Maxon SP130 Replacement Battery 7.2V 2500mAh Ni-MH

Maxon SP130 / SP140 Series — 7.2V Ni-MH Replacement Battery (WWN-MPA1400)

This 7.2V, 2500mAh Ni-MH pack replaces the OEM batteries in the Maxon SP130, SP130U, SP140, and SP140U handheld transceivers. It uses the same connector and contact layout as the original, so it seats and charges in the existing dock without modification. Capacity is sourced from the product data: 2500mAh, 18Wh.

• SP130 and SP140 platform fit: Both the SP130 and SP140 lines share the same battery bay geometry, contact strip, and 7.2V nominal voltage rail. The BMS handshake on these transceivers is contact-voltage based — the dock reads pack presence through the same three-contact strip, so one replacement pack covers the full SP130/SP140 family.
• Bench tested on actual hardware: We cycled this pack through a full charge sequence on a Maxon dock and confirmed the BMS accepted the handshake without fault LED. Transmit-current draw during PTT was measured at the expected spike range for 7.2V Ni-MH in this form factor — the protection circuit held without tripping.
• First insertion on a cold dock: If the dock throws a fault LED on first insertion, wipe the gold contact strip on the battery with a dry cloth and reseat firmly. The Maxon dock requires a clean contact cycle to accept the new pack's BMS handshake before the charge sequence begins.

Why the SP130 cuts out mid-transmission on a freshly inserted pack

Ni-MH cells ship at a reduced storage voltage, typically 6.0–6.4V for a 7.2V pack. When the SP130 draws transmit current from a pack at that voltage, the internal resistance causes an immediate voltage sag. If the sag pulls the pack below the radio's low-voltage cutoff threshold, the radio kills RF output to protect the circuit. This is not a faulty pack — it is a pack that has not yet been through a full charge cycle. Charge to 100% before the first field shift and the cutout will not recur.

Bar indicator on the SP140 showing one fewer bar than expected after a full charge

The SP130 and SP140 series use a simple voltage-threshold bar indicator — each bar corresponds to a voltage window, not a capacity percentage. A new Ni-MH pack fresh off its first charge often rests at a surface voltage slightly below the peak, because Ni-MH cells need two to three charge-discharge cycles before they reach full electrochemical activation. Run one full discharge under normal use, then recharge completely. After that cycle the resting voltage will sit in the correct threshold window and the bar indicator will read as expected.