About this replacement
Moonybaby MB55935BV-2T / Trust 50 — 3.7V Li-Polymer Replacement Battery (FT525068P)
This 3.7V 2000mAh Li-Polymer battery replaces the internal pack in the parent unit of the Moonybaby MB55935BV-2T, MB55935-2T, Trust 50, and Split 50 baby monitor systems. When the original cell degrades, the parent unit loses charge capacity and can no longer sustain overnight monitoring. This replacement restores the parent unit to its full operating charge cycle.
- MB55935 and Trust 50 parent unit fit: These models share the same parent unit housing, PCB connector pinout, and 3.7V single-cell Li-Polymer BMS. The FT525068P cell matches the 60.30 × 45.60 × 5.00mm cavity and mates directly to the existing JST-style connector without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the parent unit board. The BMS engaged protection correctly at low-voltage cutoff and accepted a full charge without thermal events or false fault flags.
- Post-swap wireless re-pair: When the parent unit loses power completely during a battery swap, it drops its wireless link to the camera unit. After fitting this battery, charge the parent unit first, then re-pair it to the camera following the channel-sync steps in your manual before placing it back on the bedside table.
Parent unit not connecting to camera after battery swap
Baby monitors store the wireless channel pairing in volatile memory on the parent unit. A full power loss during battery replacement clears that memory, so the units come back up unlinked. This is not a fault with the new battery. Charge the parent unit to at least 50% first, then hold the pairing button on the camera unit until the parent unit display confirms a link — typically indicated by the camera feed appearing on screen.
Range dropping after fitting a new battery
The MB55935 parent unit's radio transmit power is voltage-sensitive. If the battery is installed and used immediately without charging, the cell voltage sits near 3.5V — below the threshold where the radio operates at full output. This causes noticeably reduced range through walls before the unit is fully charged. Charge the parent unit to 4.2V (full charge, indicated by a solid charge LED) before using it in another room.