Altronix AL175UL Dual-Output Power Supply and Battery Charger
Overview
The Altronix AL175UL is an enclosure-mount power supply and battery charger built for mid-range access control and building security systems. It delivers selectable 12VDC or 24VDC output at 1.75A continuous maximum current across two independent Class 2 rated channels. The AL175UL handles dual-output architectures common in door lock, reader, and auxiliary device installations — meaning you can provision power to multiple security circuits from a single unit without daisy-chaining supplies. Integrated battery backup and AC fail supervision ensure the system remains operational during mains loss, while fire alarm disconnect functionality meets code requirements for supervised shutdown in emergency scenarios.
Key Features
- Selectable 12VDC or 24VDC Output: Field-configurable voltage lets you match the power requirements of your readers, locks, and control boards without stocking multiple SKUs. Simplifies inventory management in larger deployments with mixed-voltage equipment.
- 1.75A Continuous Maximum per Output: Each of the two channels can deliver 1.75A independently. In practice, this supports mid-tier door lock draw (typical electromagnetic locks run 0.6–1.2A), reader power (0.3–0.5A), and auxiliary relay circuits (0.2–0.5A) on the same output without exceeding spec. Exceeding this spec causes thermal shutdown, so verify cumulative load on each channel before installation.
- Two Independent Class 2 Rated Outputs: Class 2 certification means low-voltage, limited-power safety classification — standard for access control. Dual outputs eliminate the need for external distribution blocks in many installations. Each channel is independently fused and monitored.
- Battery Backup and Charging Capability: Accepts an external 12V or 24V sealed lead-acid or gel-cell battery (not included). During AC loss, the charger disconnects and the battery supplies both outputs. On AC restore, the charger re-engages automatically. This is critical for fail-safe locks and door readers that must remain powered during blackout — a non-negotiable requirement in most jurisdictions.
- AC Fail Supervision Monitoring: A dedicated output signals when AC mains fail, triggering system responses like unlocking fail-safe doors, alerting a security panel, or logging the event. This is mandatory in life-safety installations and meets NFPA 101 requirements.
- Fire Alarm Disconnect Functionality: In the event of a fire alarm signal, the AL175UL can be configured to shut down power to access control circuits (forcing doors to fail-safe state). CSFM and MEA NYC approvals confirm this meets California and New York fire code requirements — a hard requirement in any jurisdiction with fire marshal oversight.
Integration & Compatibility
The AL175UL mounts inside a standard electrical enclosure and accepts 115VAC, 60Hz input at 0.6A (standard 15A circuit breaker protected). Screw terminals handle both AC input and DC output connections — no specialized connectors. It integrates with any access control panel, standalone door controller, or reader that accepts 12VDC or 24VDC Class 2 power. The UL294 (Access Control) certification ensures compatibility with major control manufacturers (HID, Salto, Honeywell, Bosch, etc.) and fire alarm integration boards. CSFM and MEA NYC approvals are non-negotiable if you're deploying in California or New York City buildings subject to fire and building code inspections.
When to Choose a Different Model
If your load exceeds 1.75A per channel (for instance, multiple high-draw electromagnetic locks on a single output), look for a higher-amperage power supply in the Altronix family. If you need more than two outputs, consider a modular or larger enclosure-mount unit. If AC redundancy (dual input feeds or generator backup) is required, consult a systems integrator about pairing the AL175UL with an external UPS or inverter. The AL175UL provides battery backup for short blackouts — not extended outages.
Frequently Asked Questions
Q: Does the AL175UL support external battery backup?
A: Yes. It charges and backs up to an external 12V or 24V sealed lead-acid or gel-cell battery (matched to your selected voltage output). During AC loss, the battery automatically supplies both outputs. Typical backup duration depends on battery capacity and load — a 7Ah battery at 1.75A would provide roughly 4 hours of backup.
Q: Can I use both outputs simultaneously at full 1.75A?
A: Each output is independent and can deliver 1.75A. However, internal thermal design limits total combined draw. Verify your cumulative load on both channels does not exceed safe thermal dissipation — typically 2.5–3A combined before the charger enters thermal throttling. Consult the datasheet for detailed thermal curves, or contact the manufacturer with your specific load profile.
Q: Is the AL175UL compliant with New York City building code?
A: Yes. It carries MEA NYC approval, confirming compliance with New York City Department of Buildings electrical and fire code requirements. CSFM (California State Fire Marshal) approval also covers California jurisdictions.
Q: What happens if the battery is not installed?
A: The AL175UL will operate normally on AC mains, delivering power to both outputs. The battery backup and AC fail supervision features will not function. Battery installation is optional but strongly recommended for any system requiring fail-safe operation during power loss.
Q: Does the AL175UL include a battery?
A: No. The AL175UL is a charger and power supply only. You must source a suitable external 12V or 24V sealed lead-acid or gel-cell battery separately, sized to your backup duration requirements.
Q: What is the fire alarm disconnect feature, and why do I need it?
A: If your building's fire alarm system is integrated with access control, fire code (NFPA 101) may require access control power to shut down upon alarm, forcing all doors to fail-safe (locked or unlocked per code). The AL175UL fire alarm disconnect input allows this supervised shutdown. Your fire alarm panel sends a signal; the AL175UL cuts power to the access control circuit. This is mandatory in life-safety designs.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix AL175UL hits a sweet spot for access control architects working with mid-tier door lock and reader circuits. Most integrators I've worked with underestimate how often a dual-output, battery-backed supply eliminates the need for a larger, more expensive centralized UPS. The selectable 12VDC or 24VDC output and 1.75A per-channel capacity handles electromagnetic locks, readers, and relay circuits in the same enclosure without requiring external distribution logic.
Technical Highlights:
- Dual Independent Class 2 Outputs at 1.75A Each: Most electromagnetic locks draw 0.8–1.2A; readers add 0.3–0.5A. The AL175UL lets you run a lock and reader on the same channel without exceeding 1.75A, or split them across channels. This matters because it eliminates the undersized power supply problem where you pick a 2.5A unit only to have the installer jam three devices onto one channel and hit thermal limits at 18 months.
- AC Fail Supervision Output: A dedicated contact output signals when mains AC fails, instantly informing your access control panel or SIEM. In practice, this triggers automatic fail-safe unlock in a power outage, meeting code and user expectations. No external relay needed.
- Battery Charger Built-In, Not Add-On: Unlike a power supply that requires a separate charger module, the AL175UL integrates charging into the same footprint. You wire a battery once, it charges during AC present, and backs up automatically on AC loss. One fewer point of failure in the cabinet.
- CSFM and MEA NYC Approvals: If you're deploying in California or New York, these certifications are non-negotiable. I've seen projects delayed months because the specified power supply lacked MEA NYC or CSFM clearance. The AL175UL ships ready for both jurisdictions.
Deployment Considerations:
- Thermal Limits Under Full Load Across Both Channels: The unit is spec'd for 1.75A per output, but running both channels at full load simultaneously approaches thermal ceiling. Don't assume you can reliably draw 3.5A total. Verify your cumulative load (lock + reader + relay on both channels) against the datasheet thermal curve. If you're near the edge, go one size up to avoid warranty-voiding thermal shutdown.
- Battery Sizing Is Your Responsibility: The AL175UL charges but does not include a battery. A 7Ah gel-cell at 1.75A load delivers roughly 4 hours backup. If your client expects 8-hour backup (common in healthcare or critical facilities), you're doubling battery cost and cabinet space. Size early and get client sign-off in writing.
- Fire Alarm Integration Requires Pre-Planning: The fire alarm disconnect input is simple (a dry contact), but tying it to your fire panel's alarm relay output requires coordination with the fire alarm contractor before installation. If your access control and fire panels are from different vendors, this is a common integration point for miscommunication. Test it on-site before closing out the project.
Position the AL175UL in single-door or small multi-door access systems where you need battery backup, code compliance (NFPA 101, CSFM, MEA NYC), and enclosure-mount form factor. It's not for large distributed systems with dozens of readers — those need centralized power and UPS infrastructure. But for a 2–4 door card-access installation with fail-safe locks and a requirement to stay powered during a 4-hour blackout, the AL175UL costs less and installs faster than building a mini UPS rack.
