Typhoon Myguide 4328 GPS Replacement Battery M10A 3.7V

Typhoon Myguide 4328 — 3.7V Li-ion Replacement Battery (M10A)

This 3.7V 1100mAh Li-ion cell replaces the original battery in the Typhoon Myguide 4328, Myguide 4328 BT, and Myguide 4328 sat nav. It matches the OEM M10A and CM-2 part numbers and sits within the same 53.90 × 34.70 × 5.20mm footprint. Capacity is 4.07Wh — identical to the factory specification.

• Myguide 4328 platform fit: The 4328, 4328 BT, and 4328 sat nav variants share the same battery bay dimensions, connector pinout, and 3.7V supply rail. One cell covers all three — no adapter or modification required.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Myguide 4328 platform. The BMS held a stable charge curve to 4.2V and cut off cleanly at the low-voltage threshold without triggering false shutdowns.
• Cold-start satellite acquisition after fitting: After any full power interruption, the Myguide 4328 performs a cold start. Take the unit outdoors immediately after fitting and power it on — first satellite fix typically takes 5 to 10 minutes. Subsequent warm starts drop to under a minute once ephemeris data is cached.

GPS accuracy dropping at low battery on the Myguide 4328

When the cell voltage falls below roughly 3.5V, some GPS receivers reduce signal-processing power to extend remaining charge. On the Myguide 4328 this can show as position drift or slower route recalculation before the low-battery indicator appears. It is not a unit fault — it is a deliberate power-saving behaviour at the receiver level. Keeping the cell above 3.6V during active navigation maintains full receiver sensitivity.

Myguide 4328 shutting off without low-battery warning

This happens when the fuel gauge is uncalibrated against the new cell's discharge curve. The unit's voltage-threshold logic was last calibrated to the worn original battery, which had a steeper voltage drop near end of charge. The new cell holds a flatter discharge curve, so the software does not see a gradual warning zone — it hits the hardware cutoff at around 3.0V abruptly. Run two full charge-discharge cycles to let the gauge recalibrate against the new cell's profile.