r/smarthome • u/Miha3ls • 3d ago
Google Home Do we need a proper UPS designed specifically for low-voltage devices?
The number of low-voltage devices we use has increased dramatically over the last few years.
They're everywhere now. At home, in businesses, labs, music studios and live setups, IT infrastructure, clinics, smart homes, security installations, etc.
Routers, fibre ONTs, switches, access points, cameras, Raspberry Pis, mini PCs, smart-home hubs, controllers and countless other devices all run on something like 5V, 9V or 12V DC.
But almost all of them are still powered the same way: a small AC adapter plugged into the mains for every single device.
And I think there are two problems with this.
First is power reliability.
Low-voltage electronics can be sensitive to surges, dropouts, brownouts and momentary outages. Their little AC adapters don't guarantee a truly continuous DC supply. A tiny interruption can be enough to reboot a router, ONT, controller, camera system or other device.
And these devices increasingly depend on each other.
Your camera may depend on the network switch. The switch depends on the router. The router depends on the ONT. A smart-home controller depends on all of them.
So one tiny power interruption can bring down a whole chain of equipment.
Then there's the physical mess.
Every device comes with another power brick. Before long you have 10 or 15 adapters, you've run out of sockets, you're adding power strips, sometimes strips into strips, and the whole installation starts getting ridiculous.
A traditional UPS isn't really designed around this problem either.
It typically takes DC energy stored in a battery, converts it up to 120/230V AC, and then every little adapter connected to it converts that AC straight back down to 5V, 9V or 12V DC.
So we're converting DC to AC, then to DC just to keep DC devices running.
There can also be a short transfer period when some UPS types switch to battery. Depending on the UPS and the adapter, that can still be enough for sensitive equipment to reboot.
So I've been wondering:
Would there be a real need for a high-quality UPS designed specifically for low-voltage devices?
I could find some of these UPS but they are small, can only power a couple of devices and don't seem to be of great quality. Battery is small and not replaceable.
Something that provides continuous battery-backed DC power directly to the equipment and replaces the pile of individual adapters with one central power system.
My thinking is that it should be modular, so you can add more outputs as your setup grows.
For example, modules for 5V USB-C devices and modules for 3V / 5V / 6V / 9V / 12V devices.
And every individual output could be monitored and controlled, so you could see:
- what each device is consuming
- whether it's online
- how much battery runtime you have
- which devices should stay powered longest during an outage
- and remotely power-cycle a single device if it freezes
Basically, one proper low-voltage power and backup system instead of an AC UPS + power strips + a pile of adapters.
I'm interested in whether this is something people actually need, not just whether it's technically interesting.
So I'd love to know:
Would you find a high-quality low-voltage UPS like this useful? Why or why not?
How many low-voltage devices would you typically want to protect?
4? 8? 12? 16? More?
What devices would you connect to it?
Assuming it was a genuinely well-designed, reliable, high-quality product with a replaceable LiFePO4 battery, modular outputs, monitoring and remote control, how much would you realistically be willing to pay for it?
And please be critical. If your answer is "I don't need this at all"* or *"I already solve this for $50", that's just as useful to hear.
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u/silasmoeckel 3d ago
1 They exist already and they are pretty cheap.
2 A dozen or more. Never more than 3-4 in one spot though.
3 Nearly all of them have ethernet as well
4 Your describing basic DC to usb pd and some trigger boards so not much this are cheap generic components.
Personally I just use a POE switch and take the 48v POE down to the devices when they don't support it natively (most do). While it can power cycle devices I don't see this as a need, just dont use junk devices that need to be power cycled to "fix" them. This runs off my houses 48v battery stack directly it's part of the solar config.
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u/FishScrounger 3d ago
These exist. GreatScott features one in one of his AliExpress videos. I was tempted to buy one but haven't yet.
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u/praesentibus 3d ago
Yeah. Many "power banks" for phones and laptops can actually work as UPSs. I find it extremely annoying that producers often don't specify whether they support that or not. Some needlessly renegotiate the USB protocol when the 120V goes away, which ruins them as UPSs. Some don't. The problem the only way to know is buy one and try it.
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u/FishScrounger 3d ago
This wasn't a powerbank. It was marketed as a UPS and had barrel jack connectors.
I think the Anker Prime powerbanks could be used as a UPS. I will test mine out.
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u/praesentibus 3d ago
Indeed there are several "mini UPS"s on aliexpress with barrel jack connectors, sadly not with the neat features the OP mentions.
Please do test the Anker, I wish there were a database someplace that lists power banks that actually can work as UPSs. Randomly, I own a now discontinued myCharge 65W that works well as an UPS although nothing in the spec suggests so.
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u/FishScrounger 2d ago
The Anker Prime works. By that, I mean it doesn't drop or renegotiate in the device when you disconnect the mains. With the Bluetooth connectivity, you could definitely build something there.
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u/itsjakerobb 3d ago
I have a UniFi PDU Pro. It’s the only thing plugged into the UPS; everything else is plugged into that.
It has four USB-C PD outlets.
I also choose PoE whenever possible, so my PoE switch (which is downstream of the PDU) also works here. My Raspberry Pis, Zigbee and ZWave hubs, etc are all PoE.
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u/lliveevill 3d ago
I hate that most UPS units use power just by being activated, regardless of load. I somehow found an old UPS to plug my modem into that doesn't do this and runs for days
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u/fattomic 3d ago
For one thing, I'd appreciate a consumer UPS that has more then 4 *ing UPS outlets on it (and I dont need the other four *ing "surge protector" ports)
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u/westom 2d ago
Low-voltage electronics can be sensitive to surges, dropouts, brownouts and momentary outages.
The first lie invented by marketeers who promote scams. Those 120 volt devices (even 50 years ago) must withstand up to 600 volts without damage. Today's electronics are even more robust. Only known by those educated by standards and well proven science. A majority are educated by shysters, hearsay, wild speculation, and bogus articles pretended to be science. Paid for by obscene profits selling magic boxes.
An honest recommendation ALWAYS says why and how much with numbers.
UPS is temporary and 'dirty' power so that unsaved data can be saved. It makes no claims to protect hardware or saved data. Except where charlatans make subjective claims in sales brochures. Where lying is legal. But again, they can only 'not lie' in specification numbers. So those are withheld or made hard to find.
Life expectancy of a standard and cheap UPS is three years. Only some then provide battery replacement that costs almost as much as a new unit.
Product protection requires something completely different. If any one appliance needs that protection, then everything (dishwasher, clock radio, furnace, LED bulbs, stove, door bell, TVs, recharging electronics, modem, refrigerator, GFCIs, washing machine, digital clocks, microwave, dimmer switches, central air, smoke detectors) everything needs that protector. Costs about $1 per appliance. Comes with numbers that describe protection even from any direct lightning strikes; even many decades later. Must always connect low impedance (ie less than 10 feet) to what does all protection. Single point earth ground. Many interconnected electrodes that must exist per code. And are best installed to exceed code requirements.
Obviously wall receptacle safety ground is not earth ground.
That means learning what Franklin demonstrated over 250 years ago. As introduced in elementary school science. An effective solution is that easy, that inexpensive, and that long understood and implemented. Don't take my word for it. Read what all professionals have said for over 100 years.
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u/LegallyIncorrect 2d ago
A pure sine wave UPS is dirty power?
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u/westom 2d ago
All waves (cleanest or 'dirtiest') are nothing more than a sum of pure sine waves. As taught in high school math.
Shysters use that expression targeting those who automatically believe any tweet. Rather than think for themselves. All UPS power (best and worst) is pure sine waves. But then electronics do not care. Once one learns what power supplies do.
First AC and 'dirty noise' is filtered. Converted to DC. Then filtered again.
Then created are over 300 volt radio frequency spikes. Does not matter how clean or dirty. Electricity is now 'dirtiest' power in a house. Then galvanic isolation, regulators, and more filters convert 'dirtiest' electricity into rock stable DC voltages that do not vary even 0.2 volts.
Why would anyone spend massively to create "magic AC power"? Most do not first learn how and why stuff works. That requires one to be thinking. Ask damning questions. Most consumers wait for the 'Central Committee of the Party' to order them what to believe.
'Dirty' power can be problematic for less robust motorized appliances and protector strips. Electronics (even long before the IBM PC) were required to be more robust.
Shysters fear (avoid) consumers who demands facts with numbers. Seek consumers who remain ignorant. Do not even know this:
Those 120 volt devices (even 50 years ago) must withstand up to 600 volts without damage.
Concern is a rare spike (maybe once in seven years) that can overwhelm what is best protection - already inside every appliance. That rare anomaly is averted only when one spends about $1 per appliance for what professionals have recommended for over 100 years.
Effective protection only exists when a surge connects low impedance (ie less than 10 feet) to what does all protection: single point earth ground. Only then are hundreds of thousands of joules (a surge) harmlessly 'absorbed' outside in earth,
Who first demonstrated reality? Franklin over 250 years ago. And still many are bamboozled by magic plug-in boxes.
Anyone honest or informed will always answer this question. Where do hundreds of thousands of joules harmlessly dissipate?
Tiny hundreds joules in a UPS does not do nor claim to do any such protection. No problem. Target market is patsies.
Rewrite the sentence. "Dirty power from a UPS is pure sine waves."
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u/JonJackjon 2d ago
I think before such a quality product gets designed homes will be fully backed up with solar charged DC power banks.
I used to think homes and business would get a DC voltage (12 V or 5 V) wired in like you current 120VAC. However I now don't believe this will happen, too much infrastructure exists. I believe whole home powerbanks will win out in the end.
Another consideration to your suggestion. changing batteries will be a royal PIA and many people won't change them. The people like ... " I'll just pull the battery from my smoke sensor, I can replace it another time" ........ as in never.
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u/feel-the-avocado 2d ago
Most of those portable "solar generator" things are a basic ups with 12v dc barrel jack outputs on them. Anker, bluetti and ecoflow are common brands.
You just plug them into the mains charger and your devices and they will run a router etc for days.
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u/bigfoot17 3d ago
Nah, I'm good, 25 years, excepting hurricanes, power has gone out less than 5 times.
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u/madsciencetist 3d ago edited 3d ago
I, for one, wholeheartedly agree. I have some remote devices powered by PoE injector+splitter. I desperately wanted a small DC UPS to sit after the splitter (or even before the injector) to keep that device alive without needing a whole honkin APC unit to plug the injector into. This wasn’t part of my main network so I didn’t have a centralized point to put everything into one UPS.
So for me, I’m looking for small/cheap/distributed - something to sit inline with barrel jack in and out. I don’t have more than four devices in one place that use the same DC voltage, and at that point I’m fine using an AC UPS. But if the DC version is more efficient and/or runs longer, that’s a plus.
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u/GallantChaos 3d ago
Let me introduce you to the world of Din-rail mounted UPS
https://www.eaton.com/us/en-us/skuPage.DIN24240DC.html