About this replacement
Bang & Olufsen Beocom 4 — 2.4V Ni-MH Replacement Battery (CTP950)
This is a 2.4V, 700mAh Ni-MH replacement battery for the Bang & Olufsen Beocom 4 cordless telephone handset. It replaces OEM part number CTP950, fitting directly into the handset battery compartment. Voltage and cell chemistry match the original specification exactly.
- Beocom 4 handset fit: The Beocom 4 base station charges via a contact-based cradle that expects a 2.4V Ni-MH cell pack at a specific physical footprint — 45.25 x 21.00 x 10.70mm. This pack meets both requirements. The base charge circuit won't negotiate with Li-ion voltage profiles, so chemistry match here is not optional.
- Bench tested on actual hardware: We cycled this pack through the Beocom 4 base station charge circuit and confirmed the cell voltage climbs correctly through the trickle and full-charge phases. The base station showed no fault indication across all test cycles.
- First charge after installation: After fitting the new pack, seat the handset in the base and leave it for a full 16 hours before using it. Ni-MH cordless phone batteries arrive in partial charge from storage — a slow first charge allows all cells to reach rated capacity together and prevents early cell imbalance.
Talk time shorter than expected after battery swap
Ni-MH cells don't hit rated capacity on the first charge cycle — this is normal cell behaviour, not a fault with the pack. The Beocom 4 draws a steady current during a call, and a partially conditioned pack will sag voltage sooner than a fully cycled one. Run three to five full charge-and-use cycles through the base station before comparing talk time to the original battery. After conditioning, cell voltage at rest should sit above 2.3V on a full charge.
Base station charge light not activating on a new pack
A Ni-MH pack that has been in storage for several months can drop to a voltage low enough that the base station charge circuit won't recognise it as a valid battery. The Beocom 4 base uses a delta-V detection method — if the starting voltage is too flat, it sees no delta and stalls. Remove the handset, wait 30 seconds, and re-seat it firmly to trigger a fresh detection cycle. If the light still won't activate, check that the handset contacts and base cradle contacts are clean — a resistance across the contact point can prevent the circuit from reading the pack voltage correctly.