Samsung AB503442BABSTD Replacement Battery 3.7V 750mAh

Samsung SCH-R500 / SCH-R510 Series — 3.7V Li-ion Replacement Battery (AB503442BABSTD)

This is a 3.7V, 750mAh Li-ion replacement battery for the Samsung SCH-R500, SCH-R510, SCH-R610, and SGH-A127, among others. It replaces OEM part numbers AB503442BABSTD and AB503442CA. Fit the same compact 43.22 × 36.99 × 5.51mm cell footprint as the original.

• SCH-R500 / R510 / R610 and SGH-A127 platform: These models share the same battery bay dimensions, 3.7V voltage rail, and connector pinout. The BMS on each device expects the same charge termination voltage and current profile, so one cell covers the full group without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the SCH-R510. The BMS accepted the new cell without error flags, charge termination triggered correctly at 4.2V, and the protection circuit tripped as expected at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: On first install, run one full discharge down to auto-shutoff, then charge uninterrupted to 100%. The fuel gauge IC on these handsets was calibrated to the old cell's discharge curve — skipping this step leaves the coulomb counter reading against the wrong baseline.

Sudden shutdown at 20–30% on the SCH-R500 and R510

This happens when the cell voltage drops below the modem's minimum operating threshold under load, even though the fuel gauge still reads a usable percentage. The original cell's internal resistance has increased over hundreds of cycles — voltage sags sharply the moment the radio transmits or the screen peaks. A new cell with lower internal resistance holds voltage steady under the same load. After fitting a replacement, one full discharge-charge cycle resets the fuel gauge IC so the reported percentage aligns with actual cell voltage.

Phone not powering on after the battery sat in storage

Li-ion cells self-discharge during storage. If the cell voltage drops below roughly 2.5V, the BMS locks out to prevent damage — the phone will show nothing when you press the power button. Connect the device to a wall charger, not a PC USB port, and leave it for 15–20 minutes without pressing any button. The charge IC on these handsets needs a small trickle current to bring the cell above the BMS re-enable threshold before normal charging can begin. Once the battery icon appears, continue charging to full before first use.