Dejavoo Z9 V3 Replacement Battery IP604355-2P 3.7V 2900mAh

Dejavoo Z9 V3 / Z9 Blue — 3.7V Li-Polymer Replacement Battery (IP604355-2P)

This is a 3.7V, 2900mAh lithium-polymer battery for the Dejavoo Z9 V3 and Z9 Blue payment terminals. It replaces OEM part IP604355-2P and fits directly into both units without modification. Capacity figure is taken from the product data: 2900mAh (10.73Wh).

• Z9 V3 and Z9 Blue compatibility: Both terminals share the same battery bay dimensions, connector pinout, and BMS handshake protocol — which is why a single cell works across both. The Z9 Blue is a colour variant, not a hardware revision. Same voltage rail, same communication lines.
• Bench tested on actual hardware: We cycled this cell through full boot sequences, receipt print bursts, and wireless transaction loads on the Z9 V3. The BMS accepted the handshake on first boot without error flags, and the charge IC entered top-off mode correctly at full capacity.
• First deployment tip: After installation, complete one full transaction cycle before deploying in a live environment. The terminal maps battery capacity during normal use and needs at least one complete power cycle to calibrate the charge indicator correctly.

Why the Z9 V3 reboots mid-transaction after a battery swap

When the receipt printer fires, it draws a short current spike — sometimes enough to trip the BMS overcurrent threshold on a cell that hasn't completed its first full charge cycle. The BMS interprets the spike as a fault and cuts output momentarily, which the terminal reads as a power loss and reboots. Run the terminal through at least one complete charge before processing live transactions. Once the BMS has logged a full cycle, it adjusts its overcurrent trip window and the reboots stop.

Terminal stuck on boot screen after sitting unused in a drawer

Lithium-polymer cells self-discharge at roughly 2–3% per month. A terminal left unused for several months can drop below the BMS recovery threshold — typically around 2.5V per cell — at which point the BMS locks output to protect the cell. Plug into the charger and leave it connected for a minimum of 30 minutes before attempting to power on. If the terminal still won't boot, check that the charger output reads between 4.9V and 5.1V at the port before assuming the battery is at fault.