About this replacement
HelloBaby Dragon Touch E40 / HB24 Series — 3.7V Li-Polymer Replacement Battery (BAT-UU24)
This is a 3.7V, 1000mAh Li-Polymer battery for the HelloBaby Dragon Touch E40, HB24, HB24RX, and HB32 baby monitor parent units. It replaces OEM part BAT-UU24 and restores portable operation to the parent unit. The original battery in these monitors degrades with regular charge cycles, leaving the parent unit tethered to the wall.
- HB24 and E40 series compatibility: These models share the same parent unit chassis, BAT-UU24 connector pinout, and 3.7V power rail — all confirmed against the physical unit before listing.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the HB24 parent unit. The BMS accepted the battery without error flags, and voltage held within spec across full charge and idle draw.
- Re-pair after swap: After fitting a new battery, the parent unit loses its stored wireless link to the camera unit. Power both units on, then hold the pair button on the camera until the parent unit confirms the connection — this is normal behaviour after any full power loss.
Parent unit range drop after battery replacement
The HB24 and E40 parent units use a 2.4GHz radio module that draws from the same 3.7V cell as the display and audio circuits. When a new or partially charged battery is installed, the radio transmits at reduced power until the cell reaches full charge voltage — around 4.2V. A fresh battery fitted straight out of the packaging will often show noticeably shorter range for the first hour of use. Charge the parent unit fully before testing range.
Night vision not working after fitting a new battery
The IR LEDs in the camera unit are unaffected by the parent unit battery — but the parent unit's IR receive circuitry and display brightness both depend on stable voltage. If the parent unit screen shows a dark or washed-out night vision feed immediately after a battery swap, the cell voltage is likely still below 3.9V. Do not test night vision on a battery that has just been installed. Charge to full first, then switch the room lights off and confirm the feed.