Tytera TC-720S Replacement Battery BL1718 7.4V 1800mAh

Tytera TC-720S / TC3000G / TC700G — 7.4V Li-ion Replacement Battery (BL1718)

This is a 7.4V, 1800mAh Li-ion battery pack built to the BL1718 specification. It fits the Tytera TC-720S, TC3000G, and TC700G two-way radios. The cell chemistry and BMS parameters match the OEM pack so the charger dock and radio accept it without modification.

• TC-720S, TC3000G, and TC700G compatibility: All three models share the same 7.4V nominal rail, BL1718 connector footprint, and BMS handshake protocol — which is why one pack covers the entire group. Swapping between units requires no hardware change.
• Bench tested on actual hardware: We cycled this pack through PTT transmit loads on the TC-720S platform. The BMS held voltage steady through repeated transmit bursts and tripped cleanly at the low-voltage cutoff threshold without requiring a manual reset.
• First insertion into the charger dock: If the dock LED flashes fault on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly. The TC-720S platform requires a clean contact cycle to complete the BMS handshake before charging begins.

Why the TC-720S drops to reduced TX power mid-shift on a new BL1718

A new Li-ion cell ships at storage voltage — typically around 3.7V per cell, which puts a two-cell pack near 7.4V open-circuit. Under sustained RF output, that voltage sags below the radio's minimum TX threshold faster than a fully charged pack would. The TC-720S firmware responds by stepping down transmit power to protect the final stage amplifier. This is not a faulty pack — it is the radio responding correctly to a cell that has not yet been through a full charge cycle. Charge the pack to 8.4V (full) before the first shift and the sag behaviour disappears.

Bar indicator shows one fewer bar than expected after fitting BL1718

The TC-720S uses voltage-threshold bar indicators, not a fuel gauge chip. A freshly shipped pack sitting at storage voltage reads one threshold lower than a fully charged pack, so the display shows one bar short even though the cell is healthy. This is not a capacity defect. Put the pack through one full charge cycle in the dock until the LED goes green, then power the radio on — the bar count will reflect the correct charge state at 8.4V.