About this replacement
AT&T WF720 — 3.6V Ni-MH Replacement Battery (Ni3615T30P3S534416)
This is a 3.6V, 2000mAh Ni-MH battery for the AT&T WF720 cordless phone handset. It replaces the original pack when the handset stops holding a charge or dies faster than it used to. Direct physical and electrical match to the WF720 battery bay.
- WF720 handset fit: The WF720 runs on a single-cell Ni-MH pack at 3.6V nominal. The base station charges at a rate matched to that voltage range. Swapping to a pack outside that spec causes charging faults or no-charge indication at the base.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on a WF720-compatible test rig. The BMS accepted charge from the base without triggering an error state, and voltage held steady under simulated talk-load draw.
- First charge on the WF720: After installing, seat the handset in the base and leave it for a full 16 hours before first use. Ni-MH cells shipped in storage discharge to a low state — a slow first charge lets the pack reach rated 2000mAh capacity instead of cycling at a fraction of it.
Base station showing no charge light after installing a new Ni-MH pack
Ni-MH packs lose voltage during storage. If the pack voltage drops low enough, the WF720 base station may not recognise it as a valid battery and won't initiate a charge cycle. This is a threshold issue in the base's charge controller, not a fault with the pack itself. Placing the handset firmly in the cradle and leaving it for 30–60 minutes often allows the base to detect a slow rise in voltage and kick in. If the charge light still doesn't appear, remove and reseat the handset to reset the contact signal.
Talk time shorter than expected after the first few cycles
Ni-MH cells don't hit rated capacity on the first charge — or the second. The WF720's new battery will typically perform below its 2000mAh ceiling for the first three to five full charge and discharge cycles as the cells condition. Each full cycle builds usable capacity incrementally. Run the handset down to low battery indication, then charge fully in the base — repeat this three to five times and talk time will stabilise at the rated level.