About this replacement
V Tech VM311 Series — 3.6V Ni-MH Replacement Battery (AAA100PS3)
This 3.6V, 1000mAh Ni-MH battery replaces the rechargeable cell in the V Tech VM311 baby monitor parent unit. It fits the VM311, VM311-13, VM311-2, and VM311-23 models. When the original cell no longer holds a charge, this replacement restores full operation to the parent receiver.
- VM311 parent unit fit: All VM311 variants share the same parent unit housing, connector pinout, and 3.6V NiMH charge circuit. The same OEM part number — AAA100PS3 — covers the entire range, so one cell fits all listed models without modification.
- Bench tested on actual hardware: We ran this cell through the VM311 charge circuit and confirmed the NiMH charge termination behaved correctly — the unit reached float voltage without overcharging, and the low-battery indicator cleared after a full cycle.
- First charge after installation: NiMH cells ship at partial charge. Place the parent unit on its charging cradle for a full uninterrupted charge before first use — the VM311's charge circuit needs this initial cycle to calibrate the low-battery threshold correctly.
Parent unit draining faster overnight than during the day
Night mode on the VM311 keeps the audio circuit active continuously, which is a sustained draw that the original aged cell often cannot support. A fresh 1000mAh NiMH cell handles this load, but only after it has completed at least one full charge cycle. If the unit still drains overnight after replacement, check whether the screen backlight timeout is enabled — leaving the display on adds a constant secondary load that compounds the drain on a 3.6V cell.
Parent unit showing reduced range immediately after battery swap
The VM311's 2.4GHz radio module draws more current at distance, and its transmit power is voltage-sensitive. A partially charged NiMH cell sits below the 3.6V nominal rail, which causes the radio to step down output power and shorten effective range. This is not a fault with the cell or the unit. Charge the parent unit fully — verified by the charge LED turning green — before testing range, then confirm the cell is sitting at or above 3.9V fully charged.