Audioline BT-C250 Cordless Phone Replacement Battery 3.6V 700mAh

Audioline 5015 / CP60 Series — 3.6V Ni-MH Replacement Battery (BT-C250)

This is a 3.6V, 700mAh Ni-MH replacement battery for the Audioline 5015, 70, 71, and CP60 cordless phone handsets. It replaces the original BT-C250 pack that powers the handset during cordless operation. Fit the replacement, seat the handset in the base, and the phone charges as normal.

• Audioline 5015, 70, 71, CP60 compatibility: These models share the same 3.6V single-cell NiMH voltage rail, connector pinout, and physical footprint. The BT-C250 part number covers the entire group — one battery, same swap procedure across all of them.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the bench. The NiMH cells accepted a full charge from a standard DECT base station charge circuit without triggering the negative delta-V cutoff prematurely. Voltage held steady at 3.6V nominal throughout the test cycle.
• First charge after install: After fitting the battery, place the handset in the base and leave it for a full 16 hours before making a call. NiMH cells in cordless phones need a slow, full first charge to reach their rated 700mAh capacity — pulling the handset off early shortens the effective charge the cells accept.

Talk time shorter than the original battery after replacement

NiMH cells ship in a partially discharged state and often deliver below-rated capacity for the first three to five full cycles. This is a chemistry characteristic, not a fault with the cell. Each full charge-and-discharge cycle conditions the NiMH plates and gradually brings the battery up to its rated 700mAh. By cycle five, capacity should reach its working level — if it does not, check the base station contacts are clean and making firm contact with the handset.

Base station charge light not activating after fitting new battery

A NiMH pack sitting in storage drops to a low resting voltage — sometimes below the threshold the DECT base station uses to detect a valid battery and begin charging. The base sees the low voltage as an absent or faulty cell and withholds the charge current. To recover: hold the battery contacts against a known 3.6V NiMH charger for 10–15 minutes to bring voltage above 3.0V, then seat the handset in the Audioline base normally. The charge indicator should activate once the pack crosses that acceptance threshold.