About this replacement
DeTeWe Integral D3 / OpenPhone 24 / OpenPhone 28 — 2.4V Ni-MH Replacement Battery (4.999.046.235)
This is a 2.4V, 600mAh Ni-MH replacement battery for the DeTeWe Integral D3, OpenPhone 24, and OpenPhone 28 cordless DECT handsets. It replaces OEM part number 4.999.046.235. The battery fits inside the handset and powers the phone during use away from the base station.
- Integral D3, OpenPhone 24, and OpenPhone 28 compatibility: These three handsets share the same 2.4V NiMH battery bay, connector orientation, and cell footprint — 52.47 x 40.55 x 8.71mm. The same pack works across all three because DeTeWe used a common handset chassis for this product family.
- Bench tested on actual hardware: We cycled this battery through charge and discharge on the OpenPhone 24 base station. The base accepted the pack without error lights, and the NiMH cells reached stable voltage within the first three conditioning cycles.
- First-charge protocol for NiMH handsets: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells shipped from storage are partially discharged — skipping this slow first charge will reduce the usable capacity you see in early cycles.
Talk time shorter than the original battery after replacement
NiMH cells do not deliver rated capacity on cycle one. The electrochemical structure needs three to five full charge-discharge cycles to reach 600mAh. If talk time feels short in the first week, that is normal — not a fault with the battery. Run the handset down fully, return it to the base for a complete charge, and repeat. By cycle five, capacity stabilises close to the rated figure.
Base station showing no charge or error light with new pack installed
NiMH batteries lose voltage during storage. If the resting voltage drops low enough, some DeTeWe base stations reject the pack and flag an error rather than starting a charge cycle. Remove the handset, wait 30 seconds, then reseat it firmly. If the error persists, check that the handset contacts and base contacts are clean — oxidation on either surface can read as an open circuit. A clean contact and firm seating usually brings the resting voltage above the base's acceptance threshold of around 2.0V, at which point charging begins normally.