About this replacement
Hytera HYT-S1 Series — 3.85V Li-ion Replacement Battery (P2200)
This 3.85V, 2200mAh Li-ion battery replaces the Hytera P2200 pack used in the HYT-S1, HYT-S1 Pro, HYT-S31, and HYT-S35 portable radios. These are slim digital portables used across security, public safety, and commercial comms — the battery slot and BMS handshake protocol are shared across all four models. Capacity figures come from the product specification, not the original Hytera pack label.
- HYT-S1 series compatibility: The HYT-S1, HYT-S1 Pro, HYT-S31, and HYT-S35 all use the same slim form factor, share the same contact pin layout, and expect the same BMS initialisation sequence — which is why a single replacement pack covers all four variants.
- Bench tested on actual hardware: We ran this pack through full charge cycles and PTT-triggered load bursts on the HYT-S1 platform. The BMS handled transmit current spikes without tripping into protection mode, and the cell voltage held steady across repeated keying events.
- First insertion into the charger dock: If the dock shows a fault LED on first insertion, remove the pack, wipe the gold contact strip with a dry cloth, and reseat firmly — the HYT-S1 charger requires a clean contact cycle to accept the new BMS before charging begins.
Why the HYT-S1 cuts out mid-transmission on a fresh battery
The HYT-S1 draws a sharp current spike the moment PTT is pressed — RF output demands significantly more current than standby mode. If a replacement pack ships at storage voltage (around 3.6–3.7V), the BMS can interpret the transmit surge as an overcurrent event and trip protection before the radio completes a single transmission. This is not a faulty pack. Charge the battery fully in the dock before first field use — a cell at full charge handles the transmit spike without triggering BMS cutoff.
Bar indicator showing one fewer bar than expected on a new P2200
The HYT-S1 reads battery level by measuring cell voltage against fixed thresholds — it has no counters or adaptive circuitry. A new cell delivered at storage voltage (approximately 3.6V) sits below the top-bar threshold, so the radio displays three bars instead of four. This is storage voltage, not reduced capacity. Place the pack in the charger dock until the charge indicator goes green — cell voltage will rise to 4.2V and the radio will display a full indicator on the next power cycle.