SL700U Standby UPS System, 700VA/370W, 8 Outlets, Slim Profile, Black

Just what I needed for the storms. Working great when the power goes out, on,out on during bad weather.

The CyberPower SL700U is the kind of UPS you keep around not because it’s a powerhouse, but because it’s a polite, dependable little buffer that smooths out life’s electrical hiccups. It’s slim, unobtrusive, and perfect for the gear that really just needs clean, uninterrupted power long enough to avoid a reboot—modems, routers, ONTs, or those tiny-but-critical devices that absolutely should not experience a brownout. As a surge protector plus brief-runtime UPS, it does its job without fanfare or fuss, and that’s exactly what you want in a unit this size. In day-to-day use, the SL700U behaves like a compact shock absorber. Voltage drops? It catches them. Blips and flickers? It shrugs and gives you the extra seconds you need. Full outages? Well… it’ll keep your small gear running for 10–15 minutes, maybe a bit more if the load is tiny—but this is a UPS you choose for coverage, not marathon endurance. It’s not something you’d use for a full networking rack or anything mission-critical. But for protecting your modem during ISP maintenance, or keeping your router alive while your bigger UPS is rebooting, updating, or being swapped? It’s perfect. Its real value shows up when paired with larger systems. If you’ve got a bigger UPS or portable power station as your primary backbone, this little CyberPower becomes the perfect “inline buffer”—absorbing those moments where the big device switches modes, resets a circuit, or needs a firmware update. Instead of a hard network drop, everything downstream keeps humming along as if nothing happened. For anyone who works with layered power systems or wants belt-and-suspenders protection for the gear that holds everything together, the SL700U fits that niche beautifully. It’s not designed to be an all-purpose safety net, but within its intended role it’s wonderfully reliable. Treat it as the “hiccup protector” for sensitive electronics, especially in modest or home office setups, and it will earn its spot. Just don’t ask it to run a switch stack or an office during a blackout—this is the helpful sidekick, not the hero. Pros • Slim, compact, and easy to place behind desks or network shelves • Ideal for modems, routers, ONTs, and other low-draw devices • Smoothly handles flickers and short drops without reboots • Perfect as a buffer behind larger UPS or power systems • UL certified and generally very reliable for its class Cons • Very limited runtime—10–15 minutes max under typical loads • Not suitable for full racks or high-draw equipment • Standby design means it’s not as smooth as line-interactive models • Battery longevity is decent, but not exceptional

I asked the Amazon community a while ago about if anyone knew how big the internal circuit board was for the Cyberpower SL700U battery backup? No one could give me an answer and since this unit seemed to be the smallest, most compact design for a larger 700 watt backup supply on the market, I decided it would do for my purposes. I am writing this review not as an end use of the actual device, but to re-purpose the battery backup’s structure, it still functions as intended, just in a different package and I believe that customers may like to see how these units work as well as how they can be modified (yes, you will void the warranty) I make computer hard drive backups and restorations every 2 months, for myself and others I help with their operating systems, so I use an external data backup device: Startech SM2DUPE11. Previously I used an earlier model that could not do NVMe style drives but was still efficient and quick. When backing up data of any type, it is best to have a power supply that won’t fail on you else you may lose your destination drive or corrupt the source data if you have a blackout. The UPS is the answer. The duplicator needs a home, so a good solid case to carry and store it in makes sense. Last, the UPS, which I integrated into the case, adding in a couple of features and using components to replace the circuit board mounted power switch and power LED indicator light. I decided to add in a power receptacle in case I needed to plug something in while doing the backup off site. Designing the layout on an acrylic plastic board and then drilling, cutting and filing out slots and holes, modifying the two heat sinks on the Cyberpower SL700U’s circuit board and adding in a separate 12 volt DC power supply to power two small 40 mm fans to cool those two heat sinks I shortened, all of this needed careful planning on how to arrange everything. The Startech duplicator’s power supply adapter also needed a parking stall in the layout. So after removing it from it’s case, and trying a few positions with two slimmer 6 volt batteries to power the UPS during a power outage, I had my plan. The original Cyberpower battery was 2 inches thick, and obviously I could not use this effectively if trying to place it flat inside of the carry case I used, the Nanuk 910 case. I found a flatter, 1.3” thick, 6 volt battery to use, but I would need two of them instead of one. You can replace a 12 volt battery with two 6 volt ones if you connect them in series. This gave me the advantage of increasing the amp hour rating from the Cyberpower’s 5 amp hour 12 volt battery to 7 amp hours for the replacements. My project took a while to accumulate all the needed components, all ordered through Amazon, and once I had replaced the short battery cables on the circuit board with lengthened ones, and soldered on wires to connect the switch and LED light, I was ready to assemble. The photos show the SL700U disassembled then it’s circuit board being put together and mounted to the underside of the acrylic plastic board. I consulted with the Startech technical support to confirm that their duplicator being placed so close to the UPS power supply would not cause any issues in its operation and they confirmed that there should be no problem. The project is done and my SL700U powers my duplicator station, protecting this investment from power failures as well as surges during normal operation. I am pleased that I chose this particular device, the Cyberpower SL700U, as it was a great compact design that I could incorporate into my plan and provide power for the nominal 60 watt power usage of the duplicator. This should prove me with many years of service. Hope this helps you decide if the SL700U is for you.

I bought the CyberPower SL700U UPS after the fifth time my computer shut off mid-email like it was rage-quitting reality. At this point, the power in my area is more of a “vibe” than a utility, so I figured I needed something that wasn’t going to flinch every time the lights flickered like we’re in a low-budget horror movie. Enter: CyberPower SL700U – the quiet hero I didn’t know I needed. It sits there like a chunky plastic loaf of bread, humming gently, judging my cable management, and waiting to leap into action the next time my electricity decides to take an unscheduled coffee break. It has 8 outlets – 4 for battery backup, and 4 that just protect your devices from rogue lightning bolts or your neighbor's sketchy DIY wiring. Of course, I plugged in everything valuable, including my modem, router, PC, and the lamp that makes me feel productive. There’s even USB ports so I can charge my phone while I emotionally process another blackout. First power outage? This thing kicked in like a bodyguard at a nightclub. Everything stayed on. My screen didn’t flicker. My soul didn’t leave my body. I felt like I had achieved adulthood. It gave me a whole 10 minutes to gracefully save my work and Google whether I need to stock up on canned beans. My only complaint? The alarm. When the power goes out, it beeps like it’s personally offended. Not a gentle reminder, no—this thing screams like a fire drill at a haunted daycare. But hey, at least I know it’s working. Bottom line: if you like your electronics alive, your data intact, and your heart rate slightly elevated during power events, the SL700U has your back.

Nice device, seems to work well. Like that it has USB ports but they should be battery protected as well... they are just straight power.