About this replacement
Prestigio PSP3507 DUO — 3.7V Li-ion Replacement Battery
This is a 3.7V 1800mAh Li-ion replacement battery for the Prestigio PSP3507 DUO and MultiPhone PSP3507 DUO. It replaces the original cell when capacity has dropped through normal charge cycling and the phone can no longer hold adequate charge through a day of use. Capacity is rated at 6.66Wh, matching the original cell specification.
- PSP3507 DUO and MultiPhone PSP3507 DUO compatibility: Both variants share the same battery bay dimensions, connector pinout, and BMS communication protocol — the same cell works across the entire PSP3507 DUO platform without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the PSP3507 DUO, confirmed BMS handshake, and verified the charge IC accepted the cell without triggering a fault or cutoff event.
- Fuel gauge recalibration on first use: On first installation, disable any fast charge option and run one complete discharge-to-charge cycle at standard current. This gives the fuel gauge IC a clean reference against the new cell's discharge curve before higher charge currents are applied to an uncalibrated cell.
Sudden shutdown at 20–30% on the PSP3507 DUO after cell swap
This happens because the fuel gauge IC is still using the discharge curve it mapped from the old, degraded cell. The new cell has a steeper voltage cliff at lower state-of-charge than the old cell did, so the phone cuts power before the reported percentage reaches zero. The BMS is doing its job — it sees cell voltage drop below the safe floor under modem or display load and shuts down. One full discharge-charge cycle resets the coulomb counter reference and the shutdowns stop.
Phone warm near the battery compartment during the first charge
A fresh Li-ion cell has higher internal impedance than a cell that has been through several charge cycles. The charge IC pushes current into higher resistance, and that resistance converts some energy to heat. This is normal on cycle one and two — not a fault. If the phone is still noticeably warm by cycle three, check that the USB cable and charger output match the rated 5V input. Warmth that persists past the first two cycles points to a charger output issue, not the cell.