V Tech BT198555 Baby Monitor Replacement Battery 3.7V 1000mAh

V Tech VM342 / VM342-2 — 3.7V Li-ion Replacement Battery (BT198555 / BT298555)

This 3.7V, 1000mAh Li-ion battery replaces the OEM BT198555 and BT298555 cells in the V Tech VM342 and VM342-2 baby monitor parent units. It restores power to the parent unit so it can receive audio from the nursery transmitter. Capacity figures come from the product data — 3.7Wh total stored energy.

• VM342 and VM342-2 parent unit fit: Both monitor variants use the same 3.7V single-cell architecture, same connector, and the same BMS handshake threshold. One battery covers both units without modification.
• Bench tested on actual hardware: We ran this cell through charge cycles on a VM342 parent unit. The onboard BMS accepted charge without fault flags, voltage held at 3.7V nominal under the parent unit's radio and audio draw, and the protection circuit tripped correctly at low-cell thresholds.
• Re-pair after fitting: The VM342 parent unit drops its wireless link to the nursery unit when it loses power completely. After fitting this battery and powering on, hold the LINK button on both units until the connection indicator confirms pairing — the monitor will not receive audio until this step is done.

Why the VM342 parent unit drains overnight with screen on

The VM342 keeps its LCD backlight, radio receiver, and audio circuit active simultaneously during night monitoring. That combined draw is significantly higher than standby. A degraded original battery collapses under this sustained load well before morning. This replacement cell handles the load, but enabling the screen timeout in the monitor's display settings reduces draw during quiet periods and extends time between charges.

Parent unit showing low battery immediately after fitting a new cell

A new Li-ion cell shipped in storage state typically sits at 3.5V or below — below the threshold the VM342 firmware reads as "charged." The parent unit will flag low battery until the cell is brought up to full charge. Place the parent unit on its charging cradle for a full uninterrupted charge cycle before use. Once the cell reaches 4.1–4.2V, the low-battery indicator will clear and the unit will operate normally.