Allen-Bradley 1747-BA SLC Lithium Battery — Specs & Buying Guide

By Abdullah Zahid
15 min read
Allen-Bradley 1747-BA SLC Lithium Battery assembly with FDK CR14250SE cell and plug-in connector for SLC 500 CPU memory backup

Allen-Bradley 1747-BA SLC Lithium Battery: Specs, Compatibility, and Buying Guide for SLC 500 Systems

If you are a maintenance engineer or MRO buyer finalizing a spare-parts order for an SLC 500 installation, the Allen-Bradley 1747-BA SLC Lithium Battery is likely already on your list — the question is whether you have the right catalog number, the right quantity, and a reliable source before your next shutdown window. The 1747-BA is a non-rechargeable lithium metal battery assembly using an FDK CR14250SE cell at approximately 3.0 VDC, supplied with pre-attached wire leads and a plug-in connector sized for compatible SLC 500 CPUs. It serves one critical role: keeping CPU RAM and real-time clock data alive when main control power is removed, preventing program loss and unplanned recovery costs.

If you have already confirmed the 1747-BA is the correct battery for your SLC 500 controller, check current pricing and availability at LeadTime.ca — we ship worldwide.

Who Should Buy the 1747-BA — and Who Shouldn't

The Allen-Bradley 1747-BA is the right choice for facilities actively maintaining SLC 500 controllers where unplanned downtime or program loss carries significant operational cost. It is right for you if all of the following apply:

  • Your existing SLC 500 CPU documentation or user manual explicitly lists 1747-BA as the required backup battery — not a different Rockwell catalog number.
  • Your plant standards require OEM Allen-Bradley components for compliance, warranty coverage, or standardized maintenance records.
  • You need a direct plug-in replacement with the correct connector and lead length — no field wiring changes, no adapters.
  • You are planning preventive replacement during a scheduled shutdown or responding to a battery-low indication on an active SLC 500 rack.
  • You are building a critical-spares inventory across multiple SLC 500 controllers on one production line or across a facility.

If your controller is a ControlLogix, MicroLogix, or any non-SLC 500 family, the 1747-BA is not your battery — those systems use different Rockwell catalog numbers such as 1756-BA or 1763-BA. If you are launching a new project, investing in SLC 500 spares may not be the right long-term strategy; modern PLC families carry their own backup power solutions.

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What the Allen-Bradley 1747-BA Actually Does in an SLC 500 System

The 1747-BA SLC Lithium Battery is not a power supply component — it is a memory retention device. When the SLC 500 rack loses main control power, whether during a planned shutdown, a utility outage, or an emergency stop, the 1747-BA provides a low-current backup voltage that holds the CPU's RAM contents and real-time clock in place. Without it, an extended unpowered period results in lost program data, which means manual reload from backup before the line can restart. In plants with dozens of SLC 500 racks, the difference between a 15-minute battery swap and a multi-hour program recovery is entirely dependent on whether a fresh 1747-BA was installed on schedule.

Rockwell Automation's official product descriptor for this catalog number is simply "SLC Lithium Battery," which confirms its exclusive intended application within the SLC family. The battery assembly uses an FDK CR14250SE cell — a cylindrical 1/2 AA format — with a lithium content of approximately 0.29 g as documented in Rockwell's safety datasheet. The pre-attached leads and keyed connector mean installation is a plug-in operation requiring no field wiring to the cell itself, which keeps replacement time short and eliminates wiring errors during a live-swap procedure. Because it uses lithium metal chemistry, it is non-rechargeable and subject to lithium battery transport regulations — a sourcing consideration discussed below.

Typical System Architecture: Where the 1747-BA Sits in Your Control Panel

The 1747-BA connects directly inside the SLC 500 CPU module, between the controller's internal RAM circuit and the battery connector on the CPU board. It does not appear in the I/O rack signal chain — it is a maintenance component seated inside the processor itself.

  • Plant AC power feeds the SLC 500 power supply module, which powers the CPU and I/O racks during normal operation.
  • The SLC 500 CPU module contains onboard RAM holding the ladder logic program and real-time clock data.
  • The 1747-BA connects to the CPU's internal battery connector, providing backup voltage to RAM only when main power is absent.
  • A battery-low status bit and LED indicator on the CPU front panel signal when the 1747-BA voltage has dropped below threshold — prompting a scheduled replacement before program retention is at risk.
  • Downstream field devices, I/O modules, and communications cards are unaffected by the battery; they resume normal operation once main power is restored and the program remains intact.

Industries and Applications That Rely on the 1747-BA

The SLC 500 platform has been embedded in production environments for decades, and the 1747-BA supports that installed base across a wide range of industries. In food and beverage manufacturing, packaging lines built around SLC 500 racks depend on backup batteries to survive weekend shutdowns and seasonal changeovers without losing recipe parameters or sequencing logic. In automotive and metals plants, SLC 500 controllers managing press operations or conveyor systems may go through extended holiday shutdowns where a weak battery is the only thing standing between a clean restart and an emergency reprogram on a Monday morning.

Municipal water and wastewater facilities represent another significant application segment. These sites often run SLC 500 controllers in remote pump stations where power interruptions are not uncommon and maintenance teams may only visit on a scheduled cycle — making proactive battery replacement and on-site sparing essential. OEM machinery builders who shipped equipment with SLC 500 controllers also continue to support the 1747-BA as a field-replaceable maintenance item for their end users worldwide.

The common thread across all these deployments is the cost asymmetry: the 1747-BA is a low-cost consumable item relative to the downtime or reprogramming labor cost if it fails at the wrong moment. Plants with five or more SLC 500 racks typically stock 1747-BA batteries as a standard critical spare alongside fuses and power supply modules.

Application Typical Deployment
Food and beverage packaging line Multiple SLC 500 racks; batteries replaced on annual or biennial PM schedule during line changeover shutdowns
Automotive assembly or stamping SLC 500 controllers on press or transfer equipment; batteries stocked on-site for immediate swap during holiday shutdowns
Municipal water/wastewater pump station Remote SLC 500 installations; proactive replacement during routine service visits to prevent program loss between visits
Legacy OEM machinery Field replacement by service technician; 1747-BA stocked in service kit alongside common SLC 500 spare modules
Material handling and warehousing SLC 500 sorter and conveyor controls; batteries replaced during facility maintenance windows to maintain program integrity
Process industry (metals, chemicals) Critical SLC 500 loop controllers; OEM battery required by plant standards; spares held in instrument crib

Key Specifications for Purchase Decisions

Parameter Value Notes
Manufacturer Allen-Bradley (Rockwell Automation) OEM battery assembly for designated SLC 500 controllers
Catalog Number 1747-BA Must match CPU documentation before ordering
Official Product Name SLC Lithium Battery Rockwell Automation official product descriptor
Chemistry Lithium metal, non-rechargeable Per Rockwell lithium battery safety documentation
Cell Type FDK CR14250SE Stated in Rockwell Automation documentation for 1747-BA
Nominal Voltage Approximately 3.0 VDC Based on FDK CR14250SE cell; distributor-sourced technical data
Typical Capacity Approximately 850 mAh Distributor-sourced; for indicative life planning only
Lithium Content Approximately 0.29 g From Rockwell safety datasheet; relevant for transport classification
Form Factor Cylindrical 1/2 AA cell with wire leads and plug-in connector Enclosed assembly; no field wiring to cell required
Country of Origin Japan Based on Rockwell and distributor product data

Full technical specifications are available on the product page at LeadTime.ca.

1747-BA vs. Other Rockwell Batteries: Choosing the Right Catalog Number

One of the most frequent ordering errors in SLC 500 maintenance is specifying the wrong Rockwell lithium battery. The table below compares the 1747-BA with the most commonly confused alternatives. None of the other catalog numbers listed below are drop-in replacements for the 1747-BA — connector style, lead length, and intended controller family differ between them.

Catalog Number Intended Controller Family Direct Replacement for 1747-BA? Key Distinction
1747-BA Allen-Bradley SLC 500 (selected CPUs) N/A — this is the reference part FDK CR14250SE cell; approx. 3.0 VDC; 1/2 AA with leads and connector
1756-BA Allen-Bradley ControlLogix No Different connector and form factor for ControlLogix CPUs; not compatible with SLC 500
1763-BA Allen-Bradley MicroLogix 1100 No Specific to MicroLogix 1100 battery slot; different housing and connector
Third-party 1747-BA equivalents SLC 500 (claimed compatible) Only if connector, chemistry, and lead length are verified Lower cost; variable quality; connector and chemistry must be confirmed before use

If your controller documentation specifies 1747-BA, that is the only catalog number that eliminates compatibility risk without additional verification. For third-party equivalents, confirm connector style, lead length, lithium chemistry, and approximate capacity against the OEM specification before bulk ordering. Check current 1747-BA availability at LeadTime.ca — ships worldwide.

Expert Verdict: Is the OEM 1747-BA Worth the Premium?

The Allen-Bradley 1747-BA is a textbook case where the OEM part earns its price. For any facility with multiple SLC 500 racks still central to production, the genuine Rockwell battery eliminates every compatibility question before it becomes a maintenance headache. The FDK CR14250SE cell, the correct connector, the pre-attached leads, the approximately 850 mAh capacity, and the Rockwell one-year warranty are all known quantities. When a technician pulls the wrong battery from the tool crib at 2 AM during an emergency swap, the consequence of a connector mismatch or early failure from an unvetted third-party cell is measured in hours of downtime — not the price difference between OEM and aftermarket. The 1747-BA makes sense for maintenance teams that have standardized on OEM spares for SLC 500, for operations where program loss is catastrophic, and for facilities where the installed SLC 500 base justifies a deliberate stocking and replacement interval strategy.

The case for looking at alternatives is also real. If you operate a single low-criticality SLC 500 controller and your plant standards permit third-party components, a reputable aftermarket equivalent with a verified connector match and lithium metal chemistry is a legitimate option — provided you test it in a non-critical system first and document the substitution. If you are evaluating new capital projects or considering a platform migration, the better investment may be in a modern PLC family rather than deepening SLC 500 spare inventory. The 1747-BA is not an argument for keeping aging hardware running past its useful life; it is the right maintenance call for assets that are still earning their place on the production floor.

From a procurement standpoint, the lithium content of approximately 0.29 g means the 1747-BA is subject to lithium battery transport regulations that can add hazmat fees or restrict air freight options — factors that affect lead time and landed cost depending on your location. Sourcing through a specialist automation distributor who understands SLC 500 variants, manages lithium shipping compliance, and can confirm compatibility against your specific CPU catalog numbers before the order ships removes that uncertainty entirely. View current pricing and availability for the 1747-BA at LeadTime.ca — we stock and ship industrial automation components worldwide.

For volume pricing, stocking agreements, or to confirm lead time before committing to a maintenance budget, contact the LeadTime.ca team directly — we ship worldwide and can assist with lithium battery shipping requirements for your region.

What Engineers Are Saying About the 1747-BA

Across PLC forums including PLCTalk, PLCS.net, MrPLC, Reddit's r/PLC and r/automation communities, and distributor Q&A threads, the recurring verdict on the 1747-BA is consistent: it works reliably, it fits correctly, and the OEM connector eliminates guesswork during a tight shutdown window. Maintenance technicians frequently cite the direct plug-in connector as the detail that makes emergency replacements fast and confident — there is no lead trimming, no connector adaptation, and no uncertainty about whether the cell chemistry matches what the CPU expects. Many teams report that the 1747-BA has provided many years of reliable service in SLC 500 systems when installed and stored correctly, and that using the official Rockwell battery consistently reduces troubleshooting time because compatibility is never in question.

The most persistent complaint in the community is cost. The OEM 1747-BA carries a price premium over third-party replacements, and in plants with a large SLC 500 installed base, that premium multiplies quickly across a spare-parts budget. This frustration has driven a segment of buyers toward aftermarket equivalents — but community threads are full of cautions about the results: wrong connectors, shortened lead lengths, and in some cases early failure that triggered the exact program-loss event the battery was meant to prevent. The other recurring warning is part-number confusion. The 1747-BA, 1756-BA, and 1763-BA look similar in catalog listings, and multiple technicians have documented receiving the wrong battery after ordering by memory rather than by cross-checking the CPU manual. Wrong orders from distributors stocking all three variants are a real and avoidable cost.

Community members also flag a scenario that catches even experienced teams: replacing the battery with the controller powered down and no current program backup on file. The SLC 500's RAM content is retained by the battery during unpowered periods — remove both simultaneously and the program is gone. This mistake appears repeatedly in troubleshooting threads where a technician replaced the battery during an outage, restored power, and found the CPU in a faulted or default state. The community consensus is unambiguous: always have a current offline backup before any battery work, and where possible, follow the controller manual's guidance on replacing the battery with power applied to maintain RAM continuity.

Installation and Replacement: What to Know Before You Start

Battery replacement on the SLC 500 is a low-complexity task when properly prepared, but the consequences of doing it wrong are significant. The following overview covers the key points; always refer to the specific SLC 500 CPU user manual and Rockwell's lithium battery handling instructions for complete procedures.

  • Confirm a current and verified offline program backup exists before touching the battery — program loss during a battery swap without a backup is the most consequential mistake in SLC 500 maintenance.
  • Follow controller manual guidance on powered vs. unpowered replacement; SLC 500 manuals generally recommend replacing the 1747-BA with the rack powered to maintain RAM continuity during the connector swap.
  • Disconnect the old battery by grasping the connector body, not by pulling the wire leads; re-route the new 1747-BA leads to match the original path so they do not interfere with the CPU door or adjacent modules.
  • Verify the new connector is fully seated before closing the CPU access cover; a partially seated connector can cause intermittent RAM retention and may not immediately trigger a battery-low indicator.
  • After replacement, confirm that any battery-low status bits or LED indicators have cleared, document the replacement date on the battery label or in the plant maintenance system, and monitor the controller over the next operating shift for stable operation.

Wrong-Part Prevention Checklist Before You Order

Before submitting a purchase order for the 1747-BA, work through each item below. This checklist is drawn directly from common ordering errors and the wrong-part patterns documented in this brief.

  1. Verify the PLC family is SLC 500 and that the CPU or chassis documentation explicitly specifies 1747-BA as the backup battery.
  2. Confirm you are not confusing 1747-BA with other Rockwell batteries (e.g., 1756-BA, 1763-BA) used in different controller families.
  3. Check connector style and lead length against the existing battery assembly before bulk ordering.
  4. Review controller firmware or user manual for any specific battery replacement instructions and supported part numbers.
  5. Confirm regional shipping rules for lithium batteries and whether your project can accept ground-transport-only lead times.
  6. Check required quantity for both installed units and critical spares to avoid partial coverage of a production line.

If any item on this checklist raises a question you cannot resolve from your controller documentation, contact the LeadTime.ca team before ordering — confirming compatibility against your specific SLC 500 CPU catalog number takes minutes and prevents a costly wrong-part return.

Frequently Asked Questions

How often should I replace the 1747-BA even if no battery-low warning has appeared?

There is no single universal interval published by Rockwell for all SLC 500 installations, as service life depends on operating temperature, backup duty cycle, and cell storage history. Community practice in manufacturing environments is to establish a fixed preventive replacement interval — commonly every few years — based on the plant's experience and the criticality of each SLC 500 rack. Do not rely solely on the battery-low indicator as the trigger; by the time the indicator appears, available backup capacity is already reduced. Check the Rockwell CPU manual for any guidance specific to your controller model and consult your distributor if you need help setting a stocking and replacement schedule.

Can I replace the 1747-BA with the SLC 500 controller powered off?

The SLC 500 CPU manuals generally recommend replacing the 1747-BA with control power applied to the rack, which keeps the RAM energized from the main power supply during the connector swap and prevents program loss. Replacing the battery with power off is possible only if you have a current, verified offline program backup and are prepared to reload the program after power restoration. Removing both main power and the battery simultaneously without a backup is the most common cause of accidental program loss during battery maintenance — this scenario appears repeatedly in community troubleshooting discussions.

What are the risks of using a third-party replacement instead of the OEM 1747-BA?

Third-party batteries marketed as 1747-BA equivalents vary significantly in quality, connector precision, and cell chemistry consistency. The primary risks are an incorrect connector that does not fully seat in the SLC 500 CPU battery socket, shortened lead length that creates installation difficulty, and cells with lower actual capacity than the approximately 850 mAh typical of the OEM part. These factors can cause earlier-than-expected failure or intermittent RAM retention issues that are difficult to diagnose. Where plant standards permit aftermarket parts, select a reputable industrial supplier, verify connector and chemistry specifications against the OEM data, and test in a non-critical system before fleet-wide deployment.

What happens to my SLC 500 program if the 1747-BA is completely exhausted while the controller is powered down?

If the 1747-BA voltage drops below the CPU's minimum RAM retention threshold during an unpowered period, the SLC 500 loses its stored program and clock data. When main power is restored, the CPU will typically fault or start in a default state with no user program present. Recovery requires reloading the program from an offline backup copy — typically stored on a laptop, programming terminal, or memory module — and reconfiguring any parameters that were not saved. This outcome is avoidable with a maintained battery and a current offline backup; both are standard elements of SLC 500 maintenance practice.

Is the 1747-BA subject to any special shipping restrictions that could affect my order lead time?

Yes. The 1747-BA contains a lithium metal cell with a lithium content of approximately 0.29 g, which places it within the scope of lithium battery transport regulations. Depending on your location and the carrier, this may restrict air freight options and require ground transport or dedicated hazmat packaging, which can extend effective lead time compared to non-restricted components. Cross-border shipments — including between Canada and the United States — may require additional documentation. When ordering, confirm with your distributor whether the shipment will be subject to hazmat fees or ground-only routing, and plan your order timing accordingly relative to your maintenance window.

Why Order Through LeadTime.ca

  • LeadTime.ca ships Allen-Bradley SLC 500 components worldwide, including regions where direct Rockwell distributor coverage is limited or lead times are extended.
  • Our team can confirm 1747-BA compatibility against your specific SLC 500 CPU catalog number before the order is placed — eliminating wrong-part returns.
  • We understand lithium battery shipping regulations and can advise on transport options and hazmat requirements for your destination before your order ships.
  • Volume pricing and stocking agreements are available for facilities maintaining large SLC 500 installed bases — contact us to discuss spare-parts planning.
  • Hard-to-find and legacy automation components are a core specialty; if availability is constrained through standard channels, we have sourcing resources to locate stock.

At-a-Glance Summary

  • Catalog number: Allen-Bradley 1747-BA — official Rockwell Automation SLC Lithium Battery for SLC 500 controllers.
  • Cell type: FDK CR14250SE, cylindrical 1/2 AA format with pre-attached leads and plug-in connector.
  • Nominal voltage: approximately 3.0 VDC; lithium metal, non-rechargeable chemistry.
  • Typical capacity: approximately 850 mAh (distributor-sourced; for life planning reference only).
  • Lithium content: approximately 0.29 g — subject to lithium battery transport regulations and potential hazmat fees.
  • Country of origin: Japan, per Rockwell and distributor product data.
  • Manufacturer warranty: approximately one year, typical Rockwell Automation terms — confirm with distributor.
  • Not compatible with ControlLogix (1756-BA), MicroLogix 1100 (1763-BA), or other non-SLC 500 controller families.
  • Key ordering rule: verify the SLC 500 CPU documentation explicitly lists 1747-BA before ordering — do not order by memory or visual similarity to other Rockwell batteries.
  • Available through LeadTime.ca with worldwide shipping — contact for volume pricing and lithium transport guidance.

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