Rackmount battery backups are one of those purchases where the difference between a good choice and a regretted one comes down to space, wattage, and whether you can actually get power out of the box. In the UPS critical power category, the Eaton 5P 1550VA and APC Smart UPS 1500VA sit at different points on those priorities: one is a 1U pure sine wave unit with a battery included, the other is a 2U unit with more outlets and higher wattage but no battery. Both are used units, so condition and accessories matter as much as specs.
Quick verdict
If you want a lower-cost rackmount UPS that takes up one rack unit, the Eaton 5P at $174.99 is the more ready-to-use pick. If you need more outlets and can allocate two rack units, the APC Smart UPS at $249.99 gives you higher wattage and a management interface, but check the battery situation before committing.
At a glance
| Product | Listed price | Form factor | Output | Input/Outlets | Battery |
|---|---|---|---|---|---|
| Eaton 5P 1550VA 1100W 1U | $174.99 | 1U | 1550VA / 1100W pure sine wave | C14 inlet | Included |
| APC Smart UPS 1500VA SMX1500RM2U | $249.99 | 2U | 1500VA / 1200W | 8 outlets | Not included |
Where each product wins
- The Eaton wins where rack space matters most: it fits in a single rack unit and supports a wide 200V-240V input range.
- The APC wins where capacity and outlet count matter: it provides higher wattage and more places to plug in protected gear.
- The APC wins for at-a-glance monitoring, with a front-panel LCD and USB interface.
Product notes
Eaton 5P 1550VA 1100W 1U Rackmount UPS Pure Sine Wave 5P1550GR 200V-240V
The Eaton 5P makes the shortlist because it is a 1U rackmount UPS with pure sine wave output and a lead acid battery included in the listing. That means you're not buying a chassis and then hunting for power storage separately; for a compact network stack, this can be the difference between a quick install and a second sourcing project. It also supports nominal input voltages from 200V to 240V, which is useful for environments operating outside the usual 120V range. The main limitation is condition: this is a used unit with light scratching and scuffing on the chassis, and the listing does not include software, a user guide, or accessory cables. It powers on, but the seller could not test it further, so treat it as a functional-core unit rather than a pristine one.
APC Smart UPS 1500VA SMX1500RM2U USB LCD 2U Rackmount Battery Backup
The APC Smart UPS is the capacity-focused alternative: a 2U rackmount battery backup rated for 1500VA and 1200W, with eight outlets and a USB plus LCD interface for monitoring. For a rack carrying multiple switches, routers, or a small server, that extra outlet count gives you more flexibility when assigning protected devices. The catch is the battery. The listing states that batteries are not included, so the unit can't actually provide backup runtime until you add compatible batteries. The used chassis is in black and is positioned for enterprise/data center settings, but you should factor in the time and cost of finding batteries. If you already have the right cells and a 2U space, this is the better expandable foundation.
Final choice by use case
For a tight rack where every U counts and the lower upfront cost matters, the Eaton 5P is the pick. It delivers clean sine wave power in a single rack unit and keeps the upfront cost lower. For a rack with room for 2U and a need to protect more devices, the APC Smart UPS offers a higher wattage ceiling and more outlets. If this is your first rackmount UPS, the Eaton is the safer starting point; if you're expanding an existing battery-backup setup, the APC gives you more headroom to grow.
