Altronix MAXFIT37E Dual-Output Expandable Power Supply System
Overview
The Altronix MAXFIT37E is a dual-output, battery-backed power supply system built for commercial security installations where you need simultaneous 24VDC and 12VDC (or 24VDC) distribution in a single wall-mount enclosure. It ships two independent single-output power supply/chargers — one delivering up to 24VDC @ 10A, the other selectable for 12VDC or 24VDC @ 6A — making it a practical fit for mixed-voltage sites running a combination of IP cameras, door controllers, and legacy analog devices side by side. Altronix backs the MAXFIT37E with a lifetime warranty, which is notable in a product class where competitors often cap coverage at one to three years.
Key Features
- Dual Simultaneous Outputs: Option A delivers 24VDC @ 10A; Option B delivers 12VDC or 24VDC @ 6A — both active at the same time, so you can feed high-current 24V door hardware and lower-draw 12V devices from a single enclosure rather than racking separate supplies.
- Filtered and Regulated Output with Over-Voltage Protection: Regulated DC prevents false alarms and resets on sensitive access panels and camera modules — unregulated spikes are a leading cause of nuisance device reboots in the field.
- Instantaneous Failover on AC Loss: When utility power drops, switchover is immediate with no output gap — critical for door controllers where even a brief power interruption can release a fail-secure lock or trigger an alarm event.
- Battery Capacity — Up to Four 12AH/12VDC SLA Batteries Internal: The BC750 enclosure accommodates up to four sealed lead-acid or gel-type 12VDC/12AH batteries internally, giving you up to 48AH of standby capacity on-site. Need more? The supply supports 40AH or 65AH configurations via a separate external enclosure (sold separately).
- Form C Supervision Contacts for AC Fail and Battery: Hardwired Form C dry contacts report both AC failure and battery fault states directly to your panel or monitoring head-end — no polling required, no software dependency.
- LED Status Indicators: Three discrete LEDs confirm 115VAC input present, DC output active, and battery discharged or disconnected — gives a field tech a status read without opening the panel or connecting a laptop.
- Operating Range 0°C to 49°C (32°F to 120°F): Covers typical mechanical room and IDF closet conditions; the 85% relative humidity ceiling means this is an indoor-rated unit — don't deploy it in unconditioned exterior enclosures without additional protection.
- Heat Dissipation: Approximately 197 BTU/Hr. in 24VDC-only mode, 160 BTU/Hr. in dual-output mode — factor this into your closet thermal load calculation before installing in a sealed telecom cabinet.
Integration and Compatibility
The MAXFIT37E accepts 115VAC 60Hz input at up to 7.9A, protected by a 5A/250V fuse. It is sized for North American commercial installations. The BC750 enclosure measures 16.5"W x 20.5"H x 6.25"D and is designed for indoor wall-mount use. Batteries are sold separately — specify sealed lead-acid or gel-type 12VDC/12AH units. For higher standby capacity requirements beyond the four internal slots, a separate battery enclosure is required and available through Altronix's power systems line. This supply fits naturally into projects where an access control panel, IP intercom, or mixed analog/IP camera deployment needs reliable, supervised DC power with documented battery backup — the kind of installation a power supply planning guide would flag as needing Form C fault reporting back to a central monitoring station. If your project also requires PoE delivery for cameras, pair this with a dedicated PoE switch rather than relying on this supply to directly power network devices.
Frequently Asked Questions
Q: Can the MAXFIT37E supply 12VDC and 24VDC at the same time?
A: Yes. The two independent outputs operate simultaneously: one fixed at 24VDC @ 10A, the other selectable at 12VDC or 24VDC @ 6A. You cannot run both at 12VDC at the same time — only the second output is voltage-selectable.
Q: How many batteries does the MAXFIT37E enclosure hold?
A: The BC750 enclosure accommodates up to four 12VDC/12AH sealed lead-acid or gel-type batteries internally, for up to 48AH of standby capacity. Higher capacity (40AH or 65AH) requires a separate external enclosure.
Q: What is the warranty on the MAXFIT37E?
A: Altronix provides a lifetime warranty on the MAXFIT37E per manufacturer documentation.
Q: Are batteries included with the MAXFIT37E?
A: No. Batteries are sold separately. Specify sealed lead-acid or gel-type 12VDC/12AH batteries compatible with Altronix BC750-series enclosures.
Q: How does the MAXFIT37E signal AC power failure or battery trouble?
A: Both AC failure and battery conditions are reported via hardwired Form C dry-contact outputs, which connect directly to a security panel or monitoring head-end without requiring software integration.
Q: Is the MAXFIT37E suitable for outdoor enclosures?
A: No. The BC750 enclosure is rated for indoor wall-mount use only. Operating temperature range is 0°C to 49°C with a maximum 85% relative humidity — unconditioned outdoor or unheated exterior locations are outside the specified range.
The MAXFIT37E is the unit I spec when a project needs two voltage rails and supervised battery backup in one wall-mount footprint. The 24VDC @ 10A output alone handles most mid-size access control panels comfortably, while the selectable 12/24VDC @ 6A second rail gives you the flexibility to feed legacy analog devices or a secondary camera cluster without running a separate supply. The Form C contacts are the detail that matters most for monitored installations — you get a direct hardwired fault signal to the panel rather than relying on network polling.
Technical Highlights:
- Dual Independent Outputs: 24VDC @ 10A and 12/24VDC @ 6A run simultaneously from a single 115VAC input draw of 7.9A — useful when your single-phase circuit budget is tight.
- Internal Battery Headroom: Four 12AH/12VDC SLA slots inside the BC750 enclosure give up to 48AH standby without external hardware; if UL 2050 or client SLA requires longer hold times, the same supply supports 40AH/65AH via a separate enclosure.
- Thermal Load: At 197 BTU/Hr. in 24VDC-only mode, this unit adds meaningful heat to a sealed IDF closet — run your closet thermal calculation before finalizing placement, especially if other active equipment shares the same space.
Deployment Considerations:
- Batteries are sold separately — build the battery line item into your BOM from the start; missing it is one of the most common field delays on power supply deployments.
- Indoor-only rating (0°C to 49°C, 85% RH max) means you need a conditioned or climate-controlled enclosure if the installation space experiences temperature swings or moisture — an unconditioned mechanical room in a cold climate will push this unit outside its operating window in winter.
This supply is well-suited to mid-size commercial access control deployments — a 4–8 door controller installation in a retail, healthcare, or light industrial facility where mixed-voltage device loads, supervised battery backup, and a single compact enclosure footprint all matter on the same job.
