Samsung Galaxy S Relay 4G EB-L1K6ILZ Replacement Battery 3.7V 3600mAh

Verizon SCH-i415 / Galaxy S Relay 4G — 3.7V Li-ion Replacement Battery (EB-L1K6ILZ)

This is a 3.7V, 3600mAh Li-ion replacement battery for the Samsung Galaxy S Relay 4G, sold on Verizon as the SCH-i415 and SCH-I415SAAVZW. It also fits the Stratosphere II. The OEM part number this cell replaces is EB-L1K6ILZ.

• SCH-i415 and Stratosphere II compatibility: Both devices share the same physical battery bay dimensions and the same 3.7V single-cell Li-ion architecture. The connector pinout and BMS communication protocol are identical across this model family, so one cell covers all variants listed.
• Bench tested on actual hardware: We ran this cell through full charge and load cycles on the SCH-i415. The BMS accepted the charge handshake without error, held voltage above 3.5V under screen-on load, and tripped the protection circuit correctly at the low-voltage threshold.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge-charge cycle at standard current. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes energy into an uncalibrated state register.

Sudden shutdown at 20–30% on the SCH-i415 after a cell swap

This is a voltage cliff issue, not a capacity problem. Under heavy load — active LTE modem, screen at full brightness, GPS running — the new cell's internal resistance causes voltage to sag below the BMS cutoff threshold even when the reported percentage still looks safe. The fuel gauge IC is reading a state-of-charge curve calibrated to the old, degraded cell, so the percentage shown is inaccurate. One full discharge-to-shutdown followed by an uninterrupted charge to 100% lets the coulomb counter reset against the new cell's actual curve.

Phone won't power on after the EB-L1K6ILZ sat in storage

Li-ion cells that discharge below approximately 2.5V per cell during extended storage trigger a BMS lockout — the protection circuit opens and blocks current flow as a safety measure. A standard charger may not deliver enough trickle current to recover the cell from this state. Connect the phone to a wall adapter rated at least 5V/1A and leave it undisturbed for 20–30 minutes before attempting to power on — this gives the BMS time to detect the incoming current and exit lockout. If the charging indicator does not appear after 30 minutes, the cell has dropped below recoverable voltage and needs replacement.