TomTom Start XL GPS Replacement Battery 3.7V 900mAh

TomTom Start XL — 3.7V Li-ion Replacement Battery (P11P16-22-S01)

This is a 3.7V, 900mAh Li-ion cell for the TomTom Start XL portable GPS navigator. It fits the Start XL and the 4ET0.002.07 variant. Swap it when the original cell no longer holds a charge or the unit shuts off unexpectedly during navigation.

• Start XL and 4ET0.002.07 compatibility: Both units run the same 3.7V single-cell architecture with identical connector pinout and BMS handshake requirements. The cell footprint is 52.30 × 34.00 × 6.50mm — measure your bay before ordering if you are unsure of your exact variant.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Start XL platform. The BMS accepted the cell without error flags, voltage held stable across GPS receiver and display load, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Cold-start satellite acquisition after fitting: After any full power removal, the Start XL loses its ephemeris data and must perform a cold start. Power the unit on outdoors with a clear sky view and allow 5–10 minutes for first satellite fix. Subsequent warm starts return to under a minute once the data is cached again.

GPS accuracy reduced at low battery on the Start XL

The Start XL scales back GPS receiver sensitivity when the cell voltage drops toward the low-voltage threshold. This is a firmware-level power saving measure, not a hardware fault. The effect is reduced satellite count and occasional position drift on the map. Keeping the cell above 3.5V under load — or charging before long trips — keeps the receiver running at full sensitivity.

Start XL shutting off without low-battery warning

The fuel gauge on the Start XL reads the battery percentage by tracking voltage curve, not true coulomb counting. A worn or new-but-uncalibrated cell can have a compressed voltage curve that skips the warning threshold entirely. The unit reads 20% and then hits the cutoff voltage almost immediately under GPS and display load. Run two or three full charge-to-shutdown cycles to let the firmware recalibrate its voltage-to-percentage mapping — the warning should appear correctly around 3.6V after that.