Olympia Vox DRT043450-01 3.7V Compatible Battery

Olympia Vox — 3.7V Li-ion Replacement Battery (DRT043450-01)

This is a 3.7V, 1000mAh Li-ion cell for the Olympia Vox smartphone. It replaces the original DRT043450-01 battery when the existing cell can no longer hold adequate charge. Dimensions are 53.80 x 36.90 x 5.20mm — confirm these against your existing cell before installation.

• Olympia Vox fit: The Vox uses a compact battery bay with a fixed connector orientation. This cell matches the OEM footprint and connector pinout, so the BMS handshake between the battery and the phone's charge IC functions as the original cell does.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS held charge termination correctly and did not trip early under simulated screen and modem load.
• Fuel gauge calibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

Why the Vox reports wrong battery percentage after a cell swap

The Vox uses a fuel gauge IC that builds a discharge model from repeated charge and discharge cycles. When a new cell goes in, the IC still references the old cell's curve. The percentage shown on screen can read 40% while the actual cell voltage is already near the low-voltage cutoff. One full discharge down to automatic shutdown, followed by a full charge to 100%, forces the coulomb counter to reset and map the new cell's actual capacity. After that cycle, percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue. Under combined modem and screen load, the cell voltage drops faster than the fuel gauge IC expects, hitting the BMS low-voltage cutoff before the displayed percentage reaches zero. It is most common in the first few cycles on a new cell. Run the phone through two full discharge-charge cycles without fast charging. If shutdowns continue after that, check that the resting cell voltage after a full charge reads at least 4.15V — anything lower points to a charge termination fault in the phone's charge IC.