Samsung Galaxy S4 SCH-i535 Replacement Battery 3.8V 2100mAh

Verizon SCH-i535 / Galaxy S3 — 3.8V Li-ion 2100mAh Replacement Battery

This 3.8V Li-ion cell replaces the original battery in the Samsung Galaxy S3 (SCH-i535, SCHI535ZKB) on Verizon's network. Capacity is 2100mAh (7.98Wh), matching the stock cell's footprint and connector. It fits the standard removable-back slot without modification.

• SCH-i535 and SCHI535ZKB compatibility: Both model strings refer to the same Verizon Galaxy S3 hardware. The battery connector, cell dimensions (63.20 × 50.40 × 5.40mm), and BMS handshake requirements are identical across these SKUs — one cell covers both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on an SCH-i535 unit. The BMS accepted the cell without triggering an authentication error, and the charge IC transitioned through pre-charge, constant-current, and constant-voltage phases cleanly.
• Fuel gauge recalibration on first use: After installing this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100% before resuming normal use. The Galaxy S3's fuel gauge IC uses a coulomb counter calibrated to the old cell's discharge curve — skipping this step causes the OS to report inaccurate percentages from day one.

Sudden shutdown at 20–30% on the SCH-i535 after a cell swap

The Galaxy S3's Exynos or Snapdragon SoC — depending on carrier variant — draws a sharp current spike when the modem switches to LTE. If the fuel gauge IC still holds the old cell's discharge curve in memory, it miscalculates remaining capacity and cuts power before the cell is actually depleted. The phone reads 25% and shuts down because the internal voltage model says the cell has hit its floor. One full discharge-charge cycle forces the coulomb counter to relearn the new cell's actual voltage-to-capacity relationship. After that recalibration cycle, shutdown at false-low percentages stops.

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

Li-ion cells self-discharge roughly 2–3% per month in storage. If this battery shipped or sat unused long enough to drop below 2.5V per cell, the BMS enters a protective lockout and blocks normal charging current. The Galaxy S3 will show nothing on screen — no charging animation, no boot. Connect to a wall charger (not a PC USB port) and leave it for 20–30 minutes; the charge IC delivers a low trickle current to bring the cell above the 3.0V recovery threshold before switching to normal charge current. If the screen still shows nothing after 30 minutes, try a different cable — the SCH-i535's micro-USB port is the first failure point at this stage.