About this replacement
Mitac Mio Moov 400 Series — 3.7V Li-ion Replacement Battery (338937010172)
This 3.7V 750mAh Li-ion cell replaces the original battery in the Mitac Mio Moov 400, Moov 405, MIO 4190, and M1100 portable GPS navigators. It matches the OEM part numbers 338937010172 and T300-3. Fit the cell when the unit no longer holds charge through a typical drive or shuts off before the indicator reaches empty.
- Moov 400 and 405 platform: These models share the same battery bay dimensions (50 × 37 × 6mm), connector pinout, and 3.7V charge rail. The BMS on each unit reads the same charge profile, so no firmware workaround is needed when swapping cells across this group.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Mio Moov 400 unit. The BMS accepted charge without fault flags, balanced correctly at 4.2V, and held cutoff voltage at the expected 3.0V threshold.
- Cold-start satellite acquisition after swap: After fitting this cell, power the GPS on outdoors before driving. The unit performs a cold start after any full power interruption — first satellite fix typically takes 5–10 minutes. Subsequent warm starts run under a minute once the almanac is cached.
GPS accuracy reduced at low battery on the Mio Moov 400
The Mio Moov 400 scales back receiver sensitivity as cell voltage drops toward the 3.0V cutoff. This is a firmware-level power saving measure — the GPS chip draws less current by narrowing its signal search window. The result is degraded position accuracy and slower route recalculation on low charge. Keep the unit above 50% charge during active navigation to avoid this behaviour.
Unit shuts off without warning before the battery indicator hits empty
After a full power removal, the Mio Moov 400 loses its calibrated voltage-to-percentage mapping. The fuel gauge defaults to a generic discharge curve that does not match the actual cell. The unit then hits the BMS cutoff voltage — 3.0V — before the on-screen indicator reaches one bar. Run two full charge and discharge cycles after fitting the new cell to let the device recalibrate its threshold readings.