About this replacement
Mitac Mio 8380 — 3.7V Li-Polymer Replacement Battery
This 3.7V 1450mAh Li-Polymer battery fits the Mitac Mio 8380 portable GPS navigation device. It replaces the original cell that powers the touchscreen display and onboard navigation processor. Capacity is 1450mAh (5.37Wh) — matched to the stock specification.
- Mio 8380 fitment: The 8380 uses a single Li-Polymer cell at 3.7V nominal. The onboard protection circuit manages charge termination and low-voltage cutoff. This replacement cell matches that voltage rail so the protection circuit operates within its intended thresholds.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The protection circuit accepted charge termination normally and the low-voltage cutoff triggered at the correct threshold with no anomalies in the charge curve.
- Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before use. The Mio 8380's fuel gauge IC is calibrated against the old cell's discharge curve — one full cycle corrects the reference and prevents erratic percentage readings.
Why the Mio 8380 shows wrong battery percentage after a cell replacement
The 8380's fuel gauge IC stores a learned discharge curve from the original cell. A new cell has a different impedance profile, so the IC's charge estimates drift immediately after the swap. The device may show 50% and shut down, or sit at 99% for an extended period. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to rewrite its reference curve against the new cell.
Mio 8380 not powering on after sitting in storage
Li-Polymer cells self-discharge during storage. If the cell voltage drops below approximately 2.5V, the protection circuit locks out and the device will not respond to a normal charge connection. Connect the unit to a charger and leave it undisturbed for 15–30 minutes — most chargers apply a low-current trickle that nudges the cell above the BMS re-enable threshold. If the device still shows no response after that period, check that the charge cable is delivering voltage with a known-working cable.