Altronix AL176ULB Single Output Power Supply/Charger
The Altronix AL176ULB is a regulated DC power supply and battery charger engineered for access control and networked security systems where uninterrupted power availability is mandatory. This unit converts 24/28VAC input to a stable 12VDC output at 1A maximum capacity, and includes integrated battery backup capability so that door locks, readers, and control relays remain operational during AC mains failure. The AL176ULB incorporates supervised operation with AC fail detection, low battery monitoring, and battery presence verification—critical for life-safety deployments and systems that must maintain egress compliance during power loss. Its compact 5.3" × 3.1" × 1.4" board form factor fits retrofit and new-build installations alike.
Key Features
- Single 12VDC regulated output, 1A maximum: Delivers stable, filtered DC power suitable for door strikes, electromagnetic locks, access control readers, and relay coils. The 1A ceiling means this unit backs up lightweight loads—a typical electromagnetic door lock draws 0.6–0.8A, leaving a safety margin for supervision circuits and pilot lights.
- Integrated battery backup support: Accepts external sealed lead-acid or gel-cell batteries (sized by the integrator) to sustain critical loads during extended AC outages. The charger maintains float voltage automatically, keeping the battery ready without overcharge risk.
- AC fail detection with supervised notification: Integrated relay circuit signals the control panel or monitoring station the instant mains power is lost, enabling alarm annunciation or automatic failover logic. No external supervisor module required.
- Low battery and battery presence supervision: Monitors battery voltage in real time. If the battery drops below threshold (e.g., after prolonged outage), the AL176ULB notifies the system; battery disconnection is also detected and reported, preventing silent loss of backup.
- Fire alarm disconnect functionality: Complies with life-safety codes requiring power disconnection upon fire alarm signal—a non-negotiable feature in facilities with integrated security and fire systems. Prevents access control from interfering with emergency egress during evacuation.
- UL Listed and UL 294 recognized for Access Control Class 2: Meets the rigorous electrical and safety standard for access control power supplies, ensuring insurance and code compliance in commercial and institutional deployments. UL 294 Class 2 designation means the unit is suitable for systems protecting life safety.
- Operating temperature range 0°C to 49°C (32°F to 120°F): Suitable for indoor mechanical rooms, electrical closets, and conditioned spaces. Not rated for outdoor or unheated cabinet mounting—choose a heated or climate-controlled enclosure if ambient may fall below freezing.
- Lifetime Limited Warranty: Altronix backs the AL176ULB for the life of the product, provided it is not subjected to misuse, overvoltage, or physical damage. Replacement or repair decisions rest with the manufacturer.
Integration and Compatibility
The AL176ULB integrates into any access control or security system requiring 12VDC power with battery backup and AC fail supervision. It is commonly deployed in systems using Altronix VertiLine or other access control platforms, as well as third-party readers, magnetic locks, and relay logic. The 24/28VAC input typically comes from a building-code-compliant transformer or, in larger systems, a dedicated UPS output. Battery selection (amp-hour rating) and charger sizing are determined by load analysis—consult the AL176ULB datasheet for float voltage and charging characteristics. The supervision relay outputs are dry contacts suitable for connection to any access control panel or networked monitoring system.
When to Choose a Different Model
If your load exceeds 1A at 12VDC, or if you require multiple independent 12VDC outputs (e.g., separate circuits for locks and readers), consider higher-capacity Altronix multi-output power supplies or larger single-output units in the same family. If your installation demands 24VDC output instead of 12VDC, specify a 24V variant. If AC mains supervision alone is sufficient and battery backup is not required, a simpler regulated supply without charger capability may reduce cost and component count.
Frequently Asked Questions
Q: Can the AL176ULB support an electromagnetic door lock and an access reader simultaneously?
A: Yes, provided the combined steady-state current does not exceed 1A. A typical electromagnetic lock draws 0.6–0.8A and a reader draws 0.2–0.3A, so most common combinations will operate. During lock release or reader activation, brief current spikes may occur; confirm your specific devices do not exceed the 1A maximum before commissioning.
Q: What battery type and capacity should I use with the AL176ULB?
A: The unit supports sealed lead-acid or gel-cell batteries. Size (amp-hour capacity) depends on runtime requirement and load. For example, a 7Ah battery can supply 1A for roughly 7 hours; 12Ah for approximately 12 hours. Consult the AL176ULB datasheet for float voltage specification and charger output current to confirm compatibility with your chosen battery.
Q: Is the AL176ULB suitable for outdoor or unheated enclosures?
A: No. Operating temperature range is 0°C to 49°C (32°F to 120°F). In climates where ambient may fall below freezing, mount the AL176ULB in a heated electrical closet or use a thermostatically controlled cabinet heater to maintain internal temperature.
Q: Does the AL176ULB require a separate AC fail relay module?
A: No. The AL176ULB includes integrated AC fail detection with a built-in relay contact. When mains AC is lost, the relay switches state automatically, allowing the control panel to detect and log the event without an external module.
Q: What is the fire alarm disconnect feature, and when is it required?
A: The fire alarm disconnect removes power from the access control load when a fire alarm is triggered, ensuring that electromagnetic locks and other devices do not prevent emergency egress. This feature is typically required by building code in commercial facilities with integrated security and life-safety systems. Confirm your local code and AHJ (Authority Having Jurisdiction) requirements before installation.
Q: Does the AL176ULB come with a battery, or must I purchase one separately?
A: The unit does not include a battery. You must procure a sealed lead-acid or gel-cell battery separately, sized to your runtime and load requirements, and connect it to the AL176ULB's battery terminals. Refer to the datasheet for voltage and polarity details.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix AL176ULB is a workhorse for access control backup—I see it deployed in dozens of small-to-mid-sized commercial and institutional systems where code compliance and unsupervised AC loss are genuine concerns. The 1A capacity and integrated AC fail relay mean you can mount this module in an electrical closet and have a complete supervised power chain without layering on a separate relay card. The fire alarm disconnect is non-negotiable for any facility with shared security and life-safety infrastructure, and the UL 294 Class 2 rating gives your AHJ confidence that it meets the standard.
Technical Highlights:
- Regulated 12VDC output at 1A: Tight voltage regulation ensures electromagnetic locks and readers remain responsive even under load transients. The 1A hard ceiling is real—overload protection will disconnect the output, so load analysis is mandatory.
- Integrated AC fail relay with low-battery and battery-presence supervision: Three separate supervised states (AC present, battery healthy, battery absent) report back to the control panel via dry relay contacts. No guesswork: the system knows instantly when mains is lost and whether the backup battery is still alive.
- 24/28VAC input with automatic charger float: The charger holds a sealed lead-acid battery at float voltage (approximately 13.6V for 12V batteries) indefinitely, preventing sulfation and overcharge damage. Select your transformer output carefully—undersized transforms cannot supply full 1A continuous under low AC input (24VAC is lower than 28VAC; voltage sag matters).
Deployment Considerations:
- Battery selection is on the integrator: the AL176ULB does not ship with a battery, and runtime depends entirely on amp-hour rating and load. A 7Ah battery gives roughly 7 hours of 1A supply; plan for 12–24 hours of backup if your facility has extended post-outage protocol. Battery cycling (repeated shallow discharge/recharge) extends life significantly compared to full-depth discharge.
- The 0°C to 49°C operating range excludes unheated or outdoor cabinets. In northern climates, temperature drop accelerates battery chemistry and reduces available capacity by 50% or more at freezing. A heated enclosure is not optional in cold regions.
- Fire alarm disconnect is a code requirement in many jurisdictions for integrated systems. If your facility does not have a fire alarm hardwired to access control, you may not need this feature, but leaving it in place adds no cost and future-proofs the installation.
Deploy the AL176ULB in any access control system where AC mains loss for more than a few minutes is unacceptable—medical facilities, secure entry, detention, or data centers with life-safety requirements. The combination of UL 294 compliance, integrated supervision, and charger capability makes it the right choice for code-driven installations where simplicity and reliability outweigh feature count.
