About this replacement
HP ElitePad 900 / 900 G1 — 7.4V Li-Polymer Replacement Battery (HSTNN-DB3U)
This 7.4V, 3350mAh (24.79Wh) lithium-polymer battery replaces the original cell in the HP ElitePad 900 and ElitePad 900 G1 tablets. It fits the slim 3.41mm profile of the ElitePad chassis and connects to the same internal charge circuit. OEM part numbers HSTNN-DB3U, AT02XL, and 685987-001 all cross to this cell.
- ElitePad 900 and 900 G1 fit: Both generations share the same internal bay dimensions, connector pinout, and BMS handshake protocol — the 7.4V voltage rail and cell footprint are unchanged between them. One replacement covers both variants.
- Bench tested on actual hardware: We ran this cell through the ElitePad charge IC and confirmed the BMS negotiates correctly at both trickle and full charge rates. The protection circuit trips at the correct cutoff voltage under combined display and WiFi load.
- Fuel gauge reset after installation: After fitting this battery, run one full discharge to automatic shutoff, then charge uninterrupted to 100% without using the tablet. This resets the fuel gauge IC calibration against the new cell — skipping this step causes the percentage display to read inaccurately for days.
Why the ElitePad 900 shuts down at 15–25% remaining
The ElitePad's charge controller reads cell voltage to estimate remaining capacity, but after a battery swap it still references the discharge curve of the old, degraded cell. When the new cell hits roughly 3.6V per cell under combined display, WiFi, and CPU load, the voltage briefly sags below the controller's shutdown threshold — even though the cell physically has charge left. The firmware interprets this sag as end-of-charge and cuts power. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% writes a new curve to the fuel gauge IC and resolves this.
HP ElitePad 900 reporting 0% or stuck percentage after battery swap
A stuck or frozen percentage reading after installation means the fuel gauge IC is still calibrated to the old cell's impedance profile. The controller hasn't seen a full charge-discharge cycle on the new cell, so it has no reference points to interpolate from. Power the tablet fully off, charge to 100% with the screen off, then drain to automatic shutoff in a single session. After the next full charge, the percentage display tracks correctly against actual cell voltage.