Altronix SMP3PMP4 Supervised 12VDC Power Supply Charger
The Altronix SMP3PMP4 is a regulated 12VDC power supply designed to deliver reliable backup power and integrated battery charging for security system installations. It accepts standard transformer outputs (16–28VAC input range) and converts them to supervised 12VDC with real-time monitoring of power health — AC failure, battery status, and low-battery conditions. This supervision layer is critical: it lets your access control, alarm, or camera system detect power faults before they cascade into false alarms or missed events.
Key Features
- Supervised operation with AC Fail, Low Battery, and Battery Presence monitoring: Instead of blindly assuming power is good, the SMP3PMP4 actively reports faults. Your panel sees AC loss in real time, triggering appropriate alarms or failover routines — not just a dead unit.
- Dual output circuit: 0.5A @ 12VDC and 4A @ 12VDC / 6A @ 12VDC selectable configuration: Separate fused channels let you run critical circuits (a door lock, a sensor) on the low-draw output and less-critical loads on the main output. Prevents a single short from cascading across all equipment.
- Integrated battery backup charging circuit: The SMP3PMP4 includes an onboard charger — you plug in a lead-acid or sealed battery on the backup terminals, and the unit automatically keeps it charged. When AC fails, the battery seamlessly supplies 12VDC to the system. No external charger needed; no management overhead.
- Four-fuse protection architecture: Four separate fuses isolate individual circuits. A short on one load doesn't blow a main fuse and kill everything — just that circuit. Faster troubleshooting, less downtime.
- Input voltage range 16–28VAC: Standard transformer outputs drift. This 12-volt spread accommodates real-world transformer variance without regulation loss, reducing nuisance resets or voltage warnings in cold climates where transformer secondary voltage can sag.
- Compact form factor: 7″L × 4″W × 1″H: Fits into most standard 12V power supply enclosures, DIN rail mounting, or wall-mounted cabinets. Low footprint is critical in retrofit access-control installations where cabinet space is already tight.
Deployment Context
The SMP3PMP4 is purpose-built for security backbone power — not general-purpose 12V supplies. It shines in multi-door access control systems where you need backup, in alarm panels requiring supervision, and in camera systems using local 12V UPS supplies. The battery charging circuit eliminates the need to pair it with a separate charger, reducing BOM cost and wiring complexity. The four-fuse architecture is a deployment win if you're powering a mix of loads (locks, readers, sensors) that would otherwise share a single point of failure.
Because this is a supervised unit, your system firmware will see AC faults — useful for alerting integrators to power issues before they become lockouts or false alarms. If you're integrating the SMP3PMP4 into an access control or alarm power infrastructure, confirm that your panel's input supports the AC Fail and Low Battery relay outputs (normally provided as open-collector dry contacts). If you need networked surveillance power or PoE-based camera distribution, this is not the right product — you'd want a PoE injector or managed PoE switch instead.
Integration & Compatibility
The SMP3PMP4 is a standalone power supply; it does not require software configuration or network access. You wire transformer AC input, 12V load outputs, and optionally a backup battery to the screw terminals. The supervision outputs (AC Fail, Low Battery, Battery Present) are dry-contact relays that connect to your panel's alarm inputs or power monitoring circuit. CE compliance confirms electrical safety and EMC — standard for security equipment in most jurisdictions.
Warranty & Support
Lifetime Limited Warranty covers manufacturing defects. Specific coverage (labor, shipping, battery replacement) should be verified with an authorized Altronix distributor.
Frequently Asked Questions
Q: Can the SMP3PMP4 run continuously, or is it only for backup?
A: The SMP3PMP4 is designed to run continuously, delivering regulated 12VDC as long as AC input is present. The battery is a backup layer — it supplies power if AC fails. There is no time limit on continuous operation.
Q: What size backup battery should I use with the SMP3PMP4?
A: That depends on your runtime requirement and total load. The SMP3PMP4 provides integrated charging for sealed lead-acid or gel-cell batteries; consult the datasheet for maximum charging current and recommended battery capacities. If you need 1 hour of runtime with a 4A load, you'd size a battery accordingly — battery selection is not specified in the SMP3PMP4 technical data.
Q: Does the SMP3PMP4 work with non-battery backup systems?
A: Yes. If you don't need battery backup, you can omit the battery and use the SMP3PMP4 as a regulated 12VDC supply with supervision only. The AC Fail and Low Battery outputs will still report power health to your panel.
Q: Is the SMP3PMP4 suitable for outdoor cabinets?
A: The SMP3PMP4 is a general-purpose power supply. If mounting outdoors, you must place it inside an enclosure (like an outdoor power cabinet) to protect it from rain and UV. The unit itself is not IP-rated for direct weather exposure.
Q: What is the difference between the 4A and 6A output configuration?
A: The SMP3PMP4 offers a selectable configuration: you can jumper or configure it for either 4A or 6A on the main output. This flexibility lets you tailor the unit to your site's peak load at installation time. Check the datasheet for jumper location and thermal derating at the higher current.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix SMP3PMP4 solves a real integration headache: most generic 12VDC supplies lack supervision or integrated battery charging. You're forced to pair a main supply with a separate charger, manage two units in a tight cabinet, and lose visibility into power health until the system goes down. The SMP3PMP4 consolidates this — regulated output, battery charger, and AC/battery fault monitoring all in a 7×4-inch board. That compact footprint matters when you're retrofitting a cabinet that's already hosting a panel, readers, and lock PSUs.
Technical Highlights:
- Four-fuse architecture with dual outputs (0.5A + 4A/6A selectable): Isolates critical circuits. A short on a lock coil doesn't blow the main fuse and kill your readers. In a multi-door site, this is the difference between one malfunctioning door and a complete system reset.
- 16–28VAC input range: Real transformers drift with load and temperature. A 24VAC transformer can sag to 16V in winter or under heavy load. This spread ensures the SMP3PMP4 doesn't fall out of regulation or trigger false low-voltage alarms during peak demand.
- Integrated battery charging with AC Fail relay: No external charger — the circuit auto-manages a lead-acid battery, and when AC drops, the relay output triggers your panel's backup routine. You get supervised transition to battery power, not a blind switchover.
Deployment Considerations:
- The SMP3PMP4 is a power supply, not a UPS with display or management software. You do not monitor it over network — you rely on the relay outputs (AC Fail, Low Battery) wired to your panel's alarm inputs. If your panel doesn't support supervised power inputs, you won't see faults in real time.
- Battery sizing is your responsibility. The unit provides charging current; you must calculate runtime based on your load and battery capacity. An undersized battery will deplete in minutes and you'll have false alarms once backup runs dry.
- The 4A/6A selectable output means you must commission the correct jumper position at installation. If you wire it for 6A but your load is actually 4A, you're not over-stressed. If you wire for 4A and later add a second lock pulling 3A, you're back to the bench reconfiguring jumpers — plan ahead.
The SMP3PMP4 is built for integrators who need to cram reliable backup power into a single compact board without sacrificing supervision or circuit isolation. If you're building a 4–8-door access-control system with mixed loads (locks, readers, motion sensors), this eliminates the tangled wiring and multi-unit footprint of building backup yourself. If you're running a single monitored door lock and don't need UPS runtime, a simpler non-supervised supply is cheaper — but you lose fault visibility.
