Avaya DH6 Replacement Battery BKB201010/1 3.7V 650mAh

Avaya DH6 / DECT 3730 / DECT 3720 — 3.7V Li-ion Replacement Battery (BKB201010/1)

This is a 3.7V Li-ion replacement battery rated at 650mAh (2.41Wh) for the Avaya DH6, DECT 3730, and DECT 3720 cordless phone handsets. It matches OEM part numbers BKB201010/1, FA01302005, FA83601195, 660177 R1A, 660177 R1D, and 660177 1F. Fits directly into the handset battery compartment with no modification.

• DH6, DECT 3730 and DECT 3720 compatibility: These three handset models share the same 3.7V single-cell Li-ion architecture, battery form factor (47 × 34 × 4.60mm), and connector pinout. The BMS handshake is identical across all three — one battery covers the full range.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the DH6 handset platform. The BMS responded correctly to charge termination and low-voltage cutoff, and the handset showed a full charge indicator within a normal charge window.
• First-charge protocol for Li-ion cordless handsets: After installing, seat the handset in its base and leave it undisturbed for a full charge cycle before use. Li-ion cells shipped in storage mode often report falsely low capacity on the first cycle — a complete charge from rest lets the BMS recalibrate its state-of-charge reading accurately.

Talk time shorter than the original battery after fitting this replacement

A freshly installed Li-ion cell often delivers noticeably less talk time on the first one or two cycles. This happens because the cell ships in a partially discharged storage state, and the BMS hasn't yet built an accurate charge profile for it. Run two or three full charge-to-discharge cycles and capacity will stabilise at the rated 650mAh. If talk time is still short after five cycles, check that the handset contacts and battery terminals are clean and making firm contact.

Handset not pairing with base station after battery swap

Removing a battery from a DECT handset cuts power completely, and some Avaya DECT models drop their pairing data when power is lost. This isn't a battery fault — it's the handset losing its stored registration with the base. Re-pair the handset using the subscription procedure in the base station menu, which typically involves holding the registration button on the base for three seconds until the handset detects it. Once paired, the handset will hold registration through subsequent battery swaps as long as the new battery retains a charge above 3.0V.