About this replacement
Archos 40C Titanium — 3.7V Li-ion Replacement Battery (AC40CTI)
This is a 3.7V, 1200mAh Li-ion cell for the Archos 40C Titanium smartphone. It replaces part number AC40CTI directly. The 40C Titanium uses a compact form factor at 55.64 × 47.85 × 4.62mm — verify physical dimensions before fitting.
- 40C Titanium platform fit: The AC40CTI cell sits on a single-cell 3.7V rail with a passive protection circuit module. The connector pinout and PCM layout match the original board contacts, so no rewiring is needed on reassembly.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the 40C Titanium platform. The PCM held cutoff at the correct thresholds and the fuel gauge IC accepted the new cell without tripping a fault state.
- Fuel gauge recalibration on first use: After fitting, run one complete discharge to shutdown followed by a full charge before enabling any fast-charge mode. The 40C Titanium's fuel gauge IC was calibrated to the worn discharge curve of the original cell — one full cycle corrects the reference so percentage readings track accurately.
Sudden shutdown at 20–30% on the Archos 40C Titanium after a cell swap
A new cell has a steeper voltage discharge curve than a degraded one. The fuel gauge IC on the 40C Titanium still references the old curve, so it reads 25% when the actual cell voltage has already dropped close to the PCM cutoff threshold under screen or audio load. When current draw spikes, voltage collapses past the cutoff and the device shuts down instantly. Run one full discharge-to-shutdown cycle and a complete charge to let the coulomb counter re-anchor to the new cell's actual curve — shutdowns at false percentages stop after that cycle.
Archos 40C Titanium not powering on after storage
Li-ion cells in storage self-discharge over weeks. If the cell voltage drops below approximately 2.5V, the PCM enters lockout mode to prevent damage — the device shows nothing when you press power. Plug into a wall charger rather than a PC port, since a PC port may not source enough current to wake a locked-out PCM. Hold on the charger for at least 15–20 minutes before attempting to power on; once the cell climbs above 3.0V, the PCM releases and normal charging resumes.