Grundig Calios 1 Replacement Battery 3.7V 600mAh Li-ion RP423048

Grundig Calios 1 Series — 3.7V Li-ion Replacement Battery (RP423048)

This is a 3.7V, 600mAh Li-ion replacement battery for the Grundig Calios 1, Calios 1A, and Calios H1 cordless DECT handsets. It replaces OEM part numbers RP423048, LZ423048BT, CP76, and LZ423048. Dimensions are 50.00 x 30.50 x 4.20mm — check these against your existing cell before ordering.

• Calios 1, 1A, and H1 compatibility: All three handsets share the same battery bay geometry, connector orientation, and 3.7V nominal voltage rail. The BMS handshake on each model accepts the same charge termination signal, so a single cell covers the full range.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Calios 1 handset. The BMS accepted charge from the base station without triggering an error state, and voltage held steady at 3.7V nominal through the discharge curve.
• First-charge protocol for Li-ion DECT handsets: Place the handset in the base immediately after fitting the new cell and leave it for a full uninterrupted charge cycle before first use. Li-ion cells shipped in partial-charge storage states can report inaccurate capacity to the handset until the BMS completes one full calibration cycle.

Talk time shorter than the original battery after replacement

A new Li-ion cell often shows reduced talk time for the first two to three cycles. This happens because the cell ships in a low state of charge and the BMS has not yet calibrated its capacity estimate against a full charge-discharge cycle. The handset's fuel gauge reads from BMS data, not direct voltage — so it can cut off early before the cell is actually depleted. Run two or three full charge and discharge cycles and the reported capacity will align with the rated 600mAh.

Handset not pairing with base after battery swap

Some DECT handsets store pairing data in volatile memory that resets when power is fully removed — which happens every time the battery is pulled. If the Calios 1 handset shows no link to the base after the swap, the pairing registration has been lost. Go to the base station, press and hold the registration button until the LED flashes, then trigger the handset's locate or register function from its menu. Pairing completes once the handset confirms a four-digit PIN, typically 0000 by default on Grundig DECT bases.