Ativa D5702 Cordless Phone Replacement Battery 3.6V 700mAh

Ativa D5702 / D5772 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 700mAh Ni-MH battery for Ativa cordless phone handsets. It fits the D5702, D5772, D-5702, and D-5772 models. Swap it in when the original pack no longer holds enough charge to get through a day of calls.

• D5702 and D5772 handset compatibility: Both models run the same 3.6V single-cell NiMH pack with an identical connector footprint and cell arrangement. The voltage rail and physical dimensions are shared across the D5702 and D5772 handset chassis, so one battery covers all four model variants listed.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on NiMH-rated test equipment. The BMS accepted full charge without cutoff errors, and cell voltage held steady across discharge at normal cordless phone standby and talk draw.
• First-charge protocol for NiMH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells shipped in partial-charge storage need a slow, uninterrupted initial charge to reach rated 700mAh capacity — a quick top-up will not do it.

Talk time shorter than expected after the first few charges

NiMH batteries do not ship at full capacity. Fresh cells need three to five full charge-discharge cycles before they reach rated capacity. If talk time feels short after the first charge, that is normal — not a fault with the cell. Run the handset until it signals low battery, then return it to the base for a full charge. By cycle four or five, capacity should be at or close to the rated 700mAh.

Base station shows no charge or error light after battery swap

A new NiMH pack stored at low voltage can fall below the threshold some Ativa base stations use to confirm a valid battery is present. The base reads the incoming voltage, and if it is too low, it stops the charge circuit rather than risk a fault. Place the handset in the base and wait — most units will begin trickle charging within a few minutes once the cell voltage climbs above roughly 3.0V. If the error light clears after 15 to 30 minutes and the charge indicator appears, the battery is accepting current normally.