Motorola MBP11 Baby Monitor Replacement Battery BY1131 2.4V

Motorola MBP11 — 2.4V Ni-MH Replacement Battery (BY1131)

This is a 2.4V, 300mAh Ni-MH replacement battery for the Motorola MBP11 baby monitor parent unit. It uses OEM part number BY1131 and fits the portable handset directly. When the original cell degrades and the parent unit stops holding charge, this replaces it like-for-like.

• MBP11 parent unit fit: The MBP11 handset runs on a single Ni-MH cell at 2.4V. The BY1131 matches the voltage rail, physical footprint (30.60 × 21.50 × 10.80mm), and connector orientation the parent unit expects. No cell chemistry conversion — Ni-MH to Ni-MH throughout.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the MBP11 parent unit. The onboard charging circuit accepted the cell without issue and the BMS reached full charge without fault flags.
• First charge after fitting: Place the parent unit on its charging cradle immediately after fitting the new cell and leave it until the charge indicator clears. Ni-MH cells ship partially discharged — the monitor's low-voltage cutoff can trigger before the unit has had a chance to function if you skip this step.

Parent unit not connecting to the camera unit after battery swap

Replacing the battery in the MBP11 parent unit causes a full power interruption. That clears the active wireless link between the handset and the camera unit. The monitor does not automatically re-establish the connection on power-up — it waits for a manual pairing sequence. Hold the pair button on the camera unit, then initiate the scan from the parent unit menu. Once paired, the link persists through normal on/off cycles as long as the battery does not fully discharge again.

Range dropping or signal cutting out after fitting a new battery

The MBP11's radio transmitter draws from the same 2.4V cell that powers the display and speaker. At low state of charge, the voltage sags and the radio operates below its rated output — range shrinks noticeably before the low-battery warning appears. If range feels shorter than it was with the original battery, the new cell may not be fully charged yet. Put the parent unit back on the cradle and charge to full before testing range. A fully charged BY1131 at 2.4V restores the transmitter to rated power.