About this replacement
Asus F70 / G71 Series — 14.8V Li-ion Replacement Battery (A42-M70)
This is a 14.8V, 4400mAh (65.12Wh) Li-ion battery for the Asus F70, F70s, F70sl, G71, and compatible models. It replaces OEM part numbers A42-M70, A41-M70, A32-M70, and a range of 70-N and 90-N series part numbers used across this platform. When your original cell degrades and the laptop loses portable power, this is the direct swap.
- F70 and G71 platform compatibility: These models share a common 14.8V battery rail, identical connector pinout, and the same BMS handshake protocol — which is why one cell covers the full range. The battery's EEPROM is pre-loaded with capacity data the Asus EC firmware expects on this platform.
- Bench tested on actual hardware: We ran this cell through charge-discharge cycles on an F70 chassis. The BMS communicated cleanly with the EC, charge current tapered correctly at the CV stage, and the fuel gauge IC registered capacity without throwing an unknown-battery flag.
- First-cycle calibration on the F70: After installing, run the laptop on battery until it hibernates at low charge, then charge uninterrupted to 100% without using the machine. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor immediately after fitting a new cell
The Asus F70 EC reads EEPROM data stored in the old battery and compares it against the new cell on first boot. Because the EEPROM cycle count and capacity history don't match the fresh chemistry, the firmware flags the battery as degraded — even when it is brand new. This is not a fault with the replacement cell. Run one full discharge-to-hibernate cycle followed by a complete uninterrupted charge, and the BIOS learn cycle will re-anchor to the new cell's actual capacity. After two to three cycles, the health indicator should return to normal.
Laptop shutting down at 20–30% charge shown on the F70
This happens when the fuel gauge IC hasn't yet calibrated against the new cell's voltage curve. The IC inherited the old cell's discharge profile, so it miscalculates the voltage cliff — the point where cell voltage drops sharply under combined CPU and display load. The laptop hits that cliff at what looks like 20–30% remaining. Run two full discharge-to-hibernate cycles charged back to 100% each time, and the fuel gauge will remap the curve to the new cell. After calibration, the reported percentage and actual cutoff voltage — around 11.1V under load — should align.