ZKTeco YT105050 Replacement Battery 3.7V 3000mAh Li-Polymer

ZKTeco ZK-255 / AQD-V43-W — 3.7V Li-Polymer Replacement Battery (YT105050)

This is a 3.7V 3000mAh Li-Polymer replacement battery for the ZKTeco ZK-255 and the Multifunctional Air Quality Detector AQD-V43-W. It uses OEM part number YT105050 and matches the original cell footprint at 49.60 × 49.50 × 9.70mm. If your instrument is shutting down in the field or no longer holding charge, this pack replaces the original cell directly.

• ZK-255 and AQD-V43-W compatibility: Both devices run the same 3.7V single-cell architecture with identical connector pinout and BMS handshake protocol. The YT105050 part number covers both units — the air quality detector and the ZK-255 share the same battery bay and protection circuit interface.
• Bench tested on actual hardware: We cycled this pack under sensor-active load conditions and monitored BMS response during probe initialisation. The protection circuit handled the brief current spike at sensor power-up without triggering a false cutoff, and the cell voltage remained stable across a sustained logging session.
• First-use calibration on the ZK-255: After installing this pack, run a full calibration cycle through the instrument menu before field deployment. The ZK-255 maps battery state during calibration — skipping this step causes premature low-battery warnings during your first measurement session even when the pack is fully charged.

ZK-255 shutting down mid-measurement with battery showing charged

The ZK-255 draws a brief current spike each time the sensor array initialises or a new probe module powers up. If the cell's internal resistance has climbed — common in aged Li-Polymer packs — that spike pulls the terminal voltage below the BMS cutoff threshold for a fraction of a second. The instrument interprets this as a dead battery and shuts off even if the state of charge reads high. A fresh cell with lower internal resistance keeps the voltage rail stable through those transient loads and prevents nuisance shutdowns.

Pack will not charge after the instrument sat unused for months

Li-Polymer cells self-discharge over time. If the ZK-255 sat in a case for several months, the pack may have dropped below 2.5V — the threshold where most BMS circuits lock out to prevent cell damage. The charger sees the lock and stops, so the instrument shows no charging activity. Connect the device to a charger and leave it for 45–60 minutes without interruption; some BMS circuits re-initialise through a trickle-charge recovery cycle once voltage climbs back above 2.8V. If the pack still does not respond, the original cell is below recovery voltage and needs replacement.