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 General questions - what UPS fits best for your use?   Started by SteveA   2026-06-01 21:40:19 +01:00   Comments: 2    Viewed: 28
Tags: dc  mutli-device  ups

  1. SteveA
    SteveA Member
    Hi,

    I have a dozen (relatively) low current devices - each powered by a 12V DC (max 2A) 'wall-wart' PSU.  A few years ago, I used a multi-socket extension to power them all from a (second hand) Eaton UPS.  I replaced this with an APC "Easy UPS" - but this has not lasted well - after a couple of years, the UPS reports an 'over current' fault no matter what is plugged into it as load.  I accept that this might just be a failed battery - but I was never very satisfied with the APC UPS because it provided no mechanism for my PC to react to power events.... In the event of a power cut, I'd be fine if it was only for a short duration - but for longer outages the battery would eventually die and I'd be left with data loss and time consuming recoveries on restart.

    My devices include 2 'Mini PC' (Celeron, solid-state only storage and no monitors); 2 ASDL-modem/routers; 1x Router; 1x Ethernet switch; 4 x 3.5" external USB hard disks; 1x 3.5" external USB disk; powered USB hub.  I want them to run uninterupped 24/7... I've limited budget but I'm aiming for the most robust/reliably solution possible.

    I've come across various DC-output UPS... which are an appealing concept.  I imagine a lot of inefficiency in my old UPS taking its internal battery (presumably 12V) to run an inverter to power 12 PSUs each converting 240V mains to 12 volts again.  Besides the perceived inefficiency, connecting a dozen wall-wart style PSUs to UPS output is clunky and cumbersome.

    I am imagining a single box, acting as a DC UPS with a dozen 12V DC outputs - each supporting a maximum of 2A... and running my dozen devices directly from the UPS without any of the supplied mains -> 12V DC PSUs.  Do such things exist?

    If such things aren't available off-the-shelf, would it be feasible to make one from components and put them in a box myself? (Assume basic electronics knowledge - without any substantial expertise.)  I've seen videos about people doing this on Youtube... However... their DIY UPS tend to support only one or two devices... and none that I've seen support notifying a PC when a power-status event happens at the UPS (e.g. mains input from on-to-off - or vice-versa; battery power significantly reduced - expect ~10 minutes more power.)

    Are DC UPS a viable strategy in a situation like mine - where there are ~12 devices each requiring an uninterupted 12V supply at < 2A?

    If so, can anyone point me at a potentially suitable DC-UPS?  (They seem to be marketed as "mini UPS" - perhaps I need one that is larger but works the same way?)
    SteveA, 2026-06-01 21:40:19 +01:00
    #160
  2. NB-23
    NB-23 Member Warrington
    Howdy

    I have thought about this inverting for the sake of it too
    Mains comes at 240, your UPS internals are at 12V (on small units) and then the UPS inverts it back to 240V AC only to be immediately turned back to 12V DC by the moulded plug power supplies of small electronic devices.

    Google realised this when they made their first data centres - They removed the need for 5v on their motherboards and had small 12 volt lead acid batteries in each server (which were interestingly low powered, made up for by the quantity of them). I remember a photo showing one of these with a battery in the case unfortunately I cant find it now.
    Anyway you are in good company thinking of the DC system like this.

    To your questions:
    We've not had any UPS with the 12V DC output socket yet.
    We've had some devices with 24V DC output - APC CSH2 (for the surface hub2) but that wont work for you - wrong voltage and also it has no AC output.

    I think what I'd do is get a standard UPS for your computers - something like an APC 1000 tower
    https://secure.ups-trader.co.uk/tower-ups/97-sua1000i.html?search_query=sua1000i&results=3
    This has USB for your computer, or you can add a networking card if you have more than one device
    https://secure.ups-trader.co.uk/network-cards/67-ap9619.html

    you can use your existing multi socket extention to add your 12V routers.

    This gets you protected and gives time to tinker. I'd go back to basics - get a 12V battery, a low power charger and see if that is good enough for your loads. The risk is that the voltage under charge (14.5V) would be more than the devices can tolerate. It may well be that in spite of the inefficiency as we are talking about low power devices, the savings are not worth the cost or material of a dedicated 12V system, but it has value just for being interesting. 

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    NB-23, 2026-06-02 10:22:25 +01:00
    #161

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