V Tech 3N600AACL Replacement Battery 3.6V 1200mAh Ni-MH

V Tech 3N600AACL / NP600 / B650 / 9125 — 3.6V Ni-MH Replacement Battery

This is a 3.6V, 1200mAh Ni-MH rechargeable battery for V Tech cordless phone handsets. It fits the 3N600AACL, NP600, B650, and 9125 models. These models share the same cell format, voltage rail, and contact configuration at the handset battery bay.

• 3N600AACL / NP600 / B650 / 9125 compatibility: All four models use the same 3.6V three-cell Ni-MH pack with identical physical footprint and polarity layout. The base station charging circuit in each model targets the same float voltage, so the battery seats and charges the same way across the range.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the bench. The BMS accepted charge from the base station without error, and voltage held stable across standby and active talk draws. No thermal cutoff events occurred during testing.
• First-charge conditioning on NiMH cordless packs: After installing, seat the handset in the base for a full 16-hour charge before first use. Ni-MH cells in cordless phone packs ship in a partially discharged state. Skipping the slow initial charge leaves cells unevenly conditioned, which reduces usable capacity from the first cycle onward.

Talk time shorter than original battery after the first few charges

Ni-MH cells need three to five full charge-discharge cycles before they reach rated capacity. On cycle one, a fresh pack may deliver noticeably less talk time than the original. This is a chemistry behaviour, not a defect. By cycle four or five, capacity stabilises at or near the rated 1200mAh.

Base station shows no charge or error light after battery swap

Ni-MH packs sitting in warehouse storage can drop below the voltage threshold that the V Tech base station's charging circuit needs to initiate a charge cycle. The base reads the pack as absent or faulty and shows an error light instead of charging. To recover, remove the handset, hold the power button for five seconds to drain residual charge in the handset circuit, then reseat and leave it docked for at least 30 minutes. If the base still does not respond, the pack voltage is likely below 2.8V and may need a brief boost charge from an external Ni-MH charger before the base will accept it.