Magellan RoadMate 9250 Replacement Battery 3.7V 1000mAh

Magellan RoadMate 9250 Series — 3.7V Li-ion Replacement Battery (338937010158)

This 3.7V 1000mAh Li-ion cell replaces the original battery in the Magellan RoadMate 9250, 9250T-LM, and 9250T-LMB portable GPS navigators. It shares the same OEM part number 338937010158 across all three variants. Dimensions are 50.36 x 36.44 x 5.56mm — confirming a direct physical fit before ordering saves time.

• RoadMate 9250 variant coverage: The 9250, 9250T-LM, and 9250T-LMB share the same battery bay dimensions, connector pinout, and voltage rail, so one cell covers all three. The T-LM and T-LMB add lifetime map and Bluetooth features but make no change to the battery specification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the RoadMate 9250 platform. The onboard BMS accepted the cell without fault flags, charge termination triggered cleanly at full capacity, and the low-voltage cutoff held at the correct threshold without premature shutdown.
• First satellite fix after fitting: After any full power interruption, the GPS receiver loses its ephemeris data and performs a cold start. Power the unit on outdoors with a clear sky view and allow 5–10 minutes for the first satellite fix. Subsequent warm starts take under a minute once almanac data is cached.

GPS accuracy dropping at low battery on the RoadMate 9250

When cell voltage falls below roughly 3.5V, some GPS units reduce receiver sensitivity to protect remaining power. On the RoadMate 9250, this can show up as position drift or a loss of fix in areas where the signal was previously solid. The fix is straightforward — keep the battery above that threshold by charging before long trips. A degraded original cell hits that floor faster than a fresh cell at rated capacity.

RoadMate 9250 shutting off without low-battery warning

The fuel gauge on the RoadMate 9250 reads relative to the original cell's discharge curve. A degraded or replacement cell with a slightly different curve can cause the indicator to read 20–30% remaining while the cell is already near cutoff voltage. The unit then shuts off without the expected warning. To recalibrate, run one full discharge-to-shutdown cycle followed by an uninterrupted charge to 100% — this lets the firmware re-anchor its gauge to the actual cell curve.