Nortel MC901 Cordless Phone Replacement Battery 3.6V 700mAh

Nortel MC901 — 3.6V Ni-MH Replacement Battery

This is a 3.6V 700mAh Ni-MH replacement battery for the Nortel MC901 cordless phone handset. It slots into the handset battery compartment and powers both talk and standby functions. No OEM part number is published for this pack — the MC901 model match is the confirmed identifier.

• MC901 handset fit: The MC901 runs a standard 3.6V single-cell Ni-MH pack at this form factor — 45 × 36 × 10mm. That voltage rail matches the base station charge circuit, and the connector seats directly into the handset's battery bay without modification.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a Ni-MH test rig. The BMS held charge acceptance across repeated cycles, and cell voltage climbed to the expected 4.2–4.3V peak under slow charge — consistent with a healthy 3.6V Ni-MH pack at 700mAh rated capacity.
• First-charge conditioning on the MC901: After installing, seat the handset in the base and leave it for a full 16 hours before first use. Ni-MH cells shipped in storage state need a slow first charge to reach rated capacity — skipping this step is the single most common cause of short talk time reports on new replacement packs.

Talk time shorter than expected after fitting a new pack

Ni-MH cells do not deliver full capacity from cycle one. The electrochemical structure needs three to five full charge-discharge cycles before the active material is fully utilised. On the MC901, this means the first few calls may feel shorter than the original battery — that is normal cell behaviour, not a fault. By cycle four or five, rated capacity stabilises and talk time reaches its full level.

Base station charge light not activating on a freshly installed pack

When a Ni-MH pack sits in storage, its resting voltage drops — sometimes below the threshold the MC901 base station uses to confirm a battery is present before beginning a charge cycle. The base interprets a very flat pack as an absent or faulty battery and holds the charge light off. To recover, remove the handset, wait ten seconds, and reseat it firmly — this resets the base charge controller detection cycle. If the light still does not activate, check that the handset contacts are clean and making full contact with the cradle pins.