Motorola R2 PMNN4598A Replacement Battery 7.4V 2600mAh

Motorola R2 — 7.4V Li-ion Replacement Battery (PMNN4598A / PMNN4600A)

This is a 7.4V, 2600mAh Li-ion battery for the Motorola R2 portable two-way radio. It replaces OEM part numbers PMNN4598A and PMNN4600A. The R2 is a compact land mobile radio used in security, construction, and public safety — a working battery is non-negotiable on shift.

• R2 platform fit: Both PMNN4598A and PMNN4600A share the same contact layout, connector keying, and BMS handshake protocol on the R2 chassis. Either part number slots into the same battery bay without modification.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on the R2 platform. The BMS accepted the dock handshake on first insertion, held the charge curve within spec, and applied correct overcurrent cutoff when transmit current spiked at PTT press.
• First-shift insertion tip: If your R2 charger dock shows a fault LED on the first insertion, pull the battery, wipe the gold contact strip with a dry cloth, and reseat it firmly. The R2 dock requires a clean contact cycle to complete the BMS handshake before charging begins.

Why the R2 cuts out mid-transmission on a new battery

When you press PTT, the R2 draws a sharp current spike to power the RF output stage. If the new pack is sitting at storage voltage — typically around 3.7V per cell — the BMS may interpret that spike as an overcurrent event and trip the protection circuit. This is not a faulty battery. Put the pack on charge until the dock shows full, then insert it into the radio. Transmit current spikes are handled cleanly once cells are at operating voltage above 3.8V per cell.

R2 showing one fewer bar than expected after fitting a new pack

The R2 uses a voltage-threshold bar indicator — it reads cell voltage directly and maps it to bars. A new pack shipped at storage voltage reads lower than a fully charged one, so the radio displays fewer bars even though the battery is not depleted. This is not a capacity fault or a mismatch. Charge the pack fully in the dock and the bar indicator will reflect actual charge state. Full charge rests the pack at approximately 8.4V across both cells.