About this replacement
Acer Aspire Timeline 3810T Series — 10.8V Li-ion Replacement Battery (AS09D34)
This 10.8V, 4400mAh (47.52Wh) Li-ion battery replaces the original cell in the Acer Aspire Timeline 3810T and 3810TZ series notebooks. It fits the full range of 3810T variants, from the 6415 to the 8640, covering over 190 compatible models. OEM part numbers include AS09D34, AS09D36, AS09D56, AS09D70, and AS09D71, among others.
- 3810T series fit: All 3810T and 3810TZ variants share the same 10.8V three-cell-series configuration, connector pinout, and BMS handshake protocol. A battery verified on the base 3810T communicates correctly with the EC on every sub-model in this family.
- Bench tested on actual hardware: We ran this cell on a 3810T unit and confirmed the BMS negotiated charge cycles without fault codes. The protection circuit responded correctly to both charge cutoff and low-voltage disconnect thresholds.
- First-cycle calibration on the 3810T: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. The 3810T's BIOS uses this cycle to recalibrate its fuel gauge IC against the new cell's actual capacity, clearing the inaccurate health warning that appears after every cell swap.
Why the 3810T BIOS flags new cells as poor health immediately after swapping
The 3810T stores battery state data in EEPROM on the original cell. When a new cell goes in, the BIOS reads no charge history and flags the battery health as unknown or poor. This is not a fault with the replacement — it's a data gap the firmware cannot distinguish from a degraded cell. Run one full discharge-to-hibernate followed by a complete uninterrupted charge. After one to two of these learn cycles, the BIOS recalibrates and the health indicator updates correctly.
3810T shutting down at 20–30% charge shown on the gauge
This happens when the fuel gauge IC has not yet calibrated against the new cell's voltage curve. The gauge reports 20–30% remaining, but the cell voltage has already dropped below the BMS's cutoff threshold under CPU and display load combined. The firmware shuts the system down to protect the cell before the gauge catches up. Force a full discharge to hibernate, then charge to 100% without interruption — after two complete cycles the gauge aligns with actual cell voltage, and the early shutdowns stop.