Middle Atlantic S1500R vs Middle Atlantic OL1500R: Specification Comparison
Both the UPS-S1500R and UPS-OL1500R are Middle Atlantic rack-mount UPS units rated at 1500VA, sized at 2RU, and aimed at AV/security integrators powering rack-based equipment. The S1500R belongs to the Select Series while the OL1500R is the Premium Online Series. The key architectural difference is UPS topology: the OL1500R specifies Online Double Conversion, while the S1500R's topology is not stated in its provided specs. This comparison evaluates topology and power quality, physical and installation differences, and protection/compliance attributes.
In This Guide
- What UPS topology does each unit use, and how does that affect power quality delivered to connected equipment?
- How do the two units differ in physical footprint, weight, and rack installation requirements?
- How do the units compare on outlet protection, plug/receptacle type, operating environment, and compliance certifications?
- Which should you choose: the S1500R or the OL1500R?
- Side-by-Side Specs
- FAQ
What UPS topology does each unit use, and how does that affect power quality delivered to connected equipment?
The OL1500R explicitly specifies an Online Double Conversion topology. In this architecture, connected loads run continuously off the inverter, which is fed by a rectifier drawing from AC mains; the battery floats on the DC bus. The result is zero transfer time on mains failure and continuous filtering of input voltage fluctuations, frequency drift, and waveform distortion — the output is always inverter-generated, clean 120 VAC at 15 A (1350 W rated real power).
The S1500R's topology is not stated in the provided specifications. It is listed under a 'Select Series' designation, and its surge protection is described only as 'Basic.' Without a stated topology, buyers cannot confirm whether it offers standby, line-interactive, or double-conversion operation. The absence of a watts rating, output voltage spec, and amperage spec in the S1500R data further limits power-quality comparison. Integrators powering sensitive IP cameras, NVRs, or access control servers where clean, uninterrupted sine-wave output is critical should note this gap.
How do the two units differ in physical footprint, weight, and rack installation requirements?
Both units occupy 2RU and share identical height (3.46 in / 8.8 cm) and width (19 in / 48.3 cm), and both ship with a 10 ft (3.1 m) cord. Depth differs: the S1500R measures 16.5 in (41.9 cm) while the OL1500R is slightly shallower at 15.57 in (39.6 cm), a 0.93 in difference relevant in shallow enclosures.
Weight is notable: the S1500R carries a shipping weight of 54 lbs (24.5 kg), while the OL1500R ships at 53 lbs (24 kg) with a stated product weight of 47.7 lbs (21.6 kg). The S1500R does not provide a separate product weight. Mounting depth range also differs: the S1500R supports 19–32 in (48.3–81.3 cm) rack depth, while the OL1500R supports a wider 20.7–36.2 in (52.6–92 cm) range. The OL1500R also provides 4 mounting points versus 2 on the S1500R, which may affect stability in mobile or high-vibration rack environments. Mount type is explicitly stated as Rack for the S1500R; the OL1500R's mount type is not listed in the provided specs.
How do the units compare on outlet protection, plug/receptacle type, operating environment, and compliance certifications?
Both units provide 8 outlets. The OL1500R specifies NEMA 5-15P plug and NEMA 5-15R receptacles, confirming standard North American 120 VAC compatibility. The S1500R does not specify plug or receptacle type in the provided data. The S1500R lists surge protection as 'Basic' with UL Listed certification. The OL1500R lists RoHS compliance but does not state a surge protection classification in the provided specs.
Operating temperature is specified only for the OL1500R: 32°–104°F (0°–40°C). The S1500R provides no operating temperature range in the provided specs, which is a meaningful gap for installations in non-climate-controlled enclosures or outdoor-rated cabinets. Neither unit is TAA Compliant per the provided specs. The S1500R carries a UL Listing; the OL1500R carries RoHS — these are not equivalent certifications, and neither spec sheet lists both for the same unit, so direct certification parity cannot be confirmed from the data provided.
Which should you choose: the S1500R or the OL1500R?
Our take: The OL1500R is the stronger choice when power quality and zero transfer time are non-negotiable — as is typical for IP security systems with sensitive NVRs, access control panels, or PoE switches. Its Online Double Conversion topology continuously regenerates clean 120 VAC output at a stated 1350 W / 15 A, eliminating transfer gaps entirely; the S1500R's topology is not specified in the provided data, preventing an equivalent guarantee. The OL1500R also supports a wider rack-depth range (20.7–36.2 in vs. 19–32 in) and provides 4 mounting points versus 2, offering more installation flexibility in deep or mobile enclosures. The S1500R carries a UL Listing and is 0.93 in deeper; its real power output and operating temperature limits are absent from the provided specs. Installers requiring a documented topology and rated watt output for load calculations should specify the OL1500R. If budget is the primary constraint and the application tolerates a non-double-conversion topology, the S1500R warrants a datasheet review before selection.
Side-by-Side Comparison
Spec-for-spec, from manufacturer data.
| Specification | Middle Atlantic S1500R | Middle Atlantic OL1500R |
|---|---|---|
| Series | Select Series | Premium Online Series |
| SKU | UPS-S1500R | UPS-OL1500R |
| VA Rating | 1500 VA | 1500 VA |
| Rated Watts | — | 1350 W |
| Topology | — | Online Double Conversion |
| AC Output Voltage | — | 120 VAC |
| Amps | — | 15 A |
| Outlet Count | 8 | 8 |
| Plug Type | — | NEMA 5-15P |
| Receptacle Type | — | NEMA 5-15R |
| Rack Units | 2 RU | 2 RU |
| Height | 3.46 in (8.8 cm) | 3.46 in (8.8 cm) |
| Width | 19 in (48.3 cm) | 19 in (48.3 cm) |
| Depth | 16.5 in (41.9 cm) | 15.57 in (39.6 cm) |
| Mounting Depth Range | 19–32 in (48.3–81.3 cm) | 20.7–36.2 in (52.6–92 cm) |
| Mounting Points | 2 | 4 |
| Cord Length | 10 ft (3.1 m) | 10 ft (3.1 m) |
| Shipping Weight | 54 lbs (24.5 kg) | 53 lbs (24 kg) |
| Product Weight | — | 47.7 lbs (21.6 kg) |
| Surge Protection | Basic | — |
| Operating Temp | — | 32°–104°F (0°–40°C) |
| TAA Compliant | No | No |
| Certification | UL Listed | RoHS |
| Mount Type | Rack | — |
Frequently Asked Questions
Which should you choose: the S1500R or the OL1500R?
The OL1500R is the stronger choice when power quality and zero transfer time are non-negotiable — as is typical for IP security systems with sensitive NVRs, access control panels, or PoE switches. Its Online Double Conversion topology continuously regenerates clean 120 VAC output at a stated 1350 W / 15 A, eliminating transfer gaps entirely; the S1500R's topology is not specified in the provided data, preventing an equivalent guarantee. The OL1500R also supports a wider rack-depth range (20.7–36.2 in vs. 19–32 in) and provides 4 mounting points versus 2, offering more installation flexibility in deep or mobile enclosures. The S1500R carries a UL Listing and is 0.93 in deeper; its real power output and operating temperature limits are absent from the provided specs. Installers requiring a documented topology and rated watt output for load calculations should specify the OL1500R. If budget is the primary constraint and the application tolerates a non-double-conversion topology, the S1500R warrants a datasheet review before selection.
Which unit is better for powering sensitive IP cameras and NVRs that cannot tolerate any power interruption?
Based on the provided specifications, the OL1500R is the appropriate choice. It states an Online Double Conversion topology, which means connected equipment runs off the inverter at all times with zero transfer time during a mains failure. The S1500R does not specify its topology in the provided specs, so that level of protection cannot be confirmed for that model.
Does either unit fit in a shallow rack or wall-mount enclosure?
The OL1500R has a minimum mounting depth of 20.7 in (52.6 cm) and a unit depth of 15.57 in (39.6 cm). The S1500R has a minimum mounting depth of 19 in (48.3 cm) and a unit depth of 16.5 in (41.9 cm). The S1500R's lower minimum mounting depth gives it a marginal advantage in shallower enclosures, though the OL1500R is the shallower unit itself by 0.93 in.
Are either of these units TAA compliant for government or federal security projects?
No. Both the UPS-S1500R and UPS-OL1500R are listed as TAA Compliant: No in the provided specifications. Neither unit should be specified for projects requiring TAA-compliant equipment without further verification from the manufacturer.
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