About this replacement
LeapFrog LeapPad3 — 3.7V Li-Polymer Replacement Battery (MLP654677)
This 3.7V, 2500mAh lithium-polymer battery replaces the original cell in the LeapFrog LeapPad3 children's educational tablet. It fits both the LeapPad3 and LeapPad 3 variants, which share the same battery bay and connector. OEM part numbers MLP654677 and 800-10066 both cross to this cell.
- LeapPad3 and LeapPad 3 compatibility: Both model names refer to the same hardware revision. The battery bay dimensions, connector orientation, and BMS handshake protocol are identical across the run, so one cell fits all units in this line.
- Bench tested on actual hardware: We cycled this cell on a LeapPad3 unit, confirmed BMS recognition on first boot, and verified the charge IC accepted the new cell without error flags or thermal events.
- Fuel gauge recalibration after swap: After fitting the new battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. This gives the fuel gauge IC a full reference cycle against the new cell and corrects the inaccurate percentage readings that commonly appear after a battery replacement.
LeapPad3 shutting down at 15–25% battery remaining
The LeapPad3 runs the display, WiFi, and audio simultaneously during active play. That combined load pulls enough current to trigger a voltage sag, where the cell voltage dips below the BMS cutoff threshold even though the reported percentage still shows charge remaining. The fuel gauge IC was calibrated to the old, degraded cell and does not map accurately to the new cell's discharge curve. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% resets this calibration and stops the premature shutdowns.
Battery percentage jumping or stuck after replacement
After a cell swap, the LeapPad3's fuel gauge IC still holds the impedance profile of the original battery. This causes the reported percentage to jump, freeze, or drop suddenly — typically in the 40–80% range. The IC needs one complete reference cycle to re-map its coulomb counter to the new cell. Discharge fully to automatic shutoff, then charge to 100% without interruption. After that single cycle, the percentage display tracks correctly.