About this replacement
TomTom Pro 8270 Series — 3.7V Li-ion Replacement Battery (UZ6)
This is a 3.7V, 2000mAh Li-ion cell replacing OEM part UZ6 in the TomTom Pro 8270, Pro 8275, Bridge, and 4F173 GPS navigators. It slots into the same footprint as the original at 65.50 × 50.80 × 5.30mm. Fit the cell when the original no longer holds a charge through a full navigation session.
- Pro 8270 / Pro 8275 / Bridge / 4F173 fit: These four models share the same battery bay dimensions, connector pinout, and 3.7V voltage rail, so one cell covers the whole group without modification.
- Bench tested on actual hardware: We ran the cell through charge and discharge cycles on the Pro 8270 platform. The BMS accepted full charge without error flags and the device powered on cleanly at each stage of the cycle.
- Cold-start satellite acquisition after swap: After fitting this cell, power the GPS fully 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 drop to under a minute once almanac data is cached.
GPS accuracy dropping at low battery on the Pro 8270
When cell voltage falls below roughly 3.5V, some TomTom Pro units reduce receiver sensitivity to lower current draw. This shows up as position drift or a wider accuracy circle on the map — not a GPS signal issue. The fix is straightforward: a fresh cell running at nominal 3.7V restores the receiver to full sensitivity. If you see accuracy problems early in a session, check whether the old battery is voltage-sagging under the display and GPS receiver load.
Device shuts off without warning before the low-battery indicator appears
This happens when the on-device battery gauge is calibrated to an aged cell, not the replacement. The firmware's low-battery threshold is tied to a voltage curve that no longer matches a fresh 2000mAh cell. The device reads the voltage correctly but maps it to the wrong state-of-charge percentage, so the visual warning never fires before cutoff. Run two full charge-to-discharge cycles to let the firmware recalibrate its voltage-to-capacity mapping — the warning indicator should align by the third cycle.