The 1500VA UPS class is the most widely deployed UPS size in North America because it delivers the highest usable power on a standard 120V, 15A dedicated circuit—without requiring a 20A outlet or special wiring. This makes it the ideal UPS class for IT racks, network closets, retail POS systems, medical carts, AV/broadcast installations, and edge computing environments.
Xtreme Power offers the industry’s most complete lineup of 1500VA UPS systems, available in both cost-effective VRLA models and long-life Lithium Iron Phosphate (LFP) models with up to 15-year battery life.
J90-1.5kLi
Why 1500VA Matters
- Maximum power from a standard 15A receptacle—no electrical upgrades required
- Ideal watt output (900W–1450W) to support servers, firewalls, switches, and storage systems
- Available in tower, rack/tower, and ultra-dense 1U rack configurations
- Extended runtime options available on select models
- Lithium Iron Phosphate battery models offer maintenance-free operation and lowest total cost of ownership
Why Watt Rating Matters More Than VA
The VA (volt-ampere) rating reflects the apparent power of a UPS, but the watt rating represents the actual usable power available to your equipment. For maximum system compatibility and performance, watt capacity is the most important factor.
| UPS Class | Typical Power Factor | Usable Power (Watts) | Efficiency Insight |
| Entry-Level UPS | 0.60 PF | 900W | Supports only basic office and non-critical loads |
| Professional / Online UPS | 0.90–0.97 PF | 1350–1450W | Delivers near-maximum usable power from a 15A circuit—ideal for IT and edge environments |
Xtreme Power’s professional 1500VA UPS models deliver the highest usable watt capacity available on a standard 15A circuit—ideal for IT and edge infrastructure.
Xtreme Power 1500VA UPS Lineup – Side-by-Side Comparison
| Model | Usable Power (Watts / PF) | Topology | Battery Type | Form Factor | Positioning | Ideal Applications |
| S71-1500 | 900W (0.6 PF) | Line Interactive | VRLA | Tower | Lowest-cost protection | Small office, POS, non-critical loads |
| P80-1500 | 1350W (0.9 PF) | Line Interactive | VRLA | 2U Rack/Tower | Cost-effective; extended runtime available | IT racks, branch networks, retail environments |
| T91-1500 | 1450W (~0.97 PF) | Online Double-Conversion | VRLA | Tower | Industrial-grade online protection; extended runtime capable | Sensitive electronics, medical carts, industrial and mission-critical systems |
| P91-1500 | 1450W (~0.97 PF) | Online Double-Conversion | VRLA | 2U Rack/Tower | Online protection; extended runtime capable | Edge computing, network closets, IT infrastructure |
| P91-1.5kLi | 1450W (~0.97 PF) | Online Double-Conversion | Lithium Iron Phosphate (LFP) | 2U Rack/Tower | Up to 15-year battery life; 6-year warranty | Enterprise, government, healthcare, long-life applications |
| J90-1500 | 1350W (0.9 PF) | Online Double-Conversion | Lithium Iron Phosphate (LFP) | 1U Rack | Up to 15-year lithium; individually controllable outlets; 6-year warranty | Edge computing, broadcast/AV, high-density IT environments |
Runtime Performance – 1500VA UPS Models
Runtime is critical in determining how long connected equipment can remain operational during a power loss. The chart below provides real measured runtimes across load levels.
Runtime Table (Minutes)
| Model | Capacity (W) | 300W | 600W | 900W | 1200W | 1350W | 1450W |
| S71-1500 | 900 | 11 | 3 | 1.5 | – | – | – |
| P80-1500 | 1350 | 47 | 18 | 11 | 7 | 6 | – |
| P91-1.5kLi | 1350 | 47 | 22 | 14 | 10 | 8 | – |
| J90-1500 | 1350 | 32 | 16 | 11 | 8 | 7 | – |
| T91-1500 & P91-1500 | 1450 | 35 | 14 | 8 | 5 | 4 | 3 |
Extended Runtime Capability
The following models support external battery packs for long-duration applications: P80-1500, T91-1500 and P91-1500
Why Lithium Iron Phosphate (LFP) Is the Future of UPS Technology
Lithium Iron Phosphate offers the most advanced energy storage for UPS systems, delivering superior performance and longevity compared to VRLA batteries.
Key Benefits:
- Up to 15-year design life
- 3,000–5,000 charge/discharge cycles
- Operates up to 50 °C (122 °F)
- Maintenance-free, no battery replacements required
- Environmentally safe and thermally stable
Xtreme Power 1500VA Lithium Models:
Which 1500VA UPS Is Right for You?
| Requirement | Recommended Models | Key Benefit |
| Lowest initial cost | S71-1500 | Essential protection |
| Rackmount value | P80-1500 | Extended runtime capability |
| Mission-critical tower | T91-1500 | True online isolation |
| Mission-critical rack | P91-1500 | Scalable online power protection |
| Longest battery life | P91-1.5kLi | Up to 15-year lithium battery |
| Maximum rack density | J90-1500 | 1U lithium with outlet control |
Frequently Asked Questions
Q. What does 1500VA mean on a UPS?
A. 1500VA is a measure of the apparent power capacity of the UPS. However, the real usable power is determined by the watt rating (W), which reflects the actual power your equipment can use. Xtreme Power 1500VA UPS models provide between 1350W and 1450W, delivering the maximum usable power available from a standard 120V, 15A circuit.
Q. How many watts can a 1500VA UPS support?
A. It depends on the power factor of the UPS. Entry-level models support around 900W, while Xtreme Power professional and online models support 1350–1450W. The higher the watt rating, the more equipment you can protect without risking overloads.
Q. Do I need a special outlet for a 1500VA UPS?
A. No. All Xtreme Power 1500VA UPS models are designed to operate on a standard 120V, 15A dedicated circuit. You do not need any special wiring or a 20A receptacle.
Q. How long will a 1500VA UPS run?
A. Runtime varies by load and battery type. At a 600W load:
- Basic VRLA models (S71) provide 3 minutes
- Professional VRLA models (P80, T91, P91) typically provide 14–18 minutes
- Lithium models (P91-1.5kLi, J90) provide 16–22 minutes
Extended runtime models (P80, T91, P91) can be configured with additional battery packs to run for hours, depending on load.
Q. What is the difference between VRLA and Lithium Iron Phosphate (LFP) UPS batteries?
A. See below
- VRLA batteries provide low initial cost but require replacement every 3–5 years.
- Lithium Iron Phosphate batteries offer up to 15-year life, withstand higher temperatures, support more discharge cycles, and require no maintenance or replacement—resulting in a lower total cost of ownership.
Q. Which 1500VA UPS is best for long-term reliability?
A. The P91-1.5kLi and J90-1500 are the best long-term investments. They feature Lithium Iron Phosphate batteries rated for up to 15 years with 3,000–5,000 cycles, eliminating the need for battery replacements.
Q. Do 1500VA UPS systems support extended battery packs?
A. Yes. The following models support extended runtime battery packs: P80-1500, T91-1500, P91-1500. These models can scale runtime significantly for applications requiring longer backup durations.
Q. What makes Lithium Iron Phosphate (LFP) safer than other lithium chemistries?
A. LFP is inherently stable, non-flammable, and does not experience thermal runaway. It is the safest lithium battery technology available for UPS applications and is approved for healthcare, government, and mission-critical environments.
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