Coming from UPS Recomendations - #32 by mcoulton (and fully agree to the “buy-enterprise-grade” approach) my search goes into a different direction: A low voltage UPS, i.e. buffering my 5V - 12V devices directly. I have a 19" rack so my initial plan was indeed one of the typical 2U inserts - if I would have AC-line-voltage-powered devices it would be my way to go but currently I only have low-voltage devices and my question is:
Would it make sense to have direct low-voltage UPS? Would it save energy/tech overhead instead of using AC, transforming it to low voltage, storing in a battery, making AC again, transforming it up, transforming it down and having the same voltage as in the battery?
For my devices that are between 5V and 12V and use a typical of 5W even a small pack of 18650 rechargeables would provide enough power to get at least some notifications (pure “outage yes/no” would be sufficient) and allow for some essential communication.
Compared to a setup with a traditional mains-power UPS and lots of power supplies behind it:
Pro:
DIY effort
Less wasted energy?
Cheaper?
Energy can be focused on most important devices (as far as they are same voltage)
Core devices like internet modem can be upscaled (more batteries)
Con:
Ready-made
Remaining energy equally distributed to all devices
You’re missing a couple things from your pros and cons (which are flipped for me btw)
Supportabiliy and Maintenance.
What happens when it blows up? How are you getting back in business? Are you building two?
I dont know about you but if I put it in my rack it’s because I cannot tolerate more than a short outage. Everything in it I know pretty much how much time it is to recover worst case even if it completely catches fire. (even the rack itself)
Im also not convinced about cheaper - UPS are dirt cheap, save energy maybe but at the end of the day Ohms law is Ohms law and the efficiency is just a little heat loss
DIY learning project - cool! But I’m not trusting something that needs to be racked to DIY. I’ll save that for something else.
Nope I’m plugging a standard 1/2u ac plug rail into the ups and driving them that way. (edit, I also found at least three 1u usb hubs on Amazon at various price points if I had that much 5v that’s a good option as well)
Yes, the “Con” list was “benefits of a ready-made box” and yes, even in case it catches fire and my house is burning down it is better if it was a purchased device. And as mentioned up-front, I am 100% the “buy enterprise grade stuff” guy simply because of reliability, supportability and maintenance.
So yes, maybe it is just better to get a 2U rackmount UPS and plug in all the devices whatever voltage they need.
The original name seems to be DC1018p, some sellers claim that there are two different versions (1A or 2A for the 12V and regular 5V out) and some videos claim that it can be integrated into HA.
Update: There are in fact several versions of this box, most important differentiation criteria are
Max. combined output in Watt - there is the DC1018 version with 18W and the DC1036 with (would you expect it) 36W
“PoE support” for the DC10xxp model - PoE is is brackets because you can select either 15V or 24V - which is not really the 48V you would expect but your device may run with it anyway. E.g. my PoE webcam accepts standard 48V PoE current when powered through ethernet cable but when powered directly, it uses 12V so presumably it would run with 24 or even 15V PoE.
The most commonly sold version is the DC1018p. Feedback seems to be rather positive, while some vloggers immediately opened the box and found not the expected 4x2.600=10.400 but 4x2.200=8.800 batteries in it. Some did, some not, and TBH this would not break the deal for me as the 3.400 (which are best-bang-for-the-buck) would give it 13.600 anyway.
The “HA integration” in some videos mainly consists of “checking is mains line is working” through e.g. doing a ping through a non-protected device and/or monitoring the health of a mains-connected device. This for sure is not comparable with NUT monitoring but it would give you a notification if there is an outage.
Compared with individual Mini-DC-USVs:
Pro “combined box”:
ready-made box that gets no structurally negative review, plug it into mains and you are set
flexibility of USB/5V/9V/12V/PoE output
Pro “individual mini-USVs”
Battery capacity really reserved for the connected appliance
Energy-saving “pipe through” mode possible as they are “voltage in = voltage out” in comparison with one box that always has to transfer up&down
