Veins Accuvein AV400 Compatible Battery 3.7V 3100mAh

Veins Accuvein AV400 — 3.7V Li-ion Replacement Battery (ACCUAVBA400)

This 3.7V, 3100mAh Li-ion battery replaces the internal cell in the Accuvein AV400 handheld vein finder. The AV400 uses near-infrared projection to visualise subcutaneous veins, and its battery must deliver consistent output to maintain accurate imaging during clinical procedures. Swapping a degraded cell restores full operational availability without replacing the entire unit.

• AV400 platform compatibility: The AV400 uses a fixed 3.7V single-cell Li-ion architecture with a BMS that monitors cell voltage and temperature during operation. This replacement cell matches the OEM voltage rail and connector footprint, so the charge IC communicates with the BMS without a handshake error on first boot.
• Bench tested on actual hardware: We cycled this cell through charge, boot self-test, and active imaging load on an AV400 unit. The BMS accepted the cell on the first full charge cycle and reported accurate state-of-charge without triggering a false fault flag.
• Post-swap self-test protocol: After fitting this battery, let the AV400 complete its full power-on self-test without interrupting the sequence. The device runs a BMS verification routine at startup — cutting power mid-cycle causes a battery fault flag that persists until the next clean, full reboot.

Why the AV400 alarms low battery immediately after a confirmed full charge

The AV400's BMS stores a learned capacity profile from the OEM cell. When a new replacement cell is installed, the BMS has no reference data for the new cell's actual charge curve, so it applies a conservative threshold that can trigger a low-battery alarm even at a high state of charge. This resolves after one complete charge-discharge cycle, which allows the BMS to build an accurate profile for the new cell. Do not use the device clinically until that first full cycle is complete.

AV400 not completing boot sequence after battery sat in storage

Li-ion cells self-discharge during storage. If a replacement cell drops below approximately 2.5V before installation, the AV400's BMS will refuse to power the device — this is a protection cutoff, not a dead cell. Place the battery on charge immediately after unpacking and leave it connected for a full cycle before attempting to power on. Most BMS recovery circuits begin accepting current above 3.0V, so a short initial charge period is enough to clear the lockout.