Tidradio TD-M8 Replacement Battery 3.7V 1100mAh Li-ion

Tidradio TD-M8 — 3.7V Li-ion Replacement Battery

This 3.7V, 1100mAh Li-ion battery replaces the original pack in the Tidradio TD-M8 portable two-way radio. It fits the TD-M8 transceiver directly, restoring transmit and standby power when the original cell has degraded. Capacity is 1100mAh (4.07Wh) as supplied.

• TD-M8 fit: The TD-M8 runs a single-cell 3.7V Li-ion architecture. This pack matches that voltage rail and the physical form factor — 53.00 × 33.90 × 5.70mm — so the battery seats flush and the BMS communicates correctly with the radio's charge circuit.
• Bench tested on actual hardware: We cycled this pack through full charge, held-PTT transmit loads, and idle standby draws. The BMS held cutoff thresholds at both ends of the discharge curve without tripping prematurely under the transmit current spike.
• First insertion on the TD-M8 charger: If the charger shows a fault LED on first dock, remove the battery, wipe the contact pads with a dry cloth, and reseat firmly. The TD-M8 charger requires a clean contact cycle to complete the initial BMS handshake before it begins charging.

Why the TD-M8 cuts out mid-transmission on a new battery

A new Li-ion cell ships at storage voltage — typically around 3.6–3.7V, not a full 4.2V charge. When you key PTT, transmit current spikes sharply and the BMS sees the cell voltage dip below its overcurrent threshold. The radio cuts the transmit circuit to protect the cell. Fully charge the pack before your first transmission session and the BMS will no longer trip on that initial spike.

TD-M8 bar indicator showing one fewer bar than expected on a fresh pack

The TD-M8 reads cell voltage directly and maps it to a bar indicator — it has no fuel gauge chip. A pack at storage voltage (around 3.65V) will show one bar short of full, even though the cell is healthy. This is not a fault with the battery. Charge the pack fully to 4.2V and the indicator will step up to the correct level.