About this replacement
Motorola R7 / R7A — 7.4V Li-ion Replacement Battery (PMNN4807)
This 7.4V, 3350mAh Li-ion battery replaces the PMNN4807 series packs used in the Motorola R7 and R7A portable two-way radios. It fits the standard battery bay on both variants without modification. Capacity figures come from product data — 24.79Wh total energy storage.
- R7 and R7A platform fit: Both models share the same battery bay geometry, contact rail layout, and BMS handshake protocol. A single pack covers both variants because Motorola kept the electrical interface consistent across the R7 series, including units with and without the keypad module.
- Bench tested on actual hardware: We cycled this pack through transmit-load sequences on an R7 dock. The BMS held the voltage rail steady through repeated PTT events and did not trip under the inrush current that fires when the radio keys up at full RF output.
- First insertion into the R7 charger dock: If the dock LED flashes amber or red on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The R7 charging system requires a clean contact cycle to complete the BMS handshake before the charge cycle begins.
Why the R7 drops to reduced TX power mid-shift on a new battery
A new Li-ion cell ships at storage voltage — typically 3.6–3.7V per cell, not the 4.2V peak of a full charge. Under sustained RF output, the R7's power amplifier draws hard on that headroom. When cell voltage sags below the radio's internal threshold, the firmware steps TX power down rather than cutting out entirely. This is normal protection behaviour, not a faulty pack. Charge the battery fully in the dock before the first shift — a complete charge cycle brings both cells to 4.2V and eliminates the sag margin issue.
R7 bar indicator showing one fewer bar than expected on a fresh pack
The R7 reads battery level from cell voltage alone — it uses voltage-threshold steps, not a fuel gauge chip. A new pack at storage voltage sits in the lower threshold band, so the radio reports one or two bars even though the pack is not depleted. After a full charge in the PMNN4807-compatible dock, cell voltage rises to approximately 8.4V across the pack and the indicator moves to the correct full-charge display. If the indicator still reads low after a completed charge cycle, check that the dock contacts are clean and that the charge light reached solid green before removing the pack.