Innovaphone D81 EX Replacement Battery 3.7V 1100mAh

Innovaphone D81 EX — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1100mAh Li-ion battery for the Innovaphone D81 EX cordless DECT handset. It slots into the handset bay and restores power to the wireless voice unit. Capacity figures are taken directly from product data — 1100mAh, 4.07Wh.

• D81 EX handset fit: The D81 EX runs a single-cell Li-ion pack at 3.7V nominal. The BMS in this handset monitors cell voltage and reports charge state to the base station over the charging contacts. Physical dimensions are 73.60 × 43.50 × 11.00mm — the housing tolerances on the D81 EX are tight, so cell thickness matters.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the D81 EX base station. The BMS accepted the cell without fault flags, completed a full charge cycle, and the handset reported battery status correctly on the display.
• First-charge protocol for Li-ion DECT handsets: After installing, seat the handset in the base and leave it for a full uninterrupted charge cycle before first use. The D81 EX base delivers a trickle current in the final stage — interrupting that stage early leaves the cell at roughly 90% and the handset will report low battery sooner than expected.

Why the D81 EX shows a shorter talk window after a battery swap

The D81 EX calibrates its fuel gauge against the cell it shipped with. A new cell has a different internal resistance profile, so the gauge reads conservatively until it logs two or three full charge-discharge cycles. This is not a capacity defect — it is a recalibration lag. Run the handset to the low-battery warning, then charge fully for two to three consecutive cycles. The displayed battery level will stabilise once the handset has enough cycle data to map the new cell accurately.

Handset losing DECT pairing after battery replacement

Removing the battery cuts all power to the D81 EX handset, including the volatile memory holding the base station registration. Some D81 EX units drop their pairing when power is fully interrupted. If the handset shows "searching" or fails to find the base after reassembly, it needs to be re-registered. Place the handset in range of the base, enter the base station's registration menu, and follow the standard DECT pairing sequence — the default system PIN on Innovaphone bases is typically 0000.