About this replacement
Zonare One Smartcart / Z-Pak — 15.6V Ni-MH Replacement Battery (85031-00)
This 15.6V, 13000mAh Ni-MH battery replaces the OEM pack in the Zonare One Smartcart and Z-Pak mobile ultrasound systems. It slots into the same bay as the original and matches the voltage rail the BMS expects for power-on verification. Capacity figure comes from product data — 202.8Wh total energy.
- One Smartcart and Z-Pak platform fit: Both units share the same 15.6V architecture and battery bay dimensions. The BMS on each platform authenticates voltage and cell chemistry at boot, so matching the Ni-MH chemistry here is not optional — a Li-ion swap will trip a hard fault.
- Bench tested on actual hardware: We cycled this pack through a full charge-discharge sequence and monitored BMS handshake at each power-on event. The protection circuit engaged correctly at low-voltage cutoff, and the charge IC accepted the cell without triggering an unrecognised-battery fault.
- Post-installation self-test requirement: After fitting this battery, allow the Zonare to complete its full power-on self-test without interruption. The BMS runs a capacity verification routine at startup — cutting power mid-sequence writes a false battery fault to the event log that persists until the next clean, uninterrupted boot cycle.
Why the Zonare One Smartcart alarms low battery on a fully charged new pack
The Zonare BMS stores a learned capacity model from the previous OEM cell. When a new pack is installed, the firmware compares real-time voltage readings against that stored model and flags a mismatch as low battery — even at full charge. This is not a defective cell. The BMS needs one complete charge-discharge cycle to recalibrate its capacity estimate against the new cell's actual curve. Run the cart through one full cycle before clinical use and the alarm clears.
Zonare cart fails to power on after the replacement battery sat in storage
Ni-MH cells self-discharge during storage — typically losing 15–20% per month under normal conditions. If the pack voltage drops below the BMS recovery threshold (approximately 10.5V on a 15.6V Ni-MH pack), the protection circuit locks out power delivery entirely and the cart shows no response at the power button. Connect the OEM charger and leave it on charge for a minimum of four hours before attempting to power on. The charge IC applies a trickle recovery current at this voltage level before handing off to the main charge algorithm.