Relm RPU416 BPRP1100 Replacement Battery 7.2V 2000mAh

Relm RPU416 / RPU499 / RPU516 Series — 7.2V Ni-MH Replacement Battery (BPRP1100)

This is a 7.2V, 2000mAh Ni-MH replacement battery for the Relm RPU416, RPU416A, RPU499, and RPU516 portable two-way radios. It matches OEM part numbers BPRP1100, BPRP1500, and BPRP1500MH. Drop it in where the original pack failed — same voltage rail, same connector footprint.

• RPU416 / RPU499 / RPU516 platform fit: These models share the same battery bay geometry, contact arrangement, and 7.2V charging profile. One pack covers the full RPU series listed because the BMS handshake and charge-termination logic are identical across them.
• Bench tested on actual hardware: We cycled this pack through full charge and transmit-load discharge on the RPU platform. The BMS handled the PTT current spike without tripping, and delta-V cutoff triggered cleanly at end of charge with no overrun.
• First insertion into the dock: If the charger shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The RPU dock requires a clean contact cycle to register the new pack before it starts the charge sequence.

Why the RPU416 cuts out mid-transmission on a freshly inserted pack

Ni-MH cells ship at storage voltage — typically 1.0–1.1V per cell, which puts a six-cell pack around 6.2–6.6V. The RPU416's radio module draws a sharp current surge the moment PTT is pressed. At storage voltage, internal resistance is higher, so voltage sags under that load and the radio's undervoltage protection trips the output stage. This isn't a faulty pack — it's a cell that needs one full charge cycle before it can hold the voltage rail steady under transmit current. Run the pack through a complete charge before putting it into service.

Bar indicator showing one fewer bar than expected after charging

The RPU series uses fixed voltage-threshold bar indicators — each bar maps to a voltage band, not a percentage. A new Ni-MH pack that hasn't completed its first conditioning cycle often rests at a voltage that sits just below a threshold, so the indicator drops one bar even after a full charge. This resolves after one or two full charge-discharge cycles as the cells reach their rated capacity. After two cycles, check resting voltage is at or above 7.2V before drawing conclusions about pack health.