Lionelo Babyline 5.1 Replacement Battery 3.7V 750mAh

Lionelo Babyline 5.1 (3 Wires Version) — 3.7V Li-Polymer Replacement Battery (GSP503337)

This 3.7V 750mAh Li-Polymer battery replaces the GSP503337 cell inside the Lionelo Babyline 5.1 baby monitor (3 wires version). It fits the parent unit of this two-way audio monitoring system. Voltage and capacity match the original specification exactly.

• Babyline 5.1 (3 wires version) fit: The 3-wire connector on this battery carries power and battery-level signal to the parent unit's PCB. A 2-wire substitute will power the unit but the charge indicator will read incorrectly — only the 3-wire GSP503337 format keeps that circuit intact.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Babyline 5.1 parent unit. The BMS accepted the battery without fault codes, and the charge LED stepped through its normal low-medium-full sequence without stalling.
• Re-pair after installation: The Babyline 5.1 parent unit loses its wireless link to the baby unit when power is fully interrupted. After fitting this battery, press and hold the pairing button on both units until the connection indicator reappears — skipping this step leaves the monitor silent.

Parent unit battery draining overnight on the Babyline 5.1

Running the Babyline 5.1 parent unit through the night with the screen active draws continuous current from the 750mAh cell. At typical backlight brightness, the display alone accounts for a significant share of that draw. The unit has a screen timeout setting in its menu — activating it reduces overnight drain substantially. Set the timeout to its shortest available interval if the battery is not lasting a full night.

Night vision not working after battery replacement on the Babyline 5.1

The IR LEDs on the baby unit require the battery to be at sufficient voltage before the night vision circuit activates. If you fit a new battery and go straight to a dark-room test, the cell may not yet have enough charge to drive those LEDs at full output. Charge the parent unit to 100% before testing night vision. If the IR image is still dim or absent after a full charge, the fault is in the camera unit, not the battery.