Polaroid MID1047 Replacement Battery 3.7V 4700mAh BT-1529S0002

Polaroid MID1047 / MID1048 — 3.7V Li-Polymer Replacement Battery (BT-1529S0002)

This is a 3.7V, 4700mAh lithium-polymer battery for the Polaroid MID1047, MID1048, MIDK147, MIDS145PWE, and two additional MID-series tablets. It replaces part number BT-1529S0002. The cell matches the original's flat-pack form factor at 141.20 × 97.50 × 2.80mm, which matters on a tablet chassis with almost no tolerance for dimensional variation.

• MID-series compatibility: These Polaroid tablets share the same internal voltage rail at 3.7V nominal and use the same connector pinout and BMS handshake logic, which is why one cell covers the full MID1047 through MIDS145PWE range without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a MID1047 unit. The BMS accepted the new cell without fault codes, held charge to full cutoff, and discharged cleanly through display and WiFi load without premature voltage collapse.
• Post-swap calibration cycle: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. The fuel gauge IC calibrates against the new cell's actual capacity curve — skip this and the percentage display will read inaccurately from day one.

Tablet shutting down at 15–25% after battery replacement

The fuel gauge IC in these Polaroid tablets was calibrated to the old cell's discharge curve. When you install a new cell, that curve no longer matches, and the IC signals shutdown before the battery is actually empty. This typically shows up as sudden power-off anywhere between 15% and 25% on the status bar. The fix is one full discharge to automatic shutoff followed by an uninterrupted charge to 100% — this forces the IC to re-map the cutoff threshold against the new cell. After that cycle, the tablet should reach 0% indication before the hardware shuts down.

Percentage dropping faster than expected from a full charge

This is fuel gauge drift — the IC's stored reference data still reflects a degraded cell, so it compresses the displayed range and burns through percentage points quickly even though the physical charge level is fine. It is not a defective replacement cell. Run one complete discharge-to-shutoff and uninterrupted recharge cycle, and the IC will recalculate against the 4700mAh cell now installed. If the drop rate remains abnormal after two full cycles, check that the connector is fully seated — a partially connected cell raises internal resistance and causes genuine early voltage sag.