GT102 GPS Tracker Replacement Battery 3.7V 900mAh Li-ion

GPS Tracker GT102 / TK102 — 3.7V Li-ion Replacement Battery

This 3.7V 900mAh (3.33Wh) Li-ion cell replaces the original battery in the GPS Tracker GT102 and TK102 compact tracking devices. Both models use the same battery footprint — 46.20 x 34.14 x 5.68mm — and the same 3.7V single-cell architecture. Fit the replacement when the original cell can no longer hold charge through a full tracking session.

• GT102 and TK102 compatibility: Both trackers run off an identical single Li-ion cell at 3.7V nominal with the same physical connector and board layout. The BMS on each unit handles charge cutoff at 4.2V and discharge protection at approximately 3.0V — this cell works within both those limits.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the GT102 platform. The onboard BMS accepted charge current without tripping, and cutoff engaged cleanly at both the high and low voltage thresholds with no thermal event.
• First-cycle recalibration on the GT102: After fitting this cell, run one complete discharge-to-charge cycle with the device active before relying on the battery indicator. The GT102's fuel gauge IC calibrates its coulomb counter against the new cell's discharge curve during that first full cycle.

Why the GT102 shows incorrect battery percentage after a cell swap

The GT102 uses a fuel gauge IC that tracks charge by counting coulombs against a stored discharge curve from the original cell. When you fit a new cell, that stored curve no longer matches the new cell's actual voltage-to-capacity profile. The result is a percentage reading that drifts — sometimes reading full when the cell is partially depleted. One complete discharge and charge cycle forces the IC to relearn the curve and corrects the displayed percentage.

GT102 powering off with percentage still showing above zero

This happens when the cell voltage drops below the BMS cutoff threshold under load before the displayed percentage reaches 0%. On a degraded or deeply discharged cell, the resting voltage may read acceptable, but under the GPS radio and cellular transmission load, it sags past 3.0V and the BMS shuts the device down. A new cell restores the capacity buffer between resting voltage and loaded voltage. After fitting this replacement, charge fully to 4.2V before first active use.