Capitel CBS718 Compatible Battery 3.7V 1050mAh

Capitel CBS718 / S718 — 3.7V Li-ion Replacement Battery

This is a 3.7V 1050mAh (3.89Wh) Li-ion cell for the Capitel CBS718 and S718 smartphones. It replaces the original battery when the phone no longer holds charge or shuts down unexpectedly. Dimensions are 55.42 × 35.01 × 5.41mm — measure your original before fitting if you are unsure.

• CBS718 and S718 compatibility: Both models run the same 3.7V battery bay and share connector placement, so one cell covers both. The BMS handshake requirements are identical across the two variants.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on compatible hardware. The BMS accepted charge at the correct CV/CC profile and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and complete one full discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before any high-current charging begins.

Sudden shutdown at 20–30% on the CBS718 after a cell swap

The CBS718's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell with a slightly different internal resistance profile hits a voltage cliff at a different state of charge. The phone's modem or screen draws a current spike, the voltage drops below the shutdown threshold, and the OS cuts power even though the reported percentage looks safe. One full discharge-to-shutdown followed by a complete charge resets the coulomb counter and resolves this.

Device not powering on after the battery sat in storage

Li-ion cells stored at low charge self-discharge over time. If the cell voltage drops below roughly 2.5V, the BMS enters a lockout state and blocks normal charging to prevent cell damage. The phone will appear completely dead. Connect to a wall charger — not a PC port — and leave it for 20–30 minutes without pressing any buttons. Most BMS circuits re-initialise once the charger pushes voltage back above the recovery threshold of approximately 2.9V.