UniStrong G1 GNSS Receiver Compatible Battery 3.7V 1600mAh

UniStrong G1 Series — 3.7V Li-ion Replacement Battery (UG-1LH)

This is a 3.7V 1600mAh Li-ion replacement battery carrying OEM part number UG-1LH. It fits the UniStrong G1 GNSS receiver and the G120, G120BD, and G130BD variants used in field surveying and mapping. Voltage and capacity match the original pack specification exactly.

• G1 and G120 series compatibility: These models share the same 3.7V power rail, physical footprint, and BMS handshake protocol. The connector orientation and cell contact layout are identical across the G1, G120, G120BD, and G130BD, so the same pack serves all four without modification.
• Bench tested on actual hardware: We cycled this pack through a full GNSS acquisition sequence on the G1. The BMS held stable under the combined draw of satellite lock, IMU polling, and data logging. No undervoltage cutoff events were recorded during sustained field-load simulation.
• Post-install calibration on the G1: After fitting this pack, run a full calibration cycle from the G1 instrument menu before field deployment. The receiver maps battery state during calibration — skipping this causes premature low-battery warnings to appear during the first measurement session, even with a fully charged cell.

BMS cutoff during satellite acquisition on the G1

When the G1 initialises its GNSS module and locks onto satellites, current draw spikes sharply for two to four seconds. A degraded or deeply discharged pack can't sustain this spike, and the BMS trips the protection circuit to prevent cell damage. This causes an immediate shutdown that looks like a power fault rather than a battery issue. Charge the replacement pack to at least 3.9V before first use — this puts the cell above the BMS's surge-trip threshold.

G1 display showing incorrect charge percentage after swap

The G1's charge indicator is calibrated against the original cell's discharge curve. A new pack will read incorrectly — often jumping between percentages — until the receiver maps the new cell's voltage profile. This is a display calibration issue, not a cell fault. Run one full discharge-to-shutdown followed by a complete charge cycle, then perform the instrument calibration sequence. The indicator stabilises within one to two cycles.