Vodafone H20 Cordless Phone Compatible Battery 3.6V 400mAh

Vodafone H20 — 3.6V Ni-MH Replacement Battery (4M3EMJZ)

This is a 3.6V, 400mAh Ni-MH replacement battery for the Vodafone H20 cordless DECT handset. It fits directly into the handset battery bay and restores wireless communication within range of the base station. Capacity matches the original specification — 400mAh, 1.44Wh.

• H20 handset fit: The H20 uses a compact Ni-MH cell at 3.6V to match the handset's charging circuit and BMS acceptance threshold. The physical dimensions — 48.30 x 33.41 x 6.65mm — and connector orientation align with the original battery bay without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the bench. The BMS handshake with a base station charging circuit accepted the cell without error, and voltage held stable across typical DECT transmit load.
• First charge on a NiMH cordless pack: After installing, seat the handset in the base and leave it for a full 16 hours before first use. NiMH cells shipped from storage have a reduced initial charge state — a slow first charge lets the pack reach its rated 400mAh capacity properly.

Base station charge light not activating on a new NiMH pack

A NiMH cell that has sat in storage can drop below the voltage floor the base station uses to detect a valid battery. Some Vodafone base stations refuse to begin a charge cycle if the incoming voltage reads too low, which shows as no charge light or an error indicator. The fix is to briefly power on the handset — even just the display — which draws enough current to confirm battery presence. After that, re-seat the handset in the base; the charging circuit should then accept the pack and begin charging normally from around 3.2V upward.

Talk time shorter than expected after fitting replacement battery

Short talk time on a new NiMH pack is normal for the first three to five charge cycles. NiMH chemistry requires conditioning — each full charge and discharge cycle allows more of the cell's active material to participate, gradually building toward the rated 400mAh. If talk time is still noticeably short after five full cycles, confirm the handset is reaching a full charge by leaving it in the base for at least 16 hours per session. By cycle five, resting voltage after a full charge should sit at approximately 4.2–4.5V across the three-cell pack.