Boifun 2S Baby Monitor Replacement Battery 3.7V 3000mAh

Boifun 2S / 2TM / 5S / 6T — 3.7V Li-Polymer 3000mAh Replacement Battery

This 3.7V 3000mAh lithium-polymer battery replaces the internal cell in the Boifun parent unit. It fits the 2S, 2TM, 5S, and 6T monitor lines, which share the same battery bay dimensions and voltage rail. Capacity comes directly from the original specification: 3000mAh / 11.1Wh.

• 2S / 2TM / 5S / 6T parent unit compatibility: These four Boifun models use the same 64.00 × 49.80 × 6.50mm cell with a 3.7V nominal rail and a matching connector footprint — the battery management system on each accepts the same charge profile and cutoff thresholds.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the parent unit's BMS. The protection circuit responded correctly to overvoltage, undervoltage, and short-circuit conditions. Cell voltage held within spec across full charge cycles.
• Re-pair the parent unit after installation: Boifun parent units drop their wireless link to the camera when internal power is fully interrupted. After fitting this battery, run the pairing sequence from the parent unit menu before testing range or night vision.

Parent unit not connecting to camera unit after battery swap

Boifun parent units store the paired camera address in volatile memory backed by the internal battery. When the cell is removed, that stored link clears. The unit boots with no camera registered and displays a searching or no signal screen. This is not a fault with the new battery — go to the parent unit settings menu, select "Pair Camera," and follow the on-screen steps to re-establish the link.

Parent unit battery draining overnight with screen active

Running the parent unit screen on full brightness through the night is a sustained high draw on a 3000mAh cell. The backlit LCD, audio circuit, and radio receiver running together pull significantly more current than the battery was sized to sustain indefinitely. Enable the screen timeout in the display settings — most Boifun models offer a 30-second or 1-minute auto-off option. The audio alert stays active with the screen off, so you will not miss a sound event.