About this replacement
Philips Xenium CTS310X / S310X — 3.8V Li-ion Replacement Battery (AB2000LWMT)
This is a 3.8V 1800mAh Li-ion cell built to the AB2000LWMT specification for the Philips Xenium CTS310X and Xenium S310X smartphones. It replaces the original battery when capacity has degraded through repeated charge cycles. Voltage, connector, and physical dimensions (72.07 × 55.95 × 4.50mm) match the OEM spec.
- CTS310X and S310X compatibility: Both models share the same battery bay dimensions, 3.8V supply rail, and AB2000LWMT connector pinout. The BMS handshake protocol is identical across the two variants, so one cell covers both.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the CTS310X platform. The BMS accepted the cell without error, charge termination triggered correctly at 4.35V, and low-voltage cutoff engaged before cell damage could occur.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins on an uncalibrated counter.
Sudden shutdown at 20–30% on the Xenium CTS310X
This is the most common complaint after a cell swap on this platform. The fuel gauge IC still holds the discharge curve from the old, degraded cell. When the modem fires or the screen brightness spikes, current draw pulls the new cell's terminal voltage down faster than the old curve predicts. The phone reads 25% but the IC sees a voltage drop it interprets as imminent cutoff and shuts down. One full discharge cycle — run the phone down to auto-off, then charge uninterrupted to 100% — resets the coulomb counter against the actual new cell curve.
Phone not powering on after the replacement cell sat in storage
Li-ion cells self-discharge over time. If this battery sat in a warehouse or drawer for several months before installation, the resting voltage may have dropped below 3.0V. The Xenium's BMS will refuse to pass current to the board below approximately 2.5V per cell — a hard lockout to prevent unsafe charging of a deeply discharged cell. Connect the phone to a wall charger and leave it for 20–30 minutes before attempting to power on. The charge IC trickle-charges the cell back above the BMS threshold before switching to standard charge current. If the screen remains dark after 30 minutes on charge, try a second USB cable and a known-working 5V adapter.