About this replacement
Motorola R7 / R7A — 7.4V Li-ion Replacement Battery (PMNN4807)
This 7.4V, 5000mAh Li-ion battery replaces the PMNN4807, PMNN4807A, PMNN4808, PMNN4809, PMNN4810, and related OEM packs for the Motorola R7 and R7A portable radios. It fits the same connector and BMS handshake profile as the original, so the radio accepts it without prompting an accessory error. At 37Wh, it sits at the top of the standard-capacity range for this platform.
- R7 and R7A platform fit: Both models share the same battery bay geometry, contact layout, and BMS communication protocol, which is why a single pack covers the pair. The connector seats in one orientation and the BMS negotiation happens within seconds of insertion.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge on an R7 body, monitoring BMS cutoff thresholds at both the low-voltage floor and the transmit-current spike. The protection circuit held within spec across repeated PTT events.
- R7 contact seating on first install: If the charger dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The R7 platform requires a clean contact cycle to complete the BMS handshake before charging begins.
Why the R7 cuts out mid-transmission on a new PMNN4807 pack
The R7's transmit current draw spikes sharply the moment PTT is pressed — far higher than the steady standby draw. A new cell shipped at storage voltage sits around 3.7V per cell, which is low enough that the BMS can interpret the transmit surge as an overcurrent event and momentarily cut output. This is not a faulty pack. Run two or three full charge cycles first, and the cells stabilise at full charge voltage before the radio goes into service. The cutout behaviour stops once the pack has been fully conditioned.
Bar indicator showing one fewer bar than expected after fitting a new pack
The R7 uses a voltage-threshold system to display battery bars — it reads cell voltage and maps it to a bar level, with no fuel gauge chip involved. A new pack at storage voltage reads lower than a fully charged pack, so the radio reports one or two fewer bars than expected on first insertion. This is not a capacity or cell problem. Charge the pack fully on the dock until the indicator goes green, then reinsert — the bar display will reflect the correct full-charge voltage.