P91-3kLi vs Vertiv Liebert PSI5-3000SRT120LIN
Both are 3000 VA / 2700 W, 120V lithium rack/tower UPS. The Vertiv PSI5-3000SRT120LIN is a line-interactive unit in a 3U short-depth chassis. The Xtreme Power P91-3kLi is online double-conversion in 2U, lighter, faster to recharge, rated to 50 °C, with a battery rated for up to 15 years and a 6-year warranty.
What the P91-3kLi brings
Zero transfer time and continuously regulated output, against line-interactive AVR on the PSI5.
2U against 3U for the same 3000 VA / 2700 W.
45.2 lbs against 56 lbs.
10 minutes at 2700 W and 21 at half load, against Vertiv’s 9 and 20.
About 1.5 hours to 90%, against 2 to 3 hours.
Runs in hot closets and edge rooms; the PSI5 is rated to 40 °C.
LiFePO₄ rated for up to 15 years, against 8 to 10 years.
Electronics and lithium battery (USA and Canada), against 5 years. Reduced to 2 years at 40–50 °C; 2 years depot repair elsewhere.
Qualifies for U.S. government, education and public-sector procurement as standard.
P91-3kLi vs PSI5-3000SRT120LIN
| Feature | Xtreme P91-3kLi | Vertiv PSI5-3000SRT120LIN |
|---|---|---|
| Topology | Online double-conversion | Line-interactive with AVR |
| Output capacity | 3000 VA / 2700 W | 3000 VA / 2700 W |
| Rack space | 2U | 3U |
| Depth | 23.8″ rack (24.8″ with bezel) | 16.9″ (15.7″ rack depth) |
| Weight | 45.2 lbs | 56 lbs |
| Runtime at full load | 10 min at 2700 W | 9 min at 2700 W |
| Runtime at half load | 21 min at 1350 W | 20 min at 1350 W |
| Recharge | About 1.5 h to 90% | 2–3 h |
| Battery | LiFePO₄ (LFP), hot-swappable | Lithium-ion, hot-swappable |
| Battery life rating | Up to 15 years | 8–10 years |
| Operating temperature | 0–50 °C (derated above 40 °C) | 0–40 °C |
| Outlets | 1 × L5-30R + 6 × 5-15/20R | 1 × L5-30R + 9 × 5-20R |
| Network card | Optional Web/SNMP | Included |
| Efficiency | 94% online / 98% ECO mode | 98.1% (line-interactive) |
| Warranty | 6-year full (electronics and battery) | 5-year |
| TAA compliant | Yes, standard | Confirm per part number |
Where the PSI5 leads: short depth, at 16.9 inches against 23.8, three more outlets, a network card included in the box, and higher efficiency in normal operation, as line-interactive designs typically are. If depth is the deciding constraint at 3 kVA, the Vertiv fits where the P91 will not.
Vertiv and Liebert are trademarks of Vertiv Group Corp., referenced here for factual comparison only. Vertiv figures are from Vertiv’s product page and published distributor data, checked October 2026; verify current specifications before purchase. Vertiv runtimes are Vertiv’s published figures; some resellers list 7.7 minutes at full load and 18 at half load. The P91-3kLi depth is rack-mounting depth.
Compare the P91-3kLi with Eaton, Vertiv and APC →Choosing between them
Choose the P91-3kLi for servers, storage, network cores and generator-backed sites that need online double conversion, for warm rooms up to 50 °C, for the longest battery life and warranty, and for TAA procurement. Choose the PSI5-3000SRT120LIN where a shallow rack is the deciding constraint and line-interactive protection is enough.
Need 3 kVA in 1U? See the J90 1U online lithium UPS. Need a short-depth unit at lower capacity? See the P91-1kLi, 10.6 inches deep at 1 kVA.
P91-3kLi vs PSI5-3000SRT120LIN: frequently asked questions
What is the difference between the P91-3kLi and the Vertiv PSI5-3000SRT120LIN?
Why does online double conversion matter?
How does runtime compare?
Which fits a shallow rack?
How long do the batteries last?
Is the P91-3kLi TAA compliant?
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