battery

This 7.4V 2000mAh Li-ion battery replaces the original pack in Navcom PASSY, RT-3010S, SF-3040, and Ultra RTK surveying receivers. These units are used for land surveying and geospatial data collection in the field. The battery dimensions are 70.60 × 38.60 × 20.54mm — verify your pack measures the same before ordering.

• PASSY / RT-3010S / SF-3040 / Ultra RTK platform fit: These four Navcom receivers share the same battery bay geometry, connector pin-out, and BMS communication protocol — one pack covers all four units in the same series.
• Bench tested on actual hardware: We ran charge and discharge cycles through a PASSY unit, confirmed BMS handshake, and verified the protection circuit responded correctly to overvoltage and undervoltage cutoff thresholds during both satellite acquisition and active logging.
• First-use calibration on Navcom receivers: After installing, run a full calibration cycle through the instrument menu before field deployment. The receiver maps battery state during that process — skip it and the low-battery warning will trigger early on the first session, even with a full charge.

BMS cutoff when the GNSS module initialises at power-on

At startup, the GNSS module in these Navcom receivers draws a short but sharp current spike as it initialises the RF front-end and locks to satellite signals. If the battery's state of charge is borderline or the cell voltage has sagged after storage, that spike can push the BMS into overcurrent cutoff. The unit shuts down instantly — it does not log an error. Charge the pack to full before first use and allow the receiver to complete its startup sequence while connected to the charger if the issue repeats.

Receiver shows inconsistent battery percentage every time it reboots

This happens when a new cell's discharge curve does not yet match the voltage-to-percentage table the receiver loaded from the old pack. The indicator reads voltage, translates it to a percentage estimate, and gets it wrong until the cell has been through several full cycles. Run two to three full charge and discharge cycles through normal field use. By the third cycle the receiver's estimate will track actual capacity accurately — the display should stabilise around 4.18–4.20V per cell at a genuine 100%.