About this replacement
Schok Flip SC3218T / SC3218B — 3.8V Li-ion Replacement Battery (SB2000)
This 3.8V, 2100mAh Li-ion cell replaces the OEM SB2000 battery in the Schok Flip SC3218T and SC3218B. It fits the same physical footprint at 63.50 × 50.00 × 5.50mm and drops into the battery bay without modification. Capacity figures come from the product data — 7.98Wh total energy storage.
- SC3218T and SC3218B share the same cell: Both variants use the same SB2000 form factor, voltage rail, and connector pinout. The BMS handshake is identical across both board revisions, so one cell covers both models without any firmware distinction.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the SC3218T chassis. The BMS accepted charge current without tripping, held voltage above 3.6V through mid-discharge, and terminated charge cleanly at full capacity.
- Fuel gauge recalibration on first install: After fitting this cell, disable fast charging and run one full discharge-to-charge cycle before normal use. The fuel gauge IC on the SC3218T is calibrated to the old cell's discharge curve. One complete cycle lets the coulomb counter re-anchor its endpoints to the new cell before fast charge pushes high current into an uncalibrated measurement baseline.
Sudden shutdown at 20–30% on the Schok Flip SC3218T
This is a voltage cliff failure. The modem radio on a flip phone draws a sharp current spike during a call or data burst. If the cell cannot sustain voltage under that load, it sags below the BMS cutoff threshold — typically 3.0V — and the phone shuts off even though the fuel gauge still shows charge remaining. A new cell with full capacity handles the load spike without sagging. If shutdowns persist after fitting this replacement, run the phone down to 5% on one full cycle to force the coulomb counter to reset its low-voltage anchor point.
Phone won't power on after the battery sat in storage
Li-ion cells self-discharge in storage. If the cell drops below 2.5V per cell, the BMS locks out charge input as a protection measure — the phone appears completely dead and won't respond to the charger. Connect the phone to a charger and leave it untouched for 15–30 minutes. Most chargers trickle a small pre-charge current below the BMS lockout threshold, which nudges the cell voltage back above 2.5V and allows the BMS to re-initialise. Once the BMS unlocks, normal charging resumes and the phone will boot.