Altronix MAXFIT35E Dual-Output Expandable Power Supply System
The Altronix MAXFIT35E is a wall-mount expandable power system built for security installations that need simultaneous 12VDC and 24VDC outputs with battery backup in a single enclosure. Two independent single-output power supply/chargers deliver 12VDC or 24VDC at 6A and 12VDC at 10A concurrently — meaning you can run 24VDC devices like certain access control hardware alongside 12VDC cameras or locks without splitting the job across two separate panels. The enclosure accommodates up to four 12VDC/12AH sealed lead-acid or gel batteries, giving you meaningful standby time without sourcing a second cabinet. Altronix carries a lifetime warranty on this product, which is a meaningful commitment for infrastructure that lives inside walls and above ceilings for years.
Overview
Purpose-built for commercial security power supplies and access control infrastructure, the MAXFIT35E addresses a common field problem: a single installation often needs two voltage rails. Running separate power supplies for each rail wastes cabinet space, adds wiring complexity, and multiplies failure points. The MAXFIT35E consolidates both into a 16.5" x 20.5" x 6.25" wall-mount enclosure with supervised outputs and LED status indicators, giving installers visibility into AC health, DC output status, and battery condition without pulling a panel door. For more on Altronix power distribution and how to size backup capacity, explore the Altronix product line.
Key Features
- Dual simultaneous voltage outputs (12VDC and 24VDC): Two independent power supply/chargers run in parallel — Option A provides 12VDC or 24VDC at 6A, Option B provides 12VDC at 10A. This lets a single enclosure power a mixed-voltage installation: 24VDC electric strikes or mag-locks alongside 12VDC cameras and motion detectors, without a second supply.
- Up to four internal batteries (12VDC/12AH each): The enclosure natively houses four sealed lead-acid or gel batteries — no external battery cabinet required for standard standby configurations. For longer hold times (40AH or 65AH), a separate enclosure is needed, but the four-battery internal configuration covers the majority of commercial deployments without additional hardware.
- Instantaneous failover on AC loss: Upon mains failure, the MAXFIT35E switches to battery instantly — no relay delay, no momentary dropout. For access control points, this means door hardware never loses power long enough to default to an unintended state during a utility glitch.
- Supervised AC and battery status via Form C contacts: Both AC failure and battery condition are monitored via Form C dry contacts, which can be wired directly into an alarm panel or access control system for centralized fault reporting. You'll know about a dead battery or a lost AC feed before it becomes a field emergency.
- Three LED status indicators: Dedicated LEDs for 115VAC presence, DC output status, and battery condition (discharged or disconnected) give a technician immediate visual confirmation during commissioning or a service call — no multimeter required for a first-pass health check.
- Over-voltage protection and filtered/regulated outputs: Filtered and regulated DC outputs protect sensitive electronics from noise and transients. Over-voltage protection adds a hard ceiling that prevents a component failure from damaging downstream devices — relevant when load includes access control boards or camera processors.
- 5A/250V input fusing: Input-side fusing at 5A/250V provides branch circuit protection without requiring a separate fused disconnect, simplifying rough-in and reducing the number of components an inspector needs to review.
- Operating range 0°C to 49°C (32°F to 120°F): Rated for the thermal envelope typical of equipment rooms, utility closets, and conditioned mechanical spaces. Not designed for unconditioned outdoor environments — verify ambient temperature if the enclosure will be in an attic or loading dock closet that experiences summer extremes above 49°C.
- Compact wall-mount footprint: At 16.5" wide by 20.5" tall by 6.25" deep and 21.2 lbs, the MAXFIT35E is manageable for a single installer to mount on a stud wall. The shipping weight of 26.6 lbs reflects packaging — plan for a two-person lift when mounting at height or in tight mechanical rooms.
Integration & Compatibility
The MAXFIT35E is designed for integration with standard access control systems and commercial security infrastructure. Its Form C supervision contacts are hardware-agnostic and wire into virtually any alarm panel or access control host that accepts dry contact inputs. Battery selection is constrained to sealed lead-acid or gel type — AGM cells in the 12VDC/12AH form factor are the common field choice and are widely available through security distributors. Batteries are sold separately; confirm your battery supplier carries the correct footprint before scheduling the installation. For installations requiring extended backup beyond 12AH per cell, up to 40AH or 65AH configurations are supported but require a separate enclosure — plan accordingly in your BoM. Pair this supply with your NVR or access control head-end for a complete backed-up installation.
Input is 115VAC 60Hz at 6.1A, which draws under one amp of headroom on a 15A branch circuit even with full load — compatible with standard commercial branch circuits. Heat dissipation runs 98 BTU/hr at 12VDC only and 130 BTU/hr when both 12VDC and 24VDC outputs are active; factor this into mechanical room or closet heat load calculations on dense multi-supply installations. For power planning guidance, see our power planning and UPS sizing guide.
Frequently Asked Questions
Q: Can the MAXFIT35E output 12VDC and 24VDC at the same time?
A: Yes. The MAXFIT35E contains two independent power supply/chargers. One provides 12VDC or 24VDC at 6A (Option A), and the other provides 12VDC at 10A (Option B). Both can operate simultaneously, allowing you to run mixed-voltage loads from a single enclosure.
Q: How many batteries does the MAXFIT35E support, and what type?
A: The enclosure accommodates up to four sealed lead-acid or gel batteries rated at 12VDC/12AH each. Batteries are sold separately. For extended backup capacity (40AH or 65AH), a separate battery enclosure is required.
Q: What happens when AC power is lost?
A: Failover to battery is instantaneous upon AC loss — there is no relay delay or dropout. Supervision contacts (Form C) notify your alarm panel or access control system of the AC failure condition.
Q: What is the warranty on the MAXFIT35E?
A: Altronix provides a lifetime warranty on the MAXFIT35E.
Q: Is the MAXFIT35E suitable for outdoor or unconditioned space installation?
A: The MAXFIT35E is specified as a wall-mount enclosure for indoor use, with an operating temperature range of 0°C to 49°C (32°F to 120°F). It is not rated for outdoor installation. Verify that any closet or utility space stays within this range year-round before mounting.
Q: Can I wire the supervision contacts into my existing alarm panel?
A: Yes. Both the AC failure and battery supervision outputs are Form C dry contacts, which are hardware-agnostic and compatible with virtually any commercial alarm panel or access control system that accepts dry contact inputs for fault monitoring.
The detail I keep coming back to on the MAXFIT35E is the instantaneous failover — not "fast" or "near-instant", but genuinely instantaneous upon AC loss. In access control installations where mag-locks or electric strikes are on the load, any detectable dropout can cause a fail-secure door to momentarily release or a fail-safe door to lock out a stairwell. That's a life-safety issue, not just an annoyance, and the MAXFIT35E handles it correctly at the hardware level.
Technical Highlights:
- Dual independent outputs (12VDC and 24VDC simultaneous): Running Option A at 6A alongside Option B at 10A means a single enclosure can power a 24VDC door strike bank and a separate 12VDC camera or sensor circuit without cross-load risk — a real time saver versus managing two separate supplies and their individual supervision wiring.
- Four-battery internal capacity (up to 48AH aggregate): Four 12AH cells in the enclosure gives you meaningful hold time on a realistic mixed load. At 6A continuous draw, four 12AH batteries in a properly designed circuit can sustain output for several hours — enough to cover most commercial power interruptions without a generator transfer.
- Form C supervision on both AC and battery: Both failure modes report out via dry contacts. Wire these into a Bosch, DSC, or Honeywell panel and the monitoring station knows about a missing battery or lost feed before the backup is exhausted — that's the difference between a proactive service call and an after-hours emergency dispatch.
Deployment Considerations:
- The 130 BTU/hr heat load when running both outputs simultaneously is modest on its own, but closets with four or five of these supplies stacked up can accumulate meaningful heat — check the room's HVAC capacity before commissioning a dense multi-supply deployment.
- Batteries are sold separately and are not included in the box. Factor lead time and footprint for four 12AH cells into your installation schedule — confirm your battery supplier has the correct form factor in stock before the job day.
The MAXFIT35E is the right supply for mid-size commercial access control deployments — specifically buildings with mixed-voltage door hardware (24VDC strikes plus 12VDC readers or cameras) where running two separate supplies would double the wall footprint and supervision wiring. Hospitals, corporate campuses, and multi-tenant office buildings with centralized IDF closets are the sweet spot.
