About this replacement
EADS THR8 — 3.7V Li-ion Replacement Battery (BLN-7)
This is a 3.7V, 2200mAh Li-ion replacement battery for the EADS THR8 handheld two-way radio. It uses OEM part number BLN-7 and fits the THR8 directly. Voltage and cell format match the original pack specification.
- THR8 platform fit: The THR8 uses a single-cell 3.7V Li-ion pack with a proprietary contact layout and BMS handshake. This replacement matches that voltage rail and connector geometry so the radio's protection circuit recognises the pack on first insertion.
- Bench tested on actual hardware: We cycled this pack through charge, standby, and simulated PTT transmit loads. The BMS handled the transmit current spike without tripping into lockout, and the protection circuit re-engaged cleanly after each discharge cycle.
- First-insertion contact check on the THR8 charger dock: If the dock shows a fault LED on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. The THR8 charger requires a clean contact cycle to complete the BMS handshake before it begins charging.
THR8 bar indicator reading lower than expected on a new BLN-7
New Li-ion cells ship at storage voltage — typically around 3.6V to 3.7V, not a full 4.2V charge. The THR8 maps its bar indicator directly to voltage thresholds, so a pack at storage voltage will show fewer bars than a fully charged one. This is not a fault with the cell. A full charge cycle in the dock will bring the pack to 4.2V and the indicator will reflect that correctly.
THR8 cutting out mid-transmission on a replacement BLN-7
Pressing PTT draws significantly more current than standby — the transmit load on a 3.7V single-cell pack can spike sharply enough to trigger the BMS overcurrent cutoff if the cell is partially discharged. The radio cuts out because the BMS interrupts the circuit to protect the cell, not because the pack has failed. Fully charge the battery before use and avoid transmitting at high power on a pack below roughly 3.8V resting voltage. If cutouts persist on a full charge, check the dock contacts for corrosion and re-seat the pack.