Areca ARC-6120BAT RAID Controller Replacement Battery 3.7V 1800mAh

Areca ARC-11xx / ARC-12xx / ARC-1680/1880 Series — 3.7V Li-ion Replacement Battery (ARC-6120BAT)

This 3.7V 1800mAh Li-ion cell replaces the backup power module on Areca RAID controllers across the ARC-11xx(ML), ARC-12xx(ML), ARC-12xx(4i/4x/8x), and ARC-1680/1880 (I/X/LP/IX) series. When mains power drops, this battery holds the controller's write cache long enough for a graceful flush to disk. Without a functioning cell, the controller falls back to write-through mode permanently and cache data is at risk.

• Cross-series fit — ARC-11xx through ARC-1880: Areca standardised on the ARC-6120BAT footprint across multiple controller generations. All listed models share the same 3.7V rail, connector pinout, and BMS handshake protocol, which is why one cell covers such a wide compatibility range.
• Bench tested on actual hardware: We cycled this cell under simulated cache-hold conditions and confirmed the BMS communicates state-of-charge correctly to the controller. The controller recognised the new cell and queued a learn cycle without manual intervention on the ARC-1880.
• Learn cycle initiation after swap: After fitting the new cell, initiate a battery learn cycle from your controller's management interface — StorCLI: storcli /cx bbu start learn, or via the Areca web GUI under Battery Information. The controller stays in write-through mode until the learn cycle completes and recalibrates the backup window estimate against the new cell's actual capacity.

RAID controller staying in write-through mode after battery swap

Swapping the cell does not automatically restore write-back mode. The controller holds write-through until it has a verified backup window figure from a completed learn cycle. On Areca controllers, the learn cycle runs a full discharge-and-charge sequence, which can take 24–72 hours depending on system load. Until that cycle finishes, write-back mode remains locked out regardless of how healthy the new cell is.

Management console showing a battery error days after installation

Areca controllers run their battery health assessment on a timed interval, not at boot — so the first scheduled test may not execute until 24–72 hours post-installation. If the console flags a battery error during that window, check whether the learn cycle has actually completed by reviewing the Battery Information page in the Areca web GUI. A "Charging" or "Learn" status means the assessment is still running, not that the cell is faulty. Wait for the cycle to finish before treating the error as a hardware fault.