About this replacement
Acer Aspire One 532h Series — 10.8V Li-ion Replacement Battery (UM09G31)
This is a 10.8V, 4400mAh (47.52Wh) Li-ion replacement battery for the Acer Aspire One 532h netbook series. It fits the 532h-2Db, 532h-2Dr, 532h-2Ds, 532h-21s, and over 45 additional Aspire One 532h variants. OEM part numbers covered include UM09G31, UM09G41, UM09G51, UM09H31, UM09H41, and several others in the UM09 family.
- 532h series compatibility: Every Aspire One 532h variant in this lineup shares the same 10.8V rail, UM09-series connector pinout, and BMS handshake protocol — so one cell pack covers the full range without modification.
- Bench tested on actual hardware: We ran this pack on the 532h platform and confirmed the BMS negotiated correctly with the Acer EC firmware. Charge acceptance reached full capacity and the fuel gauge IC tracked cell voltage without dropping out mid-cycle.
- Post-install calibration on the 532h: After fitting this battery, run one full discharge until the netbook hibernates at the low-voltage cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the Aspire One 532h shuts down at 20–30% charge remaining
The 532h uses a fuel gauge IC that builds a charge map against the original cell's impedance curve. When a new cell is installed, the stored map no longer matches actual cell behaviour. The EC firmware hits its low-voltage protection threshold earlier than the displayed percentage suggests — triggering an abrupt shutdown. Running two to three full discharge-recharge calibration cycles rewrites the map against the new cell and brings the shutdown point back in line with the displayed percentage.
BIOS reporting the replacement battery as poor health or unknown
This is an EEPROM data mismatch, not a fault with the new cell. The Acer BIOS compares the incoming battery's EEPROM health data against the previous cell's logged cycle count and capacity history. A fresh cell with zero cycles reads as anomalous and triggers the warning. Run the battery learn cycle — full discharge to hibernate cutoff, then a full uninterrupted charge — and the BIOS health indicator will update to normal on the next boot.