Archos OXYGEN 57 Replacement Battery 3.8V 2000mAh AC570X

Archos OXYGEN 57 — 3.8V Li-ion Replacement Battery (AC570X)

This is a 3.8V, 2000mAh Li-ion battery for the Archos OXYGEN 57 smartphone. It replaces the original AC570X cell when capacity has degraded or the battery no longer holds a charge. Dimensions are 84.20 × 60.00 × 4.20mm — verify clearance before fitting.

• OXYGEN 57 fitment: The AC570X uses a single-cell 3.8V nominal rail with a two-wire thermistor line feeding the charge IC. The connector and PCB protection circuit match the OXYGEN 57 motherboard — no adapter or rewiring needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the OXYGEN 57 platform. The BMS passed overcurrent and over-voltage cutoff checks, and the charge IC accepted the cell without fault flags on the third cycle.
• First-cycle fast charge hold-off: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current charging begins. Charging at standard rate on cycle one avoids pushing current into an uncalibrated coulomb counter.

Sudden shutdown at 20–30% on the OXYGEN 57 after a cell swap

This happens because the fuel gauge IC is still running the discharge curve it mapped to the old, degraded cell. When the new cell's actual voltage under modem or display load drops faster than the IC expects, the phone reads a false state-of-charge. The SoC hits a low-voltage trip point the OS never warned you about. One full discharge down to auto-shutdown, followed by an uninterrupted charge to 100%, forces the coulomb counter to re-anchor to the new cell's curve.

OXYGEN 57 not powering on after the battery sat in storage

Li-ion cells self-discharge in storage, and if the cell dropped below approximately 2.5V, the BMS enters lockout to prevent an unsafe charge condition. The phone will show no response — no boot screen, no charge indicator. Connect to a wall adapter, not a PC USB port, and leave it for 20–30 minutes before attempting to power on. If the cell recovers past the BMS re-enable threshold of around 2.8V, the charge IC will resume normal operation.