Altronix SMP5E 1-Output 4A Power Supply with Battery Backup
The Altronix SMP5E is a single-output regulated power supply and battery charger designed to provide backup power and charging capability for access control systems, door strike equipment, alarm panels, and auxiliary security devices. The unit accepts 24 or 28VAC input and delivers a selectable output voltage of 6, 12, or 24VDC at up to 4A continuous—enough to power multiple door locks, readers, or control modules without requiring a separate charger circuit. The built-in battery backup function maintains power to connected equipment during AC supply interruptions, a critical requirement in any facility where access control cannot tolerate gaps.
Key Features
- Field-Selectable Output Voltage (6/12/24VDC): Match the SMP5E output to your equipment's rated voltage without swapping units. This flexibility reduces spare-parts inventory and simplifies logistics across multi-site deployments.
- 4A Maximum Output Current: Supports simultaneous operation of multiple loads—typically 2–3 door strikes, a reader, and an access controller—without thermal throttling or reset.
- 24/28VAC Input: Accepts standard transformer secondary voltage from existing facility wiring or a dedicated low-voltage transformer.
- Integrated Battery Charging: The SMP5E charges connected batteries automatically when AC is present and switches seamlessly to battery power on AC failure. No external charger or UPS required.
- Single Isolated Output: Provides a clean, isolated DC rail—critical for minimizing noise on access control data lines and preventing ground-loop interference in mixed analog/digital installations.
- Lifetime Limited Warranty: Altronix backs the unit for the life of the original purchaser, reducing replacement risk over typical 5–10 year system lifecycles.
Why Choose This Model
Access control and door security systems require uninterrupted power to function. Unlike passive power supplies, the SMP5E combines regulated DC output with active battery charging, ensuring that door locks and readers stay powered during brief AC outages. The field-selectable voltage output eliminates the need to stock multiple SKUs—install one part number across 6V, 12V, and 24V circuits by changing a jumper or DIP switch.
The 4A output rating is sufficient for most single-door or small multi-door installations. If your load approaches or exceeds 4A continuous, or if you need to power both access control and auxiliary circuits (such as IP cameras or outdoor lighting), you may need to evaluate a higher-capacity unit or a multi-output access control power supply from the Altronix line.
Integration & Compatibility
The SMP5E integrates into any access control system that accepts 6, 12, or 24VDC input and does not require regulated AC output. It pairs with standard door strikes, magnetic locks, access readers, and alarm control panels. Battery capacity depends on your choice of external sealed lead-acid battery; the SMP5E provides the charging logic and regulator. Consult your battery manufacturer's specifications and the access control planning guide to calculate runtime based on load amperage and battery amp-hour rating.
When to Choose a Different Model
If you need multiple isolated outputs for different voltage zones, consider a multi-output variant in the Altronix access control power family. If your total load exceeds 4A, a higher-amperage supply will prevent voltage sag under peak load. If you require an integrated enclosure with DIN-rail mounting, review the full Altronix power supply catalog for enclosed or modular options.
Frequently Asked Questions
Q: Does the SMP5E require a separate battery?
A: Yes. The SMP5E provides the power supply and charging circuit. You must connect an external sealed lead-acid battery (typically 7–17Ah) to enable backup operation. The unit charges the battery automatically when AC is present.
Q: What is the backup runtime with a standard battery?
A: Runtime depends on battery capacity and load. A 7Ah battery at 4A delivers roughly 1.75 hours of backup; a 17Ah battery provides approximately 4 hours. Consult the battery datasheet and your load profile to confirm.
Q: Can I adjust the voltage output in the field?
A: Yes. The SMP5E is field-selectable via jumper or DIP switch (exact method depends on the revision). No tools other than a small screwdriver or jumper removal tool are needed. Verify the current revision before installation.
Q: Is the SMP5E suitable for outdoor or harsh environments?
A: The SMP5E is designed for indoor, climate-controlled installations. If you require outdoor mounting, you must house it in an outdoor-rated enclosure and ensure all terminals and connectors are protected from weather and corrosion.
Q: What is the warranty coverage?
A: The SMP5E carries a Lifetime Limited Warranty, covering defects in materials and workmanship for the original end-user. Damage from misuse, environmental exposure, or incorrect input voltage is typically not covered. Review the full warranty terms with the seller or Altronix directly.
Q: Does the SMP5E work with both 24VAC and 28VAC transformers?
A: Yes. The SMP5E input is rated for 24/28VAC, accommodating both standard 24VAC commercial transformers and some legacy 28VAC secondary supplies. Verify your transformer output before connection.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix SMP5E solves a real problem: most access control circuits require uninterrupted power, but many facility transformers fail or lose AC without warning. Unlike a passive power supply, the SMP5E includes integrated battery charging—you connect an external sealed lead-acid battery, and the unit handles the rest. The field-selectable 6/12/24VDC output is a practical touch that reduces part count across mixed-voltage deployments.
Technical Highlights:
- 4A Continuous Output: Sufficient for 2–3 door strikes, a reader, and an access panel without thermal throttling. Peak loads above 5A or sustained draws near 4A will degrade battery charge time, so size your battery and load conservatively.
- Single Isolated Output: Isolation is critical in access control—shared grounds between power and data lines introduce noise that can corrupt reader communication. The isolated output prevents this coupling.
- 24/28VAC Input: Accepts both common 24VAC transformers and legacy 28VAC supplies, but verify your source voltage before installation. Overvoltage on the input will damage the unit.
- Lifetime Warranty: Unusual in the power supply category and reflects Altronix's confidence in the design. In practice, failures are rare if input voltage stays within spec and the unit is not exposed to moisture.
Deployment Considerations:
- Battery selection is critical—undersized batteries provide insufficient runtime; oversized batteries waste money and space. Calculate load in amps and desired backup duration (typically 2–4 hours) before ordering the battery.
- The SMP5E does not monitor battery health or provide low-voltage alerts. You must implement external monitoring (such as a relay output on your access panel) to detect battery failure or deep discharge.
- The unit is designed for indoor, controlled environments. Outdoor or damp installations require a protective enclosure and regular inspection of terminals for corrosion.
Deploy the SMP5E in single-door or small multi-door access control systems where battery backup is non-negotiable and you need a compact, field-configurable power supply. For large multi-zone facilities, consider a higher-amperage or multi-output variant to reduce the number of supplies on your rack.
