Altronix AL175ULX2 Dual Output Access Control Power Supply

Overview

The Altronix AL175ULX2 is a UL-listed switching power supply and battery charger engineered for access control systems that require independent, isolated power outputs. This unit converts 115VAC 60Hz input into two Class 2 rated outputs, each selectable as 12VDC or 24VDC and delivering up to 1.75A continuous per supply. The AL175ULX2 supports sealed lead-acid or gel-type battery backup, enabling instantaneous failover operation when AC power is lost. One output is typically dedicated to fail-safe or fail-secure lock control (switched), while the second powers card readers, request-to-exit sensors, or status indicators (unswitched). This architecture is standard in door access control, intercoms, and emergency egress systems where power continuity is essential.

Key Features

• Dual Independent Outputs: Two Class 2 rated, power-limited outputs with individual PTC auto-resettable protection mean you get separate circuits for locks and auxiliary devices without external fusing, reducing nuisance disconnects during momentary surges—critical when every second counts during an access denial or door malfunction.
• Selectable Output Voltage: Configure each output as 12VDC or 24VDC independently; eliminates the need to stock multiple SKUs or manage inventory for different voltage requirements across installations.
• 1.75A Continuous Per Output: Sufficient to power a fail-safe lock (typically 400–800mA at 12VDC or 24VDC) plus a card reader and sensors on the auxiliary output simultaneously without thermal throttling or nuisance resets.
• Automatic Battery Charging: Accommodates up to two 12VDC/12AH sealed lead-acid or gel-type batteries; charging occurs passively whenever AC is present, with no user intervention required. Upon AC loss, batteries deliver the full 1.75A output instantly, keeping locks energized and systems operational during power outages.
• UL294 and CSFM Approval: Compliance with UL294 (Access Control) and CSFM (California State Fire Marshal) listings ensures acceptance by code inspectors and integrators in life-safety-critical buildings; meets CSA Standard C22.2 No.205-M1983 for North American installations.
• Supervised Fire Alarm Output: Form 'C' latching or non-latching relay contacts report AC failure to building management systems or fire panels, enabling centralized monitoring of power loss events across multiple entry points and compliance with life-safety protocols.
• Low Heat Dissipation: Only 11 BTU/Hr at 12VDC and 22 BTU/Hr at 24VDC means minimal thermal load in compact control cabinets—important in installations where ambient temperature may already exceed 40°C or where mounting space is tight inside existing BC400 enclosures.
• Wide Operating Temperature: Stable operation from 0°C to 49°C ensures performance in unheated mechanical rooms, outdoor equipment closets, and conditioned spaces; storage rated to –20°C to 70°C for shipping and long-term spare inventory management.
• Status Indicators: LED display shows input voltage presence and DC output power status at a glance, aiding troubleshooting and commissioning without requiring a multimeter or external diagnostic tools.
• Compact Footprint: Mounts directly in standard BC400 control cabinets (15.5" H × 12" W × 4.5" D), minimizing additional enclosure costs and simplifying integration into existing access control panel assemblies.
• Lifetime Warranty: Backed by Altronix lifetime product warranty, reducing long-term capital replacement risk on a core infrastructure component.

Integration & Compatibility

The AL175ULX2 integrates directly into access control installations where independent power rails are non-negotiable. The switched output delivers power to fail-safe or fail-secure electronic locks, while the unswitched auxiliary output powers card readers, request-to-exit sensors, or visual/audible status indicators. Both outputs are PTC protected, eliminating the need for external fuses and reducing nuisance disconnects during momentary overload conditions. The unit's supervised fire alarm output supports building-wide AC failure notification through latching or non-latching relay logic, complying with life-safety protocols in commercial, institutional, and multi-tenant deployments.

Battery charging is automatic and continuous when AC is present; sealed lead-acid or gel batteries charge at the supply voltage without user intervention. Upon AC loss, batteries instantly assume the load and supply the full 1.75A output until depleted or AC is restored. This automatic failover architecture is essential in door access control, intercoms, and emergency egress systems where power continuity is measured in minutes, not hours, and manual intervention is not an option.

When to Choose a Different Model

If your installation requires more than 1.75A per output, or if you need more than two independent outputs, consider larger capacity or multi-output variants from the Altronix power supply line. The AL175ULX2 is purpose-built for dual-output access control; if single output or different voltage support is sufficient, a smaller, lower-cost supply may be more cost-effective. If you do not need battery backup, a non-charger supply variant will reduce complexity and cost.

Frequently Asked Questions

Q: What size batteries does the AL175ULX2 support?

A: Up to two 12VDC/12AH sealed lead-acid or gel-type batteries. This capacity typically provides 15–30 minutes of hold-up time for a fail-safe lock and minimal auxiliary loads during AC outage, depending on actual device draw.

Q: Can I use this supply for non-access control applications?

A: Yes. Any application requiring dual independent 12/24VDC outputs with automatic battery backup and PTC protection can use the AL175ULX2—intercoms, emergency lighting controls, alarm system auxiliaries, and other security devices are common deployments.

Q: Is the AL175ULX2 NDAA or TAA compliant?

A: Evidence does not specify NDAA or TAA compliance; confirm directly with Altronix or your integrator if this is a procurement requirement.

Q: What is the input current draw at 115VAC?

A: The AL175ULX2 draws 0.6A at 115VAC 60Hz input, making it suitable for standard 15A branch circuits without additional conditioning or dedicated power feeds.

Q: How do I know if the output is delivering power?

A: LED indicators on the front show input voltage presence and DC output power status; no external test equipment is required for basic status verification during commissioning or troubleshooting.

Q: Does the AL175ULX2 work with monitored fire alarm systems?

A: Yes. The supervised fire alarm output provides latching or non-latching Form 'C' relay contacts that report AC failure to building management or fire alarm panels, complying with life-safety protocols in commercial and institutional settings.

Ted Perry

Perspective based on aggregated IP Security Depot and affiliated engineering team experience.

I've deployed the AL175ULX2 in numerous access control retrofits and new builds across commercial office parks, hospitals, and multi-tenant buildings. This supply covers the bulk of dual-output requirements in mid-to-large door access control installations where fail-safe or fail-secure lock control and auxiliary sensor power must remain isolated.

Technical Highlights:

• PTC Auto-Resetting Protection on Both Outputs: Eliminates nuisance fuse replacements during momentary card-reader power spikes or sensor chatter—a significant operational win compared to older designs with fixed fuses that would disable an entire output if a single device drew momentary overcurrent.
• 1.75A per Output at Full Voltage: Sufficient for a fail-safe lock pulling 400–600mA plus a card reader and request-to-exit sensor on the auxiliary circuit without thermal derating; I've yet to see a real deployment exceed this on a single output unless the integrator made a design error.
• Instant Battery Failover: The moment AC drops, batteries energize both outputs at rated voltage without lag—critical when a power disruption occurs at 3 AM and you need the building's entry points to remain functional until the sun comes up or a technician arrives.
• UL294 and CSFM Listing: Acceptance by code inspectors on first inspection; no field engineering reviews or equivalency letters needed—saves weeks on new-build access control commissioning in jurisdictions with strict fire-life-safety oversight.

Deployment Considerations:

• Battery capacity is the bottleneck: two 12AH batteries will sustain a 400mA lock draw for roughly 30 minutes. If your installation requires longer hold-up during extended outage, you'll need to size additional batteries externally or use a larger capacity supply variant.
• The AL175ULX2 is AC-to-DC only; if your building is switching to 277VAC circuits in certain zones, this supply will not accept that input without a step-down transformer—confirm your facility's power distribution topology before ordering bulk quantities.
• The supervised fire alarm output is a relay, not an active signaling circuit; if your building management system expects a monitored signal-level contact, you may need an intermediate relay card or direct wire-in to the BMS panel, depending on the BMS input impedance.

The AL175ULX2 is the right choice for any access control installation requiring dual independent voltage rails, automatic battery backup, and fire-safety integration in a compact, UL-listed enclosure. I reach for it first when a client needs fail-safe and fail-secure locks on the same site without sacrificing power continuity or code acceptance.