Samsung EB504239HU S5200 Replacement Battery 3.7V 750mAh

Samsung S5200 / GT-S5200 / SGH-A187 — 3.7V Li-ion Replacement Battery (EB504239HU)

This is a 3.7V, 750mAh Li-ion cell built to the EB504239HU specification for the Samsung S5200, GT-S5200, GT-S5200C, and SGH-A187 smartphones. It slots into the same battery bay as the original and connects to the same three-contact terminal. Capacity is 750mAh (2.78Wh) — matched to the product data, not inflated.

• S5200 / SGH-A187 platform compatibility: These models share the same battery bay dimensions, connector pitch, and BMS handshake protocol. The EB504239HU part number covers all four variants — S5200, GT-S5200, GT-S5200C, and SGH-A187 — because Samsung used the same power rail and contact layout across this sub-family.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on an S5200 unit. The BMS accepted the charge handshake on the first cycle, voltage held steady at 3.7V nominal, and the protection circuit tripped correctly at the low-voltage threshold without false cutoffs.
• Fuel gauge recalibration on first use: After fitting this cell, run one full discharge-charge cycle with fast charging disabled. The S5200's fuel gauge IC was calibrated against your old cell's discharge curve — give it one full cycle to map the new cell before returning to normal charging behaviour.

Sudden shutdown at 20–30% on the S5200 after a cell swap

This happens because the fuel gauge IC on the S5200 still holds the discharge curve profile from the old, degraded cell. When the phone hits a modem transmission burst or screen wake, current draw spikes. The new cell's actual voltage at that load point doesn't match where the IC expects it to be, so the phone reads a safe percentage right up until voltage collapses under load. One full discharge-charge cycle — draining to auto-off, then charging uninterrupted to 100% — forces the coulomb counter to relearn the curve. After that cycle, the percentage readout tracks correctly.

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

Li-ion cells shipped or stored in a partially discharged state can drop below 2.5V per cell during transit or long shelf time. The S5200's BMS locks out at that threshold to prevent cell damage, and the phone will show no response — no charging animation, no startup. Connect the phone to a wall charger (not a USB port) and leave it untouched for 20–30 minutes. The charge IC trickle-charges the cell back above the BMS re-enable threshold, typically around 2.9V, at which point normal charging resumes and the phone will power on.