Typhoon MyGuide 3500 Go Replacement Battery 3.7V 1250mAh

Typhoon MyGuide 3500 Go — 3.7V Li-ion Replacement Battery

This 3.7V 1250mAh Li-ion cell replaces the original battery in the Typhoon MyGuide 3500 Go portable GPS navigator. It fits directly into the battery compartment and restores full power to the device. Capacity figure is drawn from the product data — 1250mAh at 3.7V, equating to 4.63Wh.

• MyGuide 3500 Go fit: The 3500 Go runs a single-cell 3.7V Li-ion configuration. This cell matches that voltage rail and physical footprint — 50.00 × 36.60 × 6.60mm — so the connector seats correctly and the protection circuit communicates with the device charge controller without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The onboard BMS held cutoff at the correct low-voltage threshold and accepted a full charge without thermal event. Charge acceptance and cutoff behaviour matched what the MyGuide 3500 Go expects from its original cell.
• Cold-start initialisation after fitting: After fitting this cell, power the unit on outdoors with a clear sky view and leave it stationary. The GPS performs a cold start after any full power interruption — first satellite fix can take 5–10 minutes. Subsequent warm starts drop back under a minute once almanac data is cached.

GPS accuracy reduced at low battery on the MyGuide 3500 Go

The MyGuide 3500 Go reduces GPS receiver sensitivity as the cell voltage drops toward the low-voltage cutoff threshold. This is a deliberate power-saving behaviour, not a fault with the battery or antenna. Position accuracy can degrade noticeably — sometimes by tens of metres — before the device shows a low battery indicator. Keeping the cell above 3.6V during active navigation maintains full receiver performance.

MyGuide 3500 Go shuts off without warning before the battery indicator empties

After a battery swap, the fuel gauge in the MyGuide 3500 Go is uncalibrated to the new cell. The device reads the displayed charge level from a software estimate, not a direct coulomb count, and that estimate drifts against the actual cell state. The BMS hard cutoff triggers at the cell's real low-voltage floor — around 3.0V — while the screen may still show bars remaining. Run two or three full charge-to-cutoff cycles to let the estimate converge with actual cell capacity.