Tenovis DECT MM588 Compatible Battery 3.7V 950mAh

Tenovis DECT MM588 — 3.7V Li-ion Replacement Battery (4.998.020.274)

This 3.7V, 950mAh lithium-ion battery replaces the OEM pack in the Tenovis DECT MM588 cordless handset. It matches the original cell's voltage and physical footprint, covering both the DECT MM588 and MM588 variants. Dimensions are 61.28 × 50.19 × 10.21mm — measure your existing pack before ordering if you are unsure.

• MM588 handset compatibility: Both listed model variants — DECT MM588 and MM588 — share the same battery bay, connector orientation, and 3.7V supply rail. No modification is needed for either.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the MM588 platform. The protection circuit responded correctly to overcharge and over-discharge cutoff thresholds, and the base station accepted charge handshake without error.
• First-charge protocol for Li-ion cordless handsets: Place the MM588 in its base cradle immediately after installing this battery and leave it undisturbed for a full charge cycle before making calls. Li-ion cells shipped in storage state need one uninterrupted charge to calibrate the protection circuit's reported capacity accurately.

Talk time shorter than the original battery after replacement

A new Li-ion cell often reports lower capacity on the first one or two cycles because the protection circuit has not yet mapped the cell's full voltage range. The base station's charge termination logic cuts off based on voltage slope, and a cold cell fresh from storage compresses that slope. Run two to three full charge-discharge cycles through normal use and the reported and actual capacity will align. If talk time is still noticeably short after five cycles, check that the handset contacts are clean — oxidised pins add resistance that triggers early low-battery cutoff.

Base station showing no-charge or error light after battery swap

When a Li-ion cell arrives below approximately 2.5V from extended storage, some DECT base stations refuse to initiate a charge cycle — the base interprets the low voltage as a fault rather than a depleted pack. Place the handset in the cradle, leave it for 20 minutes without lifting it, then check the charge indicator again. Most MM588 base units will begin trickling current once the cell climbs above the acceptance threshold. If the error persists, confirm the cradle contacts are making firm contact with the handset — a misaligned pack seat is the other common cause.