About this replacement
VeriFone V400M Series — 3.8V Li-Polymer Replacement Battery (BPK475-001-01)
This 3.8V, 3000mAh Li-Polymer battery replaces the original BPK475-001-01 in the VeriFone V400M, V400M Plus 4G, and M435-003-04-NAA-S payment terminals. It restores portable operation for merchants processing card transactions away from a fixed power source. Capacity is 11.4Wh — matching the original cell specification.
- V400M and V400M Plus 4G compatibility: Both models run the same 3.8V power rail, use the same connector pinout, and expect the same BMS handshake. A single cell covers both variants without modification or adapter.
- Bench tested on actual hardware: We cycled this cell through full boot sequences on the V400M, including receipt print jobs and contactless transaction loads. The BMS passed overcurrent checks and held voltage within spec across each test cycle.
- First-deployment tip for POS terminals: After installation, complete one full transaction cycle — including a receipt print — before deploying in a live environment. The terminal maps battery capacity during normal operation and requires at least one complete power cycle to calibrate the charge indicator correctly.
Terminal not completing PCI boot sequence after battery swap
The V400M runs a PCI-compliant security check during every boot. A new cell with an unrecognised BMS state can stall this sequence before the payment application loads. The terminal needs one full charge-and-boot cycle for the charge IC to accept the new cell's state-of-charge data. If the terminal hangs at the boot screen, connect it to the dock charger, let it reach full charge, then power cycle — it should complete the PCI sequence and reach the transaction screen normally.
Battery indicator stuck at 99% after the first charge
A new Li-Polymer cell enters top-off mode on its first charge cycle — the charge IC trickle-feeds the final percentage rather than cutting off cleanly at 100%. This is normal behaviour, not a fault with the battery or the terminal. The indicator will settle and read accurately once the cell completes its first full charge-discharge cycle. Run the terminal through one normal transaction session on battery, let it discharge to the low-battery warning, then recharge fully to reset the display.