Moonybaby MB55935BV-2T Replacement Battery 3.7V 1200mAh

Moonybaby MB55935BV-2T Series — 3.7V Li-Polymer Replacement Battery (AHB503759)

This is a 3.7V, 1200mAh lithium-polymer replacement battery for the Moonybaby MB55935BV-2T parent unit. OEM part number AHB503759. It also fits the MB55935-2T, Split 55, and MB55935 parent units that share the same cell footprint and connector.

• MB55935 series parent unit fit: These models share the same 3.7V single-cell architecture, connector pinout, and BMS handshake. The AHB503759 cell is 60.30 × 36.80 × 5.00mm — a flat Li-Polymer pouch that sits flush in the parent unit housing without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the MB55935BV-2T parent unit. The BMS accepted the cell without fault codes, held the 3.7V nominal rail cleanly, and the unit powered through both audio and video transmission without voltage drop.
• Wireless re-pair after swap: When the parent unit loses power completely, it drops its wireless link to the camera unit. After fitting this battery and powering on, hold the pairing button on both units until the signal icon re-locks — the monitor will not display a feed until that step is done.

Parent unit not connecting to camera unit after battery swap

Baby monitors store their wireless pairing state in volatile memory on the parent unit. A full power loss — like a dead or removed battery — wipes that state. When you fit the new AHB503759 cell and power on, the parent unit boots as if it has never seen the camera. Put the parent unit within one metre of the camera unit, then press and hold the pairing button on the camera until the LED flashes, then confirm on the parent unit. Once paired, normal operating range returns.

Night vision drops out on the camera unit after fitting a new battery

The IR LEDs that power night vision draw a sharp current spike when they activate, and the parent unit's radio link needs a stable voltage rail to keep the feed alive through that spike. If the new cell is not fully charged, the BMS can't support the combined IR and radio load, and the image cuts to static or goes dark. Charge the parent unit to 100% before the first overnight session — at full charge, the 3.7V rail holds firm through IR LED activation and the night vision feed stays locked.