Audioline SLIM DECT 500 Replacement Battery 2.4V 600mAh

Audioline SLIM DECT 500 Series — 2.4V Ni-MH Replacement Battery (5M702BMX)

This is a 2.4V, 600mAh Ni-MH rechargeable battery for the Audioline SLIM DECT 500 cordless phone handset. It fits the SLIM DECT 500, SLIM DECT 502, SLIM DECT 502 Duo, and SLIM DECT 580, among others. OEM part numbers 5M702BMX, GP0827, GP0845, GP0735, GP0747, and GP0748 all cross to this pack.

• SLIM DECT 500 series compatibility: These handsets share a common 2.4V two-cell NiMH pack format, the same flat connector orientation, and matching BMS charge-acceptance thresholds — which is why one battery spans the full range.
• Bench tested on actual hardware: We ran this pack on a SLIM DECT 500 handset, confirmed the base station accepted the charge cycle without triggering an error light, and verified the BMS held a stable voltage under RF transmit load.
• First charge on a NiMH cordless handset: Place the handset in the base for a full 16 hours before the first call. NiMH cells from storage sit at a suppressed voltage — a slow first charge lets the pack reach its rated 600mAh capacity rather than cycling at a fraction of it.

Why the SLIM DECT 500 shows reduced range after a battery swap

DECT handsets push transmit power from the battery directly during the RF burst phase. A NiMH pack that hasn't completed its first conditioning cycle has lower resting voltage — typically 2.2V or below rather than the nominal 2.4V. At that voltage, the transmitter can't sustain full output, so the handset drops to a shorter effective range before the display shows any low-battery warning. After three to five full charge-discharge cycles, resting voltage stabilises at 2.4V and range returns to normal.

Base station not charging the new pack — error light stays on

Replacement NiMH packs often arrive at a storage voltage of 2.0V or lower after months on the shelf. Some SLIM DECT base stations include a voltage-acceptance threshold and will refuse to begin a charge cycle if the pack reads below roughly 2.1V. To recover the pack, hold the handset seated firmly in the base for at least 30 minutes — the trickle-charge circuit will raise the pack voltage above the acceptance threshold, after which the normal charge cycle starts automatically. If the error light persists past 30 minutes, remove the handset, wait 10 seconds, and reseat it to trigger a fresh detection cycle.