Nortel C4010 Cordless Phone Replacement Battery 3.6V 700mAh

Nortel C4010 / C4020 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 700mAh Ni-MH replacement battery for the Nortel C4010 and C4020 cordless phone handsets. It slots into the handset battery compartment and restores power to the unit so it can operate wirelessly from the base station. Dimensions are 46.60 × 31.40 × 10.60mm — confirm these against your existing cell before ordering.

• C4010 and C4020 compatibility: Both models share the same handset platform, battery bay dimensions, and 3.6V NiMH charging circuit in the base station. One battery fits both.
• Bench tested on actual hardware: We cycled this cell through the base station's trickle-charge circuit. The NiMH pack accepted charge without triggering the base's fault indicator, and voltage settled at the expected 3.6V nominal across discharge.
• First-charge requirement for NiMH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells ship partially discharged. Skipping the slow initial charge means the pack never reaches rated 700mAh capacity — this is a chemistry behaviour, not a defect.

Talk time shorter than original battery after replacement

NiMH cells need three to five full charge-discharge cycles to reach rated capacity. On the first cycle, the pack may deliver noticeably less talk time than expected — that is normal. Each subsequent full discharge and slow recharge conditions the cells further. By cycle five, capacity should stabilise near the rated 700mAh. Run the handset until it drops the call, then return it to the base for a full 16-hour charge to complete each conditioning cycle properly.

Base station showing no charge or error light with new battery installed

NiMH batteries self-discharge during storage, and a deeply discharged pack can sit below the voltage threshold the base station uses to detect a valid battery. The base then withholds charge entirely or shows a fault light. Remove the handset, wait 30 seconds, and reseat it firmly — physical contact matters here. If the error persists, the pack voltage may be too low for the base to accept; some Nortel bases require the cell to be at or above roughly 3.0V before the charge circuit engages.