Samsung SCH-R680 Repp Replacement Battery 3.7V 1700mAh

USCellular SCH-R680 Repp — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1700mAh Li-ion replacement battery for the Samsung SCH-R680 Repp smartphone, sold through USCellular. It fits directly in place of the original cell and supplies power to the processor, display, and cellular radio. Dimensions are 64.60 x 43.90 x 5.20mm — confirm yours match before ordering.

• SCH-R680 Repp fit: The Repp uses a removable 3.7V single-cell Li-ion pack with a three-contact connector carrying power and a thermistor line. Any replacement must match that contact layout and the physical envelope — this cell does both.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the SCH-R680 platform. The BMS accepted the cell without fault codes, and the charge IC stepped through trickle, bulk, and top-off phases normally.
• Fuel gauge recalibration on first use: On first use after installation, run one complete discharge down to auto-shutdown, then charge to 100% without interruption. The SCH-R680's fuel gauge IC uses that full cycle to map the new cell's discharge curve — skipping it causes the percentage readout to drift or jump for several days.

Why the SCH-R680 Repp reports wrong battery percentage after a cell swap

The Repp uses a coulomb-counter-based fuel gauge IC that stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual electrochemistry, so the percentage readout is working from bad data. The IC needs one uninterrupted discharge-to-shutdown and full recharge cycle to overwrite the old curve with data from the new cell. Until that cycle completes, readings can jump by 10–20% or report full charge prematurely. After one clean cycle, the gauge stabilises and tracks accurately.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem's minimum operating floor under load, even though the fuel gauge still shows charge remaining. The SCH-R680's LTE radio draws burst current during transmission, and a new cell with slightly higher internal impedance than expected can sag below 3.4V at that moment, triggering a protective shutdown. The fix is to complete two to three full discharge-recharge cycles — internal impedance drops as the cell forms, and the voltage sag narrows. If shutdowns continue past three cycles, check that the battery contacts on the phone are clean and making full contact, as even 0.1Ω of extra contact resistance worsens the sag.