Philips 315 4.8V Li-ion Replacement Battery 900mAh

Philips 315 / Diga / Spark / Twist Series — 4.8V Li-ion 900mAh Replacement Battery

This is a 4.8V Li-ion cell rated at 900mAh (4.32Wh), built to replace the original battery in the Philips 315, Diga, Spark, Twist, and two additional models in this series. It fits phones where the original cell has degraded, stopped holding a charge, or failed outright. Voltage and capacity match the original specification exactly.

• Philips 315-series platform fit: These models share the same voltage rail and connector footprint across the lineup. The BMS handshake protocol is consistent across this family, so the replacement cell communicates correctly with the charge IC on each supported device.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 315 platform. The BMS accepted the cell without fault codes, held the 4.8V nominal rail, and the charge IC terminated correctly at full capacity without overrun.
• Fuel gauge recalibration on first cycle: On first use after installation, run one complete discharge down to auto-shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's actual discharge curve before it starts reporting accurate percentages.

Sudden shutdown at 20–30% on the Philips 315 after cell replacement

This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell has a steeper voltage drop under load — especially during screen-on or network activity — so the phone hits the low-voltage cutoff threshold before the percentage counter reaches zero. The OS reads 25% but the actual cell voltage collapses under load and triggers the hardware shutoff. One full discharge-to-shutoff followed by a complete charge cycle resets the coulomb counter reference and eliminates most of these premature cutoffs.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge in storage. If the cell voltage has dropped below approximately 2.5V per cell, the BMS enters lockout mode to prevent damage — the phone will not respond to the power button or show a charging indicator. Connect the phone to a wall adapter (not a USB port) and leave it for 15–20 minutes without pressing any buttons. Once the charge IC pushes the cell above the BMS recovery threshold, the phone will show the charging screen and boot normally.