About this replacement
GRACO M13B8720-000 Parent Unit — 4.8V Ni-MH Replacement Battery (BATT-M13B)
This 4.8V 700mAh Ni-MH battery replaces the original rechargeable cell in the GRACO M and M13B8720-000 baby monitor parent unit. It restores power to the handheld unit you carry while the camera stays at the crib. Voltage and capacity match the OEM spec exactly — no modifications needed.
- M and M13B8720-000 parent unit fit: Both models use the same 4.8V Ni-MH pack with identical connector pinout and cell count. The parent unit's charging circuit expects this exact voltage rail — substituting a different chemistry or voltage causes incorrect charge termination.
- Bench tested on actual hardware: We cycled this pack through the parent unit's onboard charger and confirmed the charge termination triggered correctly at full capacity. The BMS accepted the cell without fault flags on the display.
- Wireless re-pair after swap: When the parent unit loses power completely — as it will during a battery swap — it drops its wireless link to the camera unit. Once the new battery is installed and the unit powers on, run the pairing sequence in the monitor menu before expecting video or audio.
Parent unit battery draining overnight on the M monitor
The M parent unit keeps its screen active and maintains a constant radio link to the camera — both draw continuous current through the night. Ni-MH cells also self-discharge faster than lithium chemistry, so a partially charged pack loses measurable capacity even at idle. Enable the screen timeout function in the monitor's display settings to cut the screen draw between checks. A fully charged new pack combined with screen timeout will give you noticeably longer overnight use compared to a degraded original cell.
Night vision not working after fitting a new battery
The camera unit's IR LEDs pull more current than standard daytime operation, and the parent unit's radio must maintain a stable link to receive that feed. If the new battery was installed with a partial charge, the voltage may sit low enough that the system de-prioritises the IR channel. Charge the parent unit fully before testing night vision — on a fresh Ni-MH pack this typically means leaving it on the dock until the charge indicator clears. Once at full voltage, trigger night mode manually by covering the camera's ambient light sensor to confirm the IR LEDs activate.