Quick Take
Backup power for a rack starts with a simple question: does the listing include everything you need, or is it a component waiting for batteries? This set of four UPS critical power listings spans an APC external battery pack, a new 3000VA Smart-UPS XL, a used 2700W Smart-UPS with a network card, and a Vertiv 1500VA rack/tower unit. The listed prices run from $149.97 to $279.98, but the real difference is what arrives in the box. One listing is a runtime extension pack, another is a UPS without batteries, and the other two are complete systems-one new, one used. The real decision is less about the total price and more about whether you are buying a complete system or a component.
Listed Price Comparison
| Product | Listed Price | Price Bar |
|---|---|---|
| APC SMX120RMBP2U Smart UPS External Battery Pack Rackmount | USD 149.97 | |
| APC Smart-UPS XL SUM3000RMXL2U 3000VA 120V Rackmount Tower UPS New | USD 271.99 | |
| APC SMX3000RMLU2UNC 110V 2700W Smart-UPS RackMount w/ Network Card - See Desc | USD 279.98 | |
| Libert Vertiv PSI5-1500RT120 1500VA/1350W Rackmount UPS Battery Backup Qty 1 | USD 149.99 |
Decision Matrix
| Product | Use Case | Limitation |
|---|---|---|
| APC SMX120RMBP2U | Extending runtime on a compatible Smart-UPS X system | External pack only; batteries and faceplate not included |
| APC Smart-UPS XL SUM3000RMXL2U | New 3000VA unit for rack or tower use | Capacity may exceed small-closet needs |
| APC SMX3000RMLU2UNC | High-wattage unit with network card | Batteries and rackmount brackets not included |
| Libert Vertiv PSI5-1500RT120 | Complete 1500VA rack/tower UPS | Used; capacity lower than the 3000VA APC units |
Product Notes
APC SMX120RMBP2U Smart UPS External Battery Pack Rackmount
This is not a standalone UPS; it is designed as an external battery pack to extend runtime for compatible Smart-UPS X systems. The 2U rackmount form factor fits standard rack environments, and the APC mpn identifies the intended family. The main limitation is the packing list: batteries, faceplate, and network management card are not included, and the unit is used. If you already own the compatible Smart-UPS X chassis and need extra runtime, this is the targeted add-on. If you are starting from scratch, it will not deliver backup power on its own.
APC Smart-UPS XL SUM3000RMXL2U 3000VA 120V Rackmount Tower UPS New
The only new unit in this set, the Smart-UPS XL SUM3000RMXL2U combines 3000VA capacity with 120V input and a form factor that works in either a rack or a tower. If you want a sealed-box UPS with plenty of headroom for servers, network switches, and other equipment, this is the one to compare against the used options. The 2850W maximum power gives you a clear picture of the load it can support. The trade-off is simple: you are paying more for a new 3000VA unit than for the used 1500VA Vertiv or the used external pack. For a small rack that rarely draws more than 1500VA, the extra capacity may be more than you need. The new condition and rack/tower flexibility are the main reasons to choose it.
APC SMX3000RMLU2UNC 110V 2700W Smart-UPS RackMount w/ Network Card - See Desc
This used APC Smart-UPS is positioned at the top of the price spread, and for good reason: the title points to 2700W and an included network card, with a serial port, USB port, and seven outlets listed in the description. That makes it a strong candidate if your rack needs high wattage and remote management. The model designation APC SMX3000 ties it to the Smart-UPS X family. The important catch is the "See Desc" in the title: batteries and rackmount brackets are not included, so you would need to source those separately. The description also says the outer case may show minor scratches or scuffs from normal use. This listing is for the UPS base, not a drop-in complete backup system.
Libert Vertiv PSI5-1500RT120 1500VA/1350W Rackmount UPS Battery Backup Qty 1
This Libert Vertiv PSI5-1500RT120 is a complete UPS battery backup, not a battery pack or a chassis awaiting parts. It offers 1500VA/1350W with pure sine wave output, automatic voltage regulation, and an LCD status display-details that matter for sensitive gear. The listing states it was pulled from a working environment and tested, which is useful context for a used unit. The capacity is lower than the 3000VA APC options, so it fits a rack with modest power needs better than a high-density server row. It comes in a rackmount/tower form factor and includes Qty 1 as stated in the title. For a straightforward used UPS, this is the complete option in the group.
Final Recommendation by Use Case
- If you already own a compatible Smart-UPS X system and want extra runtime, the APC SMX120RMBP2U is the add-on to target.
- If you want a new unit with room to grow a 120V rack, the APC Smart-UPS XL SUM3000RMXL2U is the sealed-box pick.
- If you need high wattage and a network card and you are comfortable adding batteries, the APC SMX3000RMLU2UNC is the used high-capacity option.
- If you want a complete used UPS with 1500VA of capacity, the Libert Vertiv PSI5-1500RT120 is the direct choice.
