If you’ve read anything hereabouts you likely know that I make significant use of Ubiquiti’s Unifi network gear. I started with their Wi-Fi Access points many years ago, eventually adopting a few of their managed switches, the UXG Max router and most recently the Unifi 5G Backup. It’s safe to say, I’m committed to the Unifi product line.
Further, living in hurricane alley, with a power utility that could rightfully claim to be the lords of darkness, I believe in planning for powerline issues. For longer outages we have a portable generator. For short term issues, we have a couple of good UPS deployed. The best is Mr. Eaton, an Eaton Powerware 9130 that I acquired in 2021.
Mr. Eaton is getting to the point where it may be time to refresh his batteries. The one I have needs three batteries. A complete set would cost around $130. That said, using lead acid batteries is old school. More modern UPSs use lithium ion or lithium phosphate batteries.
Impressive Software Features
The software based features are seriously interesting. I certainly appreciate the ability to toggle the state of each outlet on the UPS. Also, the ability to monitor how much power each is drawing. The fact that it’s all within the Unifi ecosystem is very appealing.
There’s a built in network interface, with the ability to automatically shutdown a UNAS or UNVR server when power is lost. Compatibility with NUT means it can be integrated with non-Unifi devices, too.
Looking into the published specifications:
Battery Choice
The UPS 2U Pro has lead acid batteries. These are the type of batteries that have been common in everything from automobiles to UPS for decades. They are cheap. They work, but they need to be replaced every few years.
Newer UPSs may use Lithium Ion or Lithium Iron Phosphate batteries. These have higher energy density resulting longer runtimes for the same mass. Lithium Phosphate batteries are also much longer lived. I’ve seen manufacturers quoting 10 years before replacement is required.
At this price point, I would have hoped for a more advanced battery formulation. Even if that means using a smaller, cheaper battery. In a UPS that’s part of larger backup power strategy, the issue isn’t generally runtime. Especially when the UPS can trigger the load devices to perform a graceful shutdown.
Pure Sine Wave Output
The claim is “pure sine wave output.” That means the circuitry in the UPS that creates AC power from DC is capable of creating clean sine waves. This may also be referred to as “low distortion” or “low THD” power. When we hear that “some devices are sensitive to dirty power” that’s generally about this.
We know from earlier study of traditional generators vs inverters that utility power must legally stay under 5% THD. A traditional synchronous generator may be as much as 20% THD. Inverter power is typically well below 2%.
On this basis, pure sine wave capability is good. Much better that crude approximation using square waves.
Design Topology
Ubiquiti is very clear that the implementation is a “Line Interactive” design. That means the UPS sits across the power line, in parallel with the load. When the utility power wobbles or stops, it acts to sustain power to the load. While it may provide some filtering, it does not fully buffer the load from the utility power.
Sidebar: Fuji Electric has nice, short comparison of different UPS designs.
In the great Texas Freeze of 2021 we learned that our two inexpensive, line interactive, UPSs (Belkin & APC at the time) would not run from a portable generator. This is what motivated the move to a dual-conversion UPS for our network core.
Since 2021 we moved to a Predator 9500 inverter as our source of backup power. So, conceptually we could get by with line interactive UPSs. However, I’ve noted that the 1RU Cyberpower UPS in the house is much more sensitive to power line issues than the stoic and utterly reliable Mr. Eaton.
I bought the Eaton 9130 as new-old-stock. The model had been discontinued, so inventory was liquidated. Where it would have cost around $1k new, I paid just $200 without batteries. A set of replacement batteries cost me another $150.
Summary
The Unifi UPS 2U Pro is certainly appealing. The software features are very attractive. I’d love to give one a try. It’s priced at around $730. That’s not bad. However, for that price, I would have hoped for the use of a superior battery chemistry. If it cost just a bit more, say around $1k, I’d expect a dual conversion design.