Fortuna Clip-On GPS Compatible Battery 3.7V 750mAh

Fortuna Clip-On Bluetooth GPS — 3.7V Li-ion Replacement Battery

This is a 3.7V, 750mAh Li-ion replacement battery for the Fortuna Clip-On Bluetooth GPS receiver. The Clip-On pairs via Bluetooth to smartphones, adding GPS capability to devices that lack dedicated location hardware. When the original cell degrades and the unit stops holding charge, this battery restores full function without replacing the whole accessory.

• Fortuna Clip-On Bluetooth GPS fit: The Clip-On runs a single-cell 3.7V architecture with a compact BMS matched to low-draw Bluetooth and GPS chipsets. This cell matches that voltage rail, physical footprint (53.49 × 33.44 × 6.91mm), and connector orientation so the board sees no interrupt during swap.
• Bench tested on actual hardware: We ran charge-discharge cycles on this cell against the Clip-On's BMS. The protection circuit responded correctly to end-of-charge and low-voltage cutoff events, and no false charge terminations occurred across repeated cycles.
• GPS receiver charging tip: After fitting this cell, complete one full discharge-to-charge cycle before using the unit in active navigation. The Clip-On's fuel gauge IC is calibrated to the old cell's discharge curve — one full cycle resets that reference and gives accurate charge level readings going forward.

Why the Clip-On reports wrong battery percentage after a cell swap

The Clip-On uses a fuel gauge IC that tracks capacity against a stored discharge curve from the original cell. A new cell has a different internal resistance profile, so the IC's coulomb counter starts reading against the wrong reference. The unit may show 100% immediately after a short charge, then drop suddenly. One full discharge from 100% down to auto-shutoff, followed by an uninterrupted charge to full, forces the IC to rebuild its curve against the new cell.

Clip-On unit not powering on after sitting in storage

Li-ion cells self-discharge during storage. If the Clip-On sat unused for several months, the cell voltage may have dropped below 2.5V — the threshold at which the BMS locks out to prevent damage. The unit will not respond to the power button and may show no charging indication initially. Connect it to a 5V USB source and leave it for 20–30 minutes; the BMS recovery circuit will trickle current into the cell until it crosses the 2.9V re-enable threshold, after which normal charging resumes.