About this replacement
Hytera PD355 / PD365 Series — 3.7V Li-Polymer Replacement Battery (BL2009)
This is a 3.7V, 1300mAh Li-Polymer replacement for the Hytera BL2009 battery pack. It fits the PD355, PD365, PD375, and PF355LF compact two-way radios. Voltage and capacity match the original spec so the radio's bar indicator and BMS behave as expected from first insertion.
- PD355 / PD365 / PD375 platform fit: These models share the same battery bay dimensions, 3.7V supply rail, and BL2009 connector footprint. A single pack revision covers the full compact-body family without adapter hardware.
- Bench tested on actual hardware: We cycled this pack through full charge and PTT transmit loads on a PD355. The BMS held current within spec during sustained transmit bursts and did not trip the overcurrent threshold under normal keying patterns.
- Contact strip seating on first dock insertion: If the charger shows a fault LED when this pack is first inserted, remove the battery and wipe the gold contact strip with a dry cloth before reseating. The PD355 dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
Why the PD355 cuts out mid-transmission on a new BL2009
A new Li-Polymer cell ships at storage voltage — typically around 3.6–3.7V — not at a full 4.2V charge. When the radio keys up, transmit current spikes sharply. At storage voltage, the BMS may read that spike as an undervoltage condition and briefly cut the output. The fix is simple: charge the pack fully before the first shift. Once the cell reaches 4.2V, the same transmit surge sits well inside the BMS operating window.
Bar indicator stuck on two bars after a full charge cycle
The PD355 reads battery level using voltage thresholds, not a fuel gauge chip. A new cell that has only completed one shallow charge cycle may not have reached the voltage the radio maps to a full-bar reading. Run two complete charge-discharge cycles through normal use. After the second full charge, the resting cell voltage should sit close to 4.1–4.2V and the bar indicator will display correctly.