Accuvein AV400 Replacement Battery 3.7V 3100mAh

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 visualization device. It fits directly in the AV400 unit used in clinical settings for vascular imaging during blood draws and IV placement. OEM part numbers ACCUAVBA400, BA400, and MAP3724-BAT all cross-reference to this cell.

• AV400 platform fit: The AV400 uses a single 3.7V Li-ion cell with a BMS that authenticates charge state at startup. This replacement matches the voltage rail and connector configuration the device expects — no modification needed at the cell level.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the AV400 platform. The onboard BMS accepted the cell without fault flags after the first full charge cycle completed. Charge IC behaviour matched OEM cell baseline.
• Post-swap self-test protocol: After fitting this battery, allow the AV400 to complete its full power-on self-test without interrupting the boot sequence. The device BMS runs a verification pass at startup — cutting power during this window logs a false battery fault that persists until the next full reboot.

AV400 displaying low battery alarm immediately after a confirmed full charge

The AV400's BMS applies a charge-state threshold calibrated to the OEM cell's discharge curve. A new replacement cell has not yet run a full charge-discharge cycle, so the BMS reads its state-of-charge conservatively and may trigger the low battery alarm even when the cell is fully charged. This is not a cell fault. Run one complete charge cycle — charge to full, use the device until it powers down on its own, then recharge to 100%. After that first cycle, the BMS correctly maps the replacement cell's curve and the alarm clears.

AV400 will not power on after the replacement cell sat in storage

Li-ion cells self-discharge during storage. If a replacement cell drops below approximately 2.5V, the AV400's BMS will refuse to initialise — the protection circuit blocks load connection to prevent damage to an over-discharged cell. The fix is a slow pre-charge: place the battery in the AV400 on charge and leave it connected for a full charge cycle without attempting to power the device on. Most BMS circuits will allow trickle current to recover the cell once it crosses the 2.8–3.0V threshold, at which point normal charging resumes.