About this replacement
Apple iPad Pro 12.9 2nd Gen — 3.77V Li-Polymer Replacement Battery (A1754)
This 3.77V, 10800mAh (40.72Wh) Li-Polymer battery replaces part number A1754 and 020-01238 in the Apple iPad Pro 12.9-inch 2nd Generation (2017), covering models A1670 and A1821. It powers the display, processor, cellular modem, and all onboard functions. Swap it when the original cell no longer holds a charge or shuts down unexpectedly under load.
- A1670 and A1821 model coverage: Both the Wi-Fi and Wi-Fi + Cellular variants of the 12.9-inch 2nd Gen use the same connector pinout, voltage rail, and BMS communication spec — one cell covers both board revisions without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a 2nd Gen 12.9-inch unit. The BMS handshake completed without error flags, charge acceptance was normal across the full capacity range, and the fuel gauge IC recognised the new cell correctly after a recalibration cycle.
- Post-installation fuel gauge reset: After fitting this battery, run the iPad down to automatic shutoff, then charge it uninterrupted to 100% without using the device. This resets the fuel gauge IC calibration against the new cell's actual voltage curve and eliminates the inaccurate percentage readings that almost always appear after a swap.
iPad Pro 12.9 shutting down at 15–25% after battery replacement
The 12.9-inch Pro pulls hard on the battery when the ProMotion display, WiFi radio, and Apple A10X chip are all active simultaneously. The original fuel gauge IC was calibrated to the old cell's discharge curve, so when voltage drops under that combined load, the IC interprets it as a critically low state before the actual capacity is exhausted. The result is an unexpected shutdown even though the percentage display still shows double digits. One complete discharge-to-shutoff followed by an uninterrupted charge to 100% re-maps the IC to the new cell and stops the early cutoff.
USB-PD fast charging unavailable on the first charge after a battery swap
iPadOS negotiates USB Power Delivery charging rates through a software layer that checks battery state on every boot. On the first charge cycle after a replacement, the system often defaults to standard 5W input while it validates the new cell's response. This is expected behaviour — not a fault with the battery or the cable. Complete one full charge cycle to 100%, then unplug and reconnect your USB-C PD adapter. Fast charging should resume from the second cycle onward at the correct negotiated rate.