TomTom Start VF9B Compatible Battery 3.7V 770mAh

TomTom Start / Start2 Series — 3.7V Li-ion Replacement Battery (VF9B)

This is a 3.7V, 770mAh Li-ion cell built to replace the original battery in the TomTom Start, Start2, 1EX00, and Easy portable GPS navigators. It uses OEM-matched part numbers VF9B, VF9, AHL03707002, and AHL03706001. Fit the cell and the device operates untethered from vehicle power again.

• Start and Start2 compatibility: Both units share the same battery bay dimensions, connector pinout, and 3.7V charge rail. The BMS on each model accepts this cell without modification or firmware change.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a TomTom Start unit. The BMS accepted the cell immediately, charged to 4.2V without error flags, and held the cutoff threshold at the correct low-voltage point.
• Cold-start satellite acquisition after fitting: After any full power interruption, the GPS receiver loses its ephemeris data and must run a cold start. Take the unit outside to an open sky and power it on before driving — first fix takes 5–10 minutes. Subsequent warm starts drop to under a minute once the device has saved fresh satellite data.

Why the TomTom Start loses saved routes after a battery swap

The Start stores active routes and recent destinations in volatile RAM backed by the main battery. When the battery is fully removed, that memory loses power and the stored data is cleared. Saved favourites written to internal flash survive the swap, but any route that was active or recently calculated may not. Before removing the old cell, note down any custom waypoints you need — they cannot be recovered from the battery itself.

TomTom Start shutting off without a low-battery warning

The battery indicator on the Start is calibrated against the original cell's discharge curve. A new or aged cell with a slightly different internal resistance can shift the voltage reading, so the device hits its hardware cutoff before the on-screen indicator reaches one bar. Run two full charge and discharge cycles after fitting the new cell — the firmware recalibrates the gauge against the actual cell behaviour. After calibration, the low-battery warning should appear reliably above 3.4V.