Plantronics CT901HS Cordless Phone Compatible Battery 3.6V 700mAh

Plantronics CT901HS — 3.6V Ni-MH Replacement Battery

This 3.6V, 700mAh Ni-MH battery replaces the factory pack in the Plantronics CT901HS cordless headset. It restores charging capacity when the original cell can no longer hold a usable charge. The CT901HS is a DECT wireless headset used in office environments for hands-free calling.

• CT901HS fit: The CT901HS headset uses a compact 3-cell Ni-MH pack at 3.6V nominal. This battery matches that voltage rail and physical footprint, so the headset seats correctly in the base charging cradle without connector stress.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the bench. The cells accepted a full charge without thermal runaway and held stable voltage under the low RF transmit draw typical of DECT headsets.
• First charge on NiMH cordless headsets: After installing, place the CT901HS in its base cradle for a full 16-hour charge before first use. Ni-MH cells shipped in storage state need a slow initial charge to reach rated 700mAh capacity — a fast first cycle will leave the pack underformed for the first several uses.

Base station showing no charge light after fitting a new Ni-MH pack

Ni-MH batteries lose voltage during storage and can arrive below the threshold the CT901HS base uses to confirm a valid pack is seated. If the base sees a resting voltage too low, it may not initiate the charge cycle at all. Place the headset firmly in the cradle and leave it undisturbed — some bases need up to 30 minutes before the charge indicator activates on a deeply discharged cell. If the light still does not appear, check that the headset connector pins are clean and making full contact with the cradle contacts.

Talk time shorter than rated after replacement

A new Ni-MH cell does not deliver full rated capacity on the first cycle — this is normal cell chemistry, not a fault. Capacity builds over the first three to five full charge-discharge cycles as the crystalline structure in the cells reforms. Run the headset to low charge, return it to the base for a full 16-hour charge, and repeat. By cycle five, the pack should be delivering close to its rated 700mAh and noticeably longer talk time than cycle one.