Mitac Mio Spirit 300 GPS Replacement Battery 3.7V 720mAh

Mitac Mio Spirit 300 Series — 3.7V Li-ion Replacement Battery (07917TSIP)

This 3.7V, 720mAh lithium-ion cell replaces the OEM battery in the Mio Spirit 300, Spirit 300 Traffic, Spirit 555, and Spirit 555 Traffic GPS navigators. It fits the same physical footprint at 49.95 × 36.05 × 5.59mm and connects to the same BMS circuit in each model. Swap it in when the original cell no longer holds enough charge to complete a route.

• Spirit 300 and 555 platform compatibility: Both the standard and Traffic variants run the same 3.7V cell on a shared PCB layout. The connector pinout and BMS handshake are identical across the family, so one cell covers all four models without any modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Spirit platform and confirmed the BMS accepted the new cell without fault flags. Charge acceptance was clean from the first cycle, and the protection circuit responded correctly to both overcharge and undervoltage thresholds.
• Cold-start recalibration after fitting: After fitting this cell, power the unit on outdoors and let it acquire a full satellite fix before driving. GPS units perform a cold start after any full power interruption — first fix can take 5–10 minutes outdoors versus under a minute on subsequent warm starts.

GPS accuracy dropping as the Spirit 300 battery depletes

At low state of charge, some GPS receivers step down the power allocated to the RF front-end to protect the remaining voltage. On the Spirit 300, this can appear as wider position scatter or slower reacquisition after a tunnel. The receiver is not failing — it is operating at reduced sensitivity. A fully charged cell restores normal receiver gain. If accuracy issues persist with a full charge, the problem is antenna or signal environment, not the battery.

Spirit 300 shutting off without a low-battery warning

This happens when the fuel gauge has not calibrated to the new cell's actual discharge curve. The unit's voltage-threshold indicator is still reading against the old depleted cell's profile, so the visual warning never triggers before the cutoff voltage is hit. Run one full charge-to-cutoff cycle without interruption to let the gauge recalibrate. After that cycle, the low-battery warning should reappear at the correct point — typically around 3.4V under load.