About this replacement
HYT TC-320 / TC-320U — 3.7V Li-ion Replacement Battery (BL1715)
This 3.7V, 1700mAh lithium-ion battery replaces the OEM BL1715 and BL1101 packs in the HYT TC-320 and TC-320U portable two-way radios. It matches the original connector, contact layout, and BMS handshake the TC-320 dock expects. Capacity is 1700mAh (6.29Wh) — identical to the factory specification.
- TC-320 and TC-320U shared platform: Both variants run the same 3.7V rail, use the same battery bay dimensions (54.70 × 34.00 × 10.70mm), and draw from the same BMS protocol. One battery fits both without modification or adapter.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on a TC-320 unit. The BMS initialised correctly on first dock insertion, accepted charge without fault LED, and delivered consistent voltage under PTT transmit load.
- First-insertion contact check: If the TC-320 dock shows a fault LED on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. The TC-320 charger requires a clean contact cycle to complete the BMS handshake before it begins charging.
Why the TC-320 cuts out mid-transmission on a freshly inserted battery
A new cell ships at storage voltage — typically 3.6–3.7V — not at full charge. When you press PTT, the transmit circuit draws a sharp current spike. If cell voltage is near the lower storage threshold, the BMS reads that spike as an overcurrent event and trips the output. The radio cuts out instantly, then recovers when you release PTT. One full charge cycle before first use brings the cell to 4.2V and eliminates this behaviour entirely.
Bar indicator showing one fewer bar than expected after a full charge
The TC-320 uses a simple voltage-threshold bar indicator — it reads cell voltage directly and maps it to bar segments. A new cell straight off the charger can sit at 4.18–4.19V rather than the full 4.20V if the dock terminates charge slightly early on a new pack. That small gap drops the reading by one threshold step. Run one full discharge and recharge cycle and the bar indicator will settle at the correct level on subsequent charges.