Retevis RT29 7.4V Replacement Battery FA9140A 3000mAh

Retevis RT29 / RT29D / RT29U — 7.4V Li-ion Replacement Battery (FA9140A)

The FA9140A is a 7.4V, 3000mAh Li-ion battery for the Retevis RT29, RT29D, and RT29U handheld transceivers. It slots into the same battery bay as the original pack and connects to the same charge contacts on the radio body. Capacity is sourced from product data: 3000mAh / 22.2Wh.

• RT29 / RT29D / RT29U platform fit: All three variants share the same battery bay geometry, contact pin layout, and 7.4V nominal voltage rail. The BMS in this pack is matched to that voltage profile, so the radio's charge circuit accepts it without triggering a fault state.
• Bench tested on actual hardware: We ran this pack through full charge-discharge cycles on an RT29 body. The BMS held cutoff correctly at low voltage, and transmit current spikes during PTT press did not trip overcurrent protection under normal keying patterns.
• First-insertion contact check: If the charging cradle LED blinks fault on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The RT29 charging dock requires a clean contact cycle to complete the BMS handshake before charging begins — a loose or dirty contact prevents acceptance even when the pack is fully functional.

Why the RT29 cuts out mid-transmission on a fresh FA9140A

The RT29 draws a sharp current spike the instant PTT is pressed to bring the RF stage up to transmit power. A new cell shipped at storage voltage — typically around 3.7–3.8V per cell — sits closer to the BMS low-voltage threshold than a fully charged pack does. If the cell voltage sags enough under that initial load spike, the BMS interprets it as a fault and cuts output. Charge the pack fully to 8.4V before the first transmission cycle. That gives the cells enough headroom to absorb the PTT surge without triggering BMS cutoff.

Bar indicator showing one fewer bar than expected after install

The RT29 uses a voltage-threshold bar indicator — each bar corresponds to a voltage band, not a fuel gauge calculation. A new pack at storage voltage reads lower than a pack fresh off the charger, so the radio may display one bar short immediately after insertion. This is not a fault with the cell. Seat the pack in the charging cradle until the LED goes solid green, then reinsert into the radio. The bar indicator should read full at 8.4V.