OQO G900 Compatible Battery 3.7V 1600mAh Li-Polymer

OQO G900 — 3.7V Li-Polymer Replacement Battery

This is a 3.7V, 1600mAh Li-Polymer replacement battery for the OQO G900 ultra-mobile PC. It fits the G900's internal battery bay and restores power to a platform where original cells have degraded after years of charge cycling. Capacity matches the OEM specification at 5.92Wh.

• G900 platform fit: The G900 uses a slim Li-Polymer cell sized to its compact chassis — 67.52 x 44.11 x 4.74mm. That footprint leaves no margin for fitment error, so the cell dimensions here are exact. The BMS on the G900 mainboard communicates directly with the battery, so a cell within spec voltage range initialises without a handshake fault.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under load conditions reflecting the G900's CPU and display draw. The BMS accepted the cell without throwing a protection cutoff, and voltage held stable across the discharge curve rather than collapsing early.
• Fuel gauge recalibration on first use: On the first cycle after installation, run the G900 down to automatic shutdown and then charge it fully without interruption. The G900's fuel gauge IC was calibrated against the old cell's discharge curve — one complete cycle resets that reference point and prevents the percentage counter from drifting.

Why the G900 reports wrong battery percentage after a cell swap

The G900 uses a coulomb-counting fuel gauge IC that builds its percentage model from the discharge history of the original cell. When you install a new cell, that stored curve no longer matches the new cell's actual capacity and voltage characteristics. The gauge keeps using the old reference, so it may report 40% while the cell is close to its real cutoff voltage. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to relearn the new cell's curve and brings percentage readouts back into alignment.

G900 shuts down suddenly at 20–30% remaining

This is a voltage cliff failure — the cell can no longer sustain its output voltage under the combined load of the CPU, display backlight, and storage controller. The fuel gauge still reads 20–30% based on its coulomb count, but the actual terminal voltage drops below the mainboard's minimum threshold and triggers an immediate shutdown. It happens on aged original cells and can also occur on a new cell if the fuel gauge IC hasn't yet recalibrated. Run one full discharge cycle first; if the shutdowns continue after that, check that the cell contacts are seated flat with no flex in the connector, as a loose connection increases effective resistance under load and worsens the voltage drop.