Product Overview
The Allen-Bradley 1756-BA2 is a factory-sealed, two-pack of lithium memory backup batteries specifically engineered for the Allen-Bradley ControlLogix 5560 and 5561 series of programmable automation controllers (PACs) and processors. This product is not a single battery but a convenient bundle containing two identical, high-performance 1756-BA1A lithium battery modules. Its primary function is to provide continuous, redundant backup power to the controller’s volatile memory, ensuring the preservation of the user program, tag data values, and system configuration during a main power loss or when the controller is powered down for maintenance or transport. The Allen-Bradley 1756-BA2 bundle addresses the critical need for memory integrity in sophisticated automation systems, where the loss of a control program could result in extensive production downtime, costly recovery efforts, and potential safety concerns.Each battery within the 1756-BA2 pack is designed to plug directly into the dedicated battery holder on the front of a compatible ControlLogix processor. The dual-pack configuration is a strategic offering that supports a proactive maintenance philosophy. It allows a technician to replace both batteries simultaneously—one serving as the primary backup and the other as an immediately available spare stored on-site—or to implement a redundant, hot-swap battery configuration directly in the controller. Some ControlLogix processor models support the installation of two batteries; when the primary battery voltage drops below a threshold, the controller can automatically and seamlessly switch to the secondary battery, providing an extended backup window and a clear warning for scheduled replacement without risk of data loss. The value of the Allen-Bradley 1756-BA2 lies in its role as a consumable yet vital component for safeguarding the intellectual property and operational state of high-value control systems. By ensuring an uninterrupted power supply to the controller’s memory, it guarantees that complex processes can resume normal operation immediately after a power restoration, maintaining sequence integrity and production efficiency.
Technical Specifications
| Parameter Name | Parameter Value |
|---|---|
| Product Model | 1756-BA2 |
| Manufacturer | Allen-Bradley (Rockwell Automation) |
| Product Type | Dual-Pack Memory Backup Battery |
| Contents | 2 x 1756-BA1A Lithium Battery Modules |
| Battery Type | Lithium Thionyl Chloride (Li-SOCl₂), Non-rechargeable |
| Nominal Voltage per Battery | 3.6 Volts DC |
| Capacity per Battery | 1.2 Amp-hours (Ah) minimum |
| Expected Service Life per Battery | 2-3 years at 25°C (77°F) with controller powered |
| Operating Temperature Range | -40°C to 85°C (-40°F to 185°F) |
| Storage Temperature Range | -40°C to 60°C (-40°F to 140°F) |
| Compatible Controllers | ControlLogix 5560 Series (L6), 5561 Series (L7, L8) |
| Connector | Integrated plug for ControlLogix processor socket |
| Memory Retention Time | Varies by controller model and ambient temperature; typically months |
| Packaging | Factory-sealed retail package containing two individual batteries |
Main Features and Advantages
Redundancy and Extended Protection: The core advantage of the Allen-Bradley 1756-BA2 twin-pack is the ability to implement redundancy. For processors that support dual-battery installation, it enables a true hot-backup configuration. The controller monitors both batteries, and if the primary depletes, it automatically switches to the secondary without interruption. This provides an extended grace period for replacement and completely eliminates the risk of data loss due to a single battery failure. Even for single-battery controllers, having a second battery from the 1756-BA2 pack on the shelf as an immediate spare ensures a rapid response to a low-battery alarm, preventing the scramble to source a part during a critical period.
