About this replacement
Hytera BD500 Series — 7.4V Li-ion Replacement Battery (BL1506)
This 7.4V, 1500mAh Li-ion battery replaces the OEM BL1506 and BL2018 packs in the Hytera BD500, BD505, and BD555 portable digital radios. These radios are widely used in security, logistics, and emergency services where pack failure mid-shift is not an option. The battery fits the standard battery bay with no modification required.
- BD500 / BD505 / BD555 platform fit: All three models share the same 7.4V voltage rail, battery bay geometry, and BMS handshake protocol — which is why one pack covers the full series. The connector and contact strip are identical across the BD500 family.
- Bench tested on actual hardware: We cycled this pack on a BD505 under transmit load and monitored BMS response. The protection circuit tripped correctly at the overcurrent threshold and recovered cleanly when the load was removed. No false lockouts were recorded.
- First insertion — charger contact check: If the charger dock shows a fault LED on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. The BD500 charger requires a clean contact cycle to accept the new BMS handshake before it begins charging.
Why the BD500 cuts out mid-transmission on a fresh pack
When PTT is pressed, the BD500 draws a sharp current spike to power the RF output stage. If the BMS reads that spike as an overcurrent event, it trips and cuts power instantly — even on a new battery. This is a protection circuit response, not a faulty pack. The fix is to ensure the battery contacts are clean and fully seated so contact resistance stays low. A loose or dirty contact inflates the apparent current draw and triggers the BMS unnecessarily.
Bar indicator reads one bar lower than expected after fitting this pack
New Li-ion cells ship at storage voltage — typically around 3.7V per cell, not the 4.2V of a fully charged pack. The BD500 uses a simple voltage-threshold bar indicator, so a pack at storage voltage will read one or two bars short of full. This is not a capacity defect. Seat the pack in the charger and let it complete a full charge cycle — the bar indicator will reflect actual charge state once the cells reach their rated voltage.