SJCAM SJ4000B DX 288812 Replacement Battery 3.7V 900mAh

SJCAM DX 288812 Series — 3.7V Li-ion Replacement Battery (SJ4000B)

This is a 3.7V, 900mAh Li-ion replacement battery for the SJCAM DX 288812 and DX 288813 action cameras, as well as the Sports Cam W7 and W8 models. It replaces OEM part numbers SJ4000B and GP200. Dimensions are 32.77 × 29.16 × 10.89mm — match these against your existing cell before ordering.

• Compatible across the DX 288812 family: These models share the same physical cell format, 3.7V nominal voltage rail, and connector pinout. A single cell specification covers the full group without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the DX 288812 body. The BMS accepted the cell, voltage read correctly at the terminals, and the camera body reported charge status without error flags.
• First-use charge cycle on the DX 288812: Run the first full charge inside the camera body using the OEM cable — not a generic USB charger. Some SJCAM bodies need one in-camera charge cycle before the battery-remaining indicator maps correctly to the new cell's discharge curve.

Battery percentage jumping erratically on the DX 288812 display

SJCAM's battery indicator maps voltage thresholds to display segments calibrated around the original cell's discharge curve. A new replacement cell can have a slightly different discharge profile, causing the indicator to skip or jump between levels mid-use. This is a firmware mapping issue, not a fault with the cell itself. One complete charge-and-discharge cycle inside the camera body usually re-anchors the thresholds — after that, the indicator tracks the charge level accurately.

DX 288812 showing dead battery icon on a replacement cell that still has charge

If the camera cuts off or shows a dead cell icon before the battery is genuinely depleted, the BMS is reading the resting voltage and applying the OEM low-voltage cutoff threshold. A replacement cell resting below 3.5V after shipping can trigger this even when the cell has usable capacity remaining. Place the cell in the camera and charge fully before first use — do not attempt to power on from a shipped state. Once the cell reads at or above 3.7V at the terminals, the cutoff error clears and the camera powers normally.