Uniden BP-38 GMRS380 Replacement Battery 4.8V 600mAh

Uniden GMRS380 / GMR885 Series — 4.8V Ni-MH Replacement Battery (BP-38)

This is a 4.8V 600mAh Ni-MH battery pack for the Uniden GMRS380, GMR885, GMR1038, GMR1448, and over 38 additional Uniden GMRS handhelds. It replaces OEM part numbers BP-38, BP-39, BP-40, BT-1013, and BT-537. If your original pack holds less charge than it used to or no longer takes a full charge cycle, this is the direct replacement.

• GMRS380 and GMR series compatibility: These models share a common 4.8V four-cell Ni-MH pack format with the same physical footprint and connector orientation. The voltage rail and contact layout are identical across the group, so one pack covers all of them.
• Bench tested on actual hardware: We ran this pack through charge and transmit cycles on the GMRS380 platform. The BMS handled PTT transmit current spikes without tripping into protection mode, and charge acceptance was consistent from the first cycle.
• Contact strip care on first dock insertion: If the charger shows a fault or blink pattern on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat it firmly. Ni-MH packs shipped at storage voltage may sit below the dock's acceptance threshold until the contacts seat cleanly and the charger reads the pack correctly.

Why the GMRS380 cuts out or drops TX power when you press PTT on a new pack

Pressing PTT pulls a sharp current spike as the RF stage ramps up. On a Ni-MH pack that arrived at storage voltage — typically around 4.2–4.5V across four cells — this spike can sag the voltage enough to trigger the radio's low-voltage protection circuit. The result is a momentary cut-out or a drop to reduced transmit power, even though the pack is not faulty. Run two or three full charge-discharge cycles first. After that, resting voltage climbs above 4.8V and the sag under transmit load stays within the radio's operating window.

Bar indicator showing one fewer bar than expected after inserting a new BP-38

The GMRS380 uses a simple voltage-threshold bar display — each bar corresponds to a voltage band, not a tracked capacity percentage. A new pack at storage voltage reads in the lower band and shows one fewer bar than a freshly charged pack would. This is not a capacity fault. Charge the pack fully in the dock until the charger LED goes solid green, then check the indicator — it will show the correct level at full charge voltage of approximately 5.5–5.8V across the four-cell stack.