About this replacement
Yaesu FT-3D / VX-8R Series — 7.4V Li-ion Replacement Battery (SBR-14)
This 7.4V, 3300mAh lithium-ion battery replaces the SBR-14 and FNB-102LI packs used in the Yaesu FT-3D, FT-8DR, VX-8R, and VX-8DR handheld transceivers. It fits the same battery bay and uses the same connector and BMS handshake as the factory pack. Voltage and capacity match the OEM spec exactly — 7.4V nominal, 24.42Wh.
- FT-3D, FT-8DR, VX-8R, VX-8DR shared platform: These models share the same battery bay geometry, contact strip layout, and BMS communication protocol. One pack covers all four radios because Yaesu standardised the voltage rail and connector across this generation of dual-band handhelds.
- Bench tested on actual hardware: We cycled this pack through PTT transmit bursts on the FT-3D platform. The BMS handled the transmit current spike without tripping into overcurrent lockout, and the charger dock accepted the pack and moved through its charge stages normally.
- First insertion on the dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The Yaesu dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
Why the FT-3D drops to reduced TX power mid-transmission on a new pack
New lithium-ion cells ship at storage voltage — typically 3.6–3.7V per cell, not the 4.2V full-charge peak. At storage voltage, the pack cannot sustain the current draw of a sustained high-power transmission without the terminal voltage sagging below the radio's TX threshold. The FT-3D firmware interprets this sag as a low-battery condition and steps the transmit power down automatically. A full charge cycle before field use brings both cells to 4.2V and eliminates the sag. Once fully charged, the pack handles continuous TX output at rated power.
Bar indicator showing one fewer bar than expected after inserting a new SBR-14
The FT-3D uses a voltage-threshold bar indicator — it reads resting terminal voltage and maps it to a bar count. A new pack at storage voltage sits below the threshold for a full display, so the radio shows one or two bars even though the pack is not depleted. This is not a fault with the pack or the radio. Charge the battery fully in the dock until the charge LED goes green, then reinsert it — the indicator will reflect the correct charge state at 8.4V (full charge, both cells at 4.2V).