TomTom Via 120 GPS Compatible Battery 3.7V 700mAh KM1

TomTom Via 120 / Via Live 120 Series — 3.7V Li-ion Replacement Battery (KM1)

This is a 3.7V 700mAh Li-ion cell for the TomTom Via 120, Via 125, Via Live 120, and Via Live 125 portable GPS navigators. It replaces OEM part KM1 and matches the original cell's dimensions at 35 × 35 × 5mm. Swap it when the original no longer holds charge or the device shuts off unexpectedly mid-route.

• Via 120 and Via Live series fit: These models share the same battery bay geometry, connector orientation, and 3.7V power rail. A single cell covers the full Via 1xx lineup because TomTom used the same PCB layout and BMS handshake threshold across this generation.
• Bench tested on actual hardware: We ran this cell on a Via 120 unit and confirmed the BMS accepted charge from the OEM cradle charger without fault flags. Charge current ramp and cutoff voltage behaved identically to the original cell at 4.2V termination.
• Cold-start satellite acquisition after swap: After fitting this cell, power the navigator fully on outdoors before driving. The GPS performs a cold start after any full power interruption — first satellite fix can take 5–10 minutes. Subsequent warm starts drop to under a minute once almanac data is cached.

GPS accuracy reduced at low battery on the Via 120

When cell voltage drops toward 3.5V, the Via 120 reduces power to the GPS receiver module to extend operation. That power reduction lowers receiver sensitivity, which weakens satellite signal acquisition — particularly under tree cover or in urban canyons. You may notice the position dot drifting or route recalculations increasing before any low-battery icon appears on screen. Fitting a fresh cell at full 3.7V nominal restores the receiver to full sensitivity.

Device shuts off mid-route without a low-battery warning

A degraded cell loses voltage quickly under the combined load of the GPS receiver, display backlight, and map rendering. The fuel gauge on the Via 120 reads remaining charge from open-circuit voltage, which doesn't account for how fast voltage collapses under active load. The result is a shutdown that hits the 3.4V cutoff threshold before the warning icon has time to appear. After fitting this replacement, run one full charge-to-discharge cycle with active navigation to let the device recalibrate its voltage-to-charge mapping.