Nextbase DashCam 402G Compatible Battery 3.7V 180mAh

Nextbase DashCam 402G / 412GW / 512G — 3.7V Li-Polymer Replacement Battery

This 3.7V 180mAh (0.67Wh) Li-Polymer battery fits the Nextbase DashCam 402G, 412GW, and 512G. It replaces the internal cell that powers the dashcam during recording and buffers footage when the ignition cuts out. The battery sits inside the dashcam body and is not user-removable under normal operation — replacement is a workshop-level task.

• 402G, 412GW, and 512G compatibility: These three dashcam models share the same PCB footprint and battery bay dimensions — 30.60 x 16.00 x 5.10mm — along with a common 3.7V charge circuit. A cell that fits one will seat correctly in the others without modification to the connector.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The protection circuit cut in cleanly at the low-voltage threshold, and charge acceptance held steady across repeated cycles with no swelling observed.
• Post-installation charging: After fitting, connect the dashcam to a powered USB source for a full charge before mounting in the vehicle. Li-Polymer cells shipped in storage state need a complete charge cycle before the dashcam's capacitor-backup logic will function correctly at ignition cutoff.

Why the 402G fails to save the final clip when the engine stops

The 402G uses its internal battery as a buffer — when the vehicle's ignition cuts power, the battery keeps the unit alive long enough to write the last recording segment to the SD card. A degraded or dead cell means that buffer window collapses, and the final clip is lost or corrupted. This is the most common reason buyers search for a replacement cell. The battery does not power extended recording; it handles only the write-completion window after power loss.

Dashcam powers on but shuts down immediately after ignition cut

If the dashcam powers off the instant the car loses ignition rather than completing its shutdown sequence, the internal cell has dropped below the minimum voltage the BMS will discharge to — typically around 3.0V on Li-Polymer cells of this spec. The protection circuit opens under load and the dashcam loses power before it can finalise the file. Fitting a new cell restores the buffer. After installation, run a full charge cycle to bring the cell to 4.2V before testing shutdown behaviour.