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back to article Rant launches Eric Raymond's next project: Open-source the UPS

In February, developer and open source software advocate Eric S Raymond ranted that the Uninterruptible Power Supply market was overdue for open source disruption, and touched so many nerves around the world that the rant has become a project. Last week, ESR opened up the work-in-progress on GitLab: the Upside project is …

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  1. Charles 9

    It has been my impression that UPS's fail to "off" precisely because they fail to "pass-through", which in their typical actual use case, means they pass through nothing since they're supposed to operate when the mains is out.

    As for power sources, what's wrong with lead-acid? Why not allow us to rig ubiquitous car batteries for the job rather than those tiny "sealed" versions? A case where KISS simpler would be preferred.

    25 2 Reply
    1. Mark 85
      Reply Icon

      Car batteries? Why not have an option for a truck (semi type) battery since they're bigger and have more capacity? So the electronics could once acquired, could be used with the user's choice of batteries including some the monster (and usually ungodly priced) UPS batteries sold for commercial use. The later I think, use a gel electrolyte as opposed to the "normal" acid. The unit itself shouldn't care what kind of battery it is as long as it knows the input voltage/current from the battery and what it's monitoring.

      13 0 Reply
      1. Ole Juul
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        "Car batteries? Why not have an option for a truck (semi type) battery since they're bigger and have more capacity? "

        We almost do already. For my main desktop system I took an ancient discarded APC 300W UPS. So old that I can't even find the manual on line any more. This can run my fairly powerful computer, a big monitor, a router, and a wireless radio. To make this workable, I soldered in some heavy wire to connect a deep cycle marine battery instead of the puny internal one that would have been original.

        As it turned out a few months later there was an emergency with power off for a full 4 hours. I had no time to turn anything off, but when I returned everything was still happily humming along. This is a fairly neat setup and the 110Ah battery was the only expense and cost well under $200.

        As for lead acid, one can argue that it is the best choice because it lasts a very long time and the recycling is very well honed from 150 years of development. Regarding a problem with size, (as someone mentioned above) anyone who does not have 3/4 square feet to spare for a slightly larger than the average car battery is probably homeless.

        41 1 Reply
        1. Jason Bloomberg Silver badge
          Reply Icon
          Flame

          I took an ancient discarded APC 300W UPS ... soldered in some heavy wire to connect a deep cycle marine battery

          When heatsinks and other hardware have been designed only to support the limited backup time the recommended battery gives, extending the backup time with a higher capacity battery may cause problems with that hardware, overheating, fire, or other failures.

          The same too for charging circuits. If designed only to bring a smaller battery back to full charge they may overheat or fail when charging for a much longer time which a larger capacity battery will require.

          Make sure you know what you are doing and have done a risk assessment in case you need to talk to an insurance assessor later.

          11 4 Reply
        2. Anonymous Coward
          Reply Icon
          Anonymous Coward

          > I soldered in some heavy wire to connect a deep cycle marine battery

          Absolutely agree with the views in this, but there is a practical issue, which is that deep cycle wet lead acid batteries really need to gas from time to time. We're off grid, where admittedly the batteries are worked harder than is expected with a UPS. and there are a lot more of them than in a simple 300VA UPS, but when the batteries are charging the whiff can be a rather strong clunk of the egg-and-baked-beans-with-6-pints nature. Theoretically not too good for you, so those who operate on the assumption that any risk is unacceptable would find the wet lead acid option good grounds to exert their power.

          7 0 Reply
          1. handleoclast
            Reply Icon

            lead acid and gassing

            deep cycle wet lead acid batteries really need to gas from time to time

            The gas is from the electrolysis of water, giving hydrogen and oxygen, and usually happens in overcharging conditions (such as the continuous trickle charge in most UPSs when the batteries are already full). Hydrogen can lead to embrittlement in a variety of materials, which may cause unwanted problems.

            In the early days of submarines it was found that the filament lamps in the battery room failed far more frequently than expected. Hydrogen from the batteries diffused rather easily through the glass envelope and caused embrittlement of the tungsten filament, making it more prone to failure from vibration. That glass envelope is sufficient to retain an inert gas in modern filament lamps, or even maintain the vacuum of the early filament lamps, but it won't stop hydrogen.

            Of course, most filament lamps are illegal these days, so you probably won't have that problem. But it's probably a good idea to ensure any area with lead-acid batteries on charge is reasonably well ventilated. I don't know if anyone has done any research on the effects of hydrogen on LEDs, for example, but I suspect it won't do them any good in the long term.

            6 0 Reply
            1. onefang
              Reply Icon

              Re: lead acid and gassing

              "The gas is from the electrolysis of water, giving hydrogen and oxygen, "

              Set fire to it, change it back to water, which tends to not go through glass.

              4 0 Reply
          2. Piscivore
            Reply Icon

            H2S is evolved from charging failing lead acid batteries that have plate sulphation (US sulfation). A healthy battery will generate more H2 and O2 that are harmless unless they see a spark in which case the ratio of each is in perfect explosive proportion. As my crew discovered when they decided to spray the top of a charging 150Ah battery with the residue from an angle grinder cutting steel. BOOOM!

            1 0 Reply
        3. Anonymous Coward
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          Anonymous Coward

          > APC 300W UPS

          APC, nice UPS those, at least for consumer use. Never seen one fail.

          My ex has had one for nearly twenty years now, she's replaced the battery two or three times I think and that's it. It is a bog standard motorcycle battery too, which she replaces herself.

          2 0 Reply
        4. Nobhobbor
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          Deep cycle marine battery is clever, but do they have Electric rental bikes or scooters any where near by because wouldn’t you rather use one or more of those batteries? Don’t lead acid off gas sulfuric acid fumes when charging and produce acid powder at the cathode or anode? I know that after handling a car battery, my clothes developed holes the next time I washed them, I can’t imagine purposely choosing to have that situation sitting right next to my computer if there were better options for around the same price. LiON batteries are recyclable as I understand it

          0 0 Reply
      2. Stoneshop
        Reply Icon

        Car batteries? Why not have an option for a truck (semi type) battery since they're bigger and have more capacity? So the electronics could once acquired, could be used with the user's choice of batteries

        At the very least you would want to adapt the charging circuitry to the battery capacity: lead-acid batteries want to be charged at 0.1C (their rated capacity in Ah), so it's not quite one size fits all.

        4 0 Reply
    2. Duncan Macdonald
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      The big problem with lead acid batteries is that they are BIG (and heavy). (A Yuasa HSB019 12 volt 100 Ah car battery weighs 23.4kg and is 353x175x190mm). Not many home users would consider such a large battery acceptable. For commercial use, large UPS systems normally use non-sealed lead acid batteries (as they are normally in places with maintenance staff), smaller UPS systems use sealed lead acid batteries to reduce the chance of problems such as spillage and acid vapor release.

      Lithium rechargeable cells have a higher power density - but cost much more - to equal the HSB019 battery mentioned above would take about 120 high capacity 18650 cells with a total price several times that of the lead acid battery.

      Given the low power density of lead acid and the high cost of Lithium-ion, most small UPS systems come with small lead acid batteries that are only good for 5 minutes or so at full load. (Big commercial UPS systems are usually sized to cover the period between a mains failure and the backup generator starting up and taking the load. They often do NOT supply the cooling systems but rely on thermal inertia and a fast backup generator startup so a very long UPS runtime is not a desired feature in such a configuration.)

      24 0 Reply
      1. Adam 52 Silver badge
        Reply Icon

        "to equal the HSB019 battery mentioned above would take about 120 high capacity 18650 cells"

        You don't need the same capacity in a battery that can be deep discharged without suffering damage. Still much more expensive, I grant you, but not as much as it appears at first glance.

        3 1 Reply
    3. Christian Berger
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      Well I've actually seen UPSes fail to "off" even when the mains is perfectly normal.

      Those sealed versions are actually far easier to handle as you won't have to worry about acid spills.

      15 0 Reply
      1. Anonymous Coward
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        Anonymous Coward

        "Those sealed versions are actually far easier to handle as you won't have to worry about acid spills."

        But what would you be doing with your UPS to cause an acid spill?

        5 0 Reply
    4. DougMac
      Reply Icon

      >> It has been my impression that UPS's fail to "off"

      The problem I've encountered is that for most of the small-ish UPSs, that when the batteries go past their useful life, the UPS starts cycling the power, even if the wall power has been steady on. APC is particularly nasty about this for certain models.

      Battery past useful life is almost always only a light on the front, I can't tell you the last time I've looked at the front of my home UPS.

      >> Why not allow us to rig ubiquitous car batteries..

      It was covered later to be mostly size. Your UPS would be quite large and heavy. As it is, most small-ish UPSs now use motorcycle/lawn mower Lead-Acid batteries. So, same technology, just smaller package. Less capacity.

      The UPSs I'm mainly interested in though have their own rooms. : - )

      And they do typically use deep-cycle marine batteries. Just lots and lots of them.

      5 1 Reply
      1. Anonymous Coward
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        Anonymous Coward

        "Battery past useful life is almost always only a light on the front,"

        Not in my experience. When the battery fails the auto test, you can see it from the management tool, and even have message sent.

        I'm fine with a small, cheap, easy to replace battery for a SOHO UPS as long as it can shutdown machines cleanly before discharging. If you need to work fully through a blackout you have needs that should be addressed by a specialist - not a DIY UPS...

        3 2 Reply
      2. Charles 9
        Reply Icon

        "The problem I've encountered is that for most of the small-ish UPSs, that when the batteries go past their useful life, the UPS starts cycling the power, even if the wall power has been steady on. APC is particularly nasty about this for certain models."

        Most UPS will cycle the batteries periodically to test them. They keep the mains ready on standby in case the test fails, but the idea is that the batteries need an occasional "stress test" to help cycle them and to make sure they still work. It's when this test fails that the UPS reports the problem.

        My issue is that UPS management software sometimes acts funny. I had it completely drain out an UPS once for no apparent reason which is why I don't hook up an UPS's communication channel anymore and simply go by its built-in display.

        0 0 Reply
    5. Alan Brown Silver badge
      Reply Icon

      "what's wrong with lead-acid?"

      Deep discharge tolerance.

      Lead Acid is cheap/cost-effective and will float forever, but discharge them down to 30% a few times and they're toast.

      Did I mention they're cheap? The cheaper solution than using better chemistry is usually to just use a bigger lead acid bank. There's a reason telcos still use them.

      6 0 Reply
    6. Alan Brown Silver badge
      Reply Icon

      "rig ubiquitous car batteries"

      Lead-acid isn't lead-acid isn't lead-acid.

      Car batteries are designed to be lightweight and provide _enormous_ discharge currents for a short duration (seconds). The lead plate grids on them are relatively fragile and if you deep-discharge them, or use them as leisure batteries (or UPS batteries), they die in short order. (The plates will sulphate up quickly if left discharged below 80%)

      Likewise if you use leisure (caravan) batteries to start your car, you'll get one shot at doing so, then start wondering why the plates are fragmented all over the bottom of the case. These are a better choice for UPS use though.

      Sealed mat lead acid batteries are a good compromise for most UPS purposes as they don't outgas unless heavily abused.

      If you need large capacity, then deep discharge Traction cells are the way to go, but they're not small or light or cheap and you DON'T want them in the same room as the rest of your power electronics (If they boil, every piece of your wiring insulation goes black. I've seen this after a lightning strike blew up a charger on a remote site) and ideally they go in a completely isolated room with good temperature control, nothing that can spark and decent active+passive ventilation.

      In all cases, the float voltage is critical to a few millivolts (and different for each design) Get it wrong and you'll eventually kill the cells whilst spreading acid fumes all over the place.

      Anyone who tries to sell you a car battery for standby power applications doesn't have the first clue about what they're selling (or is intending to make lots of repeat battery sales).

      It's one of the more annoying things I saw whilst spending time in Outer Bumfuckistan, (you could ONLY get car batteries for standby power purposes) along with selling WD40 as "oil" to people who were wondering why everything kept clogging up with gritty shit and needing a constant dousing with more WD40, but still ended up breaking.

      9 0 Reply
      1. Ole Juul
        Reply Icon

        It's nice to see that there are indeed a few technical people here. However it is amazing how many armchair critics there are too. The sky is not going to fall with this kind of project. It's not rocket science, it's electrical engineering 101, and those of us with basic skills will not overlook the problems that some so gleefully predict while wagging their nerdy little finger. Regarding my own project, there is no outgassing, no acid spills, ( I mean really!) and the charging circuit handles the deep cycle battery just fine with an initial 13.7v followed by a nice sedate 13.4v float. The unit does get hot under full load but nothing it can't handle, and this will not happen often as power outages here tend to be in the range of a few seconds and only once every year or two go into the hour range. I put some ventilation holes in the box which seems to keep heat under control. The overall concept is to think things through and be sensitive to what it's actually doing. Assuming that other people are unable to do such things is not an impressive trait to display on a technical forum.

        2 1 Reply
  2. Ian Mason

    Lack of clue

    Yeah, the LiPO battery thing is stupid. Lots of little cells that you need charge balancing circuitry, and cell protection circuitry for instead of a single, big sealed lead acid battery? Yeah, that'll keep down your bill of materials - not!

    The problem is that this seems to be being driven by software weanies and there's no evidence of any power electronics folk's input in the specifications. The fact that they find managing a bypass switch challenging is evidence of that:

    "This may have to be a mechanical switch (possibly flipped by a solenoid, but not a traditional spring-loaded relay that resets to a specific state when power is removed). Implementing the option in software seems hard, especially if this UPS is supposed to protect against intermittent voltages and overvoltages as well (i.e. cases where bypass is the wrong response and there’s no software running due to lack of power)."

    i.e. They have never heard of latching contactors or solid state relays (i.e. triacs).

    Further evidence for the supposition that this is just a bunch of programmers are the facts that the current specification has no, zero, zip, mention of the options for power conversion technology to be used, or the type of output waveform to be supported, or any of the basic questions that an Electronic Engineer would ask first. Like, they've said 300W for 15 minutes (based on measurements apparently) but no mention is made of a figure in VA - probably because they have zero clue what a "power factor" is.

    They need to get some power electronics engineering experience on board very fast or this is going to become another "Arduino Maker Project" designed by programmers. Do that on mains attached power electronics and watch your house burn down.

    58 2 Reply
    1. mtnrbq78
      Reply Icon

      Re: Lack of clue

      I was reading and agreeing with you, but then checked out the project. On the front page...

      We welcome contributors: people with interest in UPSes who have expertise in battery technology, power-switching electronics, writing device-control firmware, relevant standards such as USB and the DMTF battery-management profile.

      So they've got a clue they don't have all the clues.... yet

      25 1 Reply
      1. Martin Summers Silver badge
        Reply Icon

        Re: Lack of clue

        "So they've got a clue they don't have all the clues.... yet"

        Well maybe Ian Mason might want to contribute there and point them in the right direction. All they're guilty of is saying that UPS's suck in their opinion and they want them to be better. If people contributed to projects like this rather than complain about them doing it wrong or not having a clue then they might get somewhere.

        33 4 Reply
      2. Ian Mason
        Reply Icon

        Re: Lack of clue

        Granted, but if you were going to build a house you wouldn't pick out the specific joists to use, and say "We'll leave the rest to the architect/civil engineer/builder, we must get one of those."

        BUT they have already chosen a processor board they would like to use (an A20-OLinuXino-LIME2). In practice this sort of thing doesn't use a Linux based commercial board such as they have picked, but a microcontroller picked to have all the right interfaces for controlling the power electronics. Heck, there are microcontrollers dedicated to power electronics control with much of the control circuitry already there for the taking. That's where you start, picking which of the dozens of MCUs in that space best fits your first iteration of power electronics design, not "Let's have something that runs Linux". That Olimex board costs 45 euro, an appropriate MCU would likely be sub $1 in quantity, and the whole bill of materials for the power control board (including MCU, display, some buttons and a USB connector) ought to come to less than 45 euros. Carry on designing like that and you'll have a 500 euro bill of materials before you've added a case and a battery.

        To be fair, the board is listed on their 'strawman' list, but they're so far into Dunning Kruger that they don't realise how far off the mark they are. Very typical programmer hubris (Says this programmer who just happens to know rather a lot more about electronics than the average programmer).

        37 2 Reply
        1. Justin Clift
          Reply Icon

          Re: Lack of clue

          > BUT they have already chosen a processor board they would like to use (an A20-OLinuXino-LIME2). ...

          Sure. They've definitely jumped onto the bits they feel comfortable with, and obviously have not much clue with the rest.

          However, it does sound like they'd be open to constructive pointers telling them they pieces they need to clue up on. You obviously have depth in areas they lack but need.

          As an idea, maybe point out the electrical bits they need in order to not completely burn their own houses down ;), and see if they manage to get something useful for people happening after all.

          Their skills are stronger in software, so they might turn out to have a decent software side to things anyway. :)

          10 0 Reply
          1. Phil O'Sophical Silver badge
            Reply Icon

            Re: Lack of clue

            They also seem to be asuming that there's only one set of requirements for a UPS. I have three at home, for my server, desktop & TV/satellite system. Well over 99% of the outages I see are < 5 seconds due mainly to summer thunderstorms, or winter snow-on-cables. All the UPSes happily coast through those, no need for anything fancy.

            The one I use to power the server is over-specified, and does link to a NUT monitor process. I get an email when the power goes out, and if it stays out for a long period the server will do a clean shutdown. So far I've had to replace the (sealed lead-acid) batteries once, when the originals lost too much capacity.

            The fancy one that Raymond is suggesting would be OK for my server, but probably over-priced. It would certainly be overkill for the other two.

            To be honest, the biggest criticism I have of the one I use for my server is the amount of power it consumes itself when in standby (i.e. normal mains operation). That will be my primary concern when I come to replace it.

            19 0 Reply
        2. fidodogbreath
          Reply Icon

          Re: Lack of clue

          In practice this sort of thing doesn't use a Linux based commercial board such as they have picked

          "I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail."

          -- Abraham Maslow, The Psychology of Science, 1966

          4 0 Reply
          1. Stoneshop
            Reply Icon
            Devil

            Re: Lack of clue

            "I suppose it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail."

            -- Abraham Maslow, The Psychology of Science, 1966

            I suppose it is tempting, if the only nail you have is ESR, to treat everything as if it were a hammer.

            Me, 2018.

            1 0 Reply
      3. Aitor 1
        Reply Icon

        Re: Lack of clue

        I might contribute to the project as I have the electronics skills, and I am also fed up with UPSs, and I know I am not alone.

        BUT the problem is that designing the right electronics for modern computers is difficult.. we basically need decent electronics.. and that is expensive.

        Read these papers from ABB:

        https://library.e.abb.com/public/58f96070ebc547799c3cae35025f1e85/White_Paper_Power_factor_UPS.pdf

        https://library.e.abb.com/public/525c273041687f0085257bf3005bbf28/ABB-429-WPO_CyberexDynamicInrushRestraint.pdf

        I have seen data centers have fires for not taking these things into account...

        9 0 Reply
    2. Christian Berger
      Reply Icon

      Re: Lack of clue

      Actually are LiPO batteries even suitable for standby use? I mean an UPS battery usually sits around fully charged for years at a time, until maybe eventually it's used. That's not particularly healthy for the cells used usually in phones or laptops.

      9 0 Reply
      1. Anonymous Coward
        Reply Icon
        Anonymous Coward

        Re: Lack of clue

        Actually are LiPO batteries even suitable for standby use? I mean an UPS battery usually sits around fully charged for years at a time, until maybe eventually it's used. That's not particularly healthy for the cells used usually in phones or laptops.

        A modest over-provisioning and planned, automated power drawdown purely for battery conditioning would resolve that. The other important thing about LiPO batteries is that there's a lot of noise at the moment around PV+battery which could provide suitable batteries being made at economic levels of production for this project.

        1 0 Reply
      2. ilmari
        Reply Icon

        Re: Lack of clue

        It's somewhat alright if the battery is maintained at 80% full, alows down the wear and tear.

        0 0 Reply
      3. Jan 0 Silver badge
        Reply Icon

        Re: Lack of clue

        RTFA, LiPO wasn't mentioned!

        1 0 Reply
    3. Anonymous Coward
      Reply Icon
      Anonymous Coward

      Re: Lack of clue

      Well said Ian.

      It appears that they have everything arse about face. They should start with the hardware that does the job and then go on to look at how to control it.

      Without full hardware specifications being well defined everything they are doing is whistling in the dark.

      9 0 Reply
      1. Flakk
        Reply Icon
        Joke

        Re: Lack of clue

        They should start with the hardware that does the job and then go on to look at how to control it.

        That paradigm doesn't seem very DevOpsy.

        7 0 Reply
    4. cantanko
      Reply Icon

      Re: Lack of clue

      LiPo wasn't mentioned - rather LiFePO4 - Lithium Iron Phosphate. Used for traction batteries in many EV conversions as you can beat on them all day and rather than have a LiPo temper tantrum, they just sit in a corner and sulk (and bulge a bit). Very different technologies...

      17 0 Reply
    5. Bronek Kozicki
      Reply Icon

      Re: Lack of reading skills

      Not LiPO batteries. LiFEPO4 - which is a different beast. You make many good points which are probably applicable, but c'mon, confusing these two?

      6 0 Reply
  3. katrinab Silver badge

    Can’t we have whatever is used in laptops as a starting point? They would be a lot lighter, take up a lot less space, and running time would be measured in hours rather than minutes.

    5 8 Reply
    1. Richard 12 Silver badge
      Reply Icon

      Laptops generally produce 12VDC or 5VDC, and consume around 20VDC.

      As they don't produce or consume the 110VAC or 230VAC of a UPS, they are far simpler.

      9 0 Reply
      1. Adam 52 Silver badge
        Reply Icon

        Sounds like a good approach then. Work on a external specification for ELV power and build something simpler and better.

        Rather than try to reinvent the wheel, badly.

        6 0 Reply
      2. katrinab Silver badge
        Reply Icon

        The battery in the UPS puts out some sort of DC voltage. That goes through an inverter to convert it to 230/110V AC. It then goes through a power supply to convert it to 12V DC + 5V DC.

        Would it not be better to connect the UPS to the other side of the power supply?

        3 0 Reply
        1. SImon Hobson Bronze badge
          Reply Icon

          Would it not be better to connect the UPS to the other side of the power supply?

          At what voltage ? The 12V some of my equipment uses ? The 5V some of it uses ? The 7.5V one bit of kit uses ? The 24V some uses ? The 48V some uses ?

          The theory is sound, IF all manufacturers made kit that would run off one standard DC voltage, AND all UPSs used that voltage of battery - but they don't and they don't (the two UPSs I have at home use 36V and 24V nominal batteries).

          It's been an old debate about data centre power - AC or DC with arguments over which is better/more efficient. A lot of equipment runs off 48V nominal (actually 50-something V as it's float charged batteries) as used in the telecoms world - I suspect things might be changing, but traditionally a telephone exchange has a big battery room, some 'kin big busbars to distribute the power, and everything runs off 48V. But use (say) 48V rather than 240V and you (roughly) increase resistive losses in the cables by a factor of 25 - losses are proportional to current squared, and you're pulling 5 times the current. Ignoring losses, your cabling needs to be a lot bigger to handle the current.

          But even if you distribute DC, there's still a power conversion down to the voltages used internally.

          As an aside, while I was at university <cough> decades ago, I was in the computer club and got involved in running a stand at the freshers fair. We were told that we could use mains power (they even switched off the socket circuits) - but they did agree to us using batteries. I had a look inside my monitor and found it used 12V internally, so soldered a couple of wires in, and borrowed my car battery so we could have a working system (this was in the days when computer power supplies were also simple and the one we had could be made to run off 12V as well with a little fiddling). Not quite the sort of battery they probably had in mind ;-)

          10 0 Reply
          1. katrinab Silver badge
            Reply Icon

            That's why I am suggesting that the server manufacturer should provide a built-in UPS function. It would be similar in design to laptop battery / power supplies, except obviously with server grade components, power requirements will be higher, and therefore everything will have to be bigger to cope with it - bigger than a laptop battery / charger, but probably still smaller than the several kg of UPS battery.

            3 1 Reply
            1. Stoneshop
              Reply Icon

              Specs

              That's why I am suggesting that the server manufacturer should provide a built-in UPS function.

              Which would require sufficient room inside the server case for the batteries. And what runtime (i.e. battery capacity -> battery size) would you then aim for?

              Never mind that rackmount servers tend to be rather stuffed.

              6 0 Reply
              1. katrinab Silver badge
                Reply Icon

                Re: Specs

                Have the batteries located where the PSU is currently located.

                Have the PSU located where the UPS is currently located, with a low voltage cable leading to the computer - something a bit bigger than a typical laptop wallwart, due to the higher power requirements.

                Or you could have both outside the case, and a low voltage cable to the computer.

                3 0 Reply
                1. Stoneshop
                  Reply Icon

                  Re: Specs

                  Have the batteries located where the PSU is currently located.

                  You can't use all of the PSU's space for batteries, as you still have to convert the battery voltage to the other voltages used in the system for which you need about one-third of the space a standard PSU takes. For low-power systems (Mini-ITX) you can use PicoPSUs of the appropriate rating which run off 12..18VDC, so easy enough to run off a battery with a charger attached. But for larger systems, especially with beefier video cards, those won't cut it

                  I'm not sure if for those larger systems the reduction in conversion losses is worth it regarding the various stuff you need to do it this way.

                  2 0 Reply
            2. AJ MacLeod
              Reply Icon

              These (servers with built in UPS) have certainly existed in the dim and distant past - Apricot made some (the one I'm thinking of was MCA so that dates it.)

              5 0 Reply
              1. Anonymous Coward
                Reply Icon
                Anonymous Coward

                @AJ MacLeod

                Indeed, back in those days you could even buy the Emerson AccuCard that plugged into an expansion slot on an XT/AT/386. It had a built in battery and with some software was designed to backup to floppy.

                2 0 Reply
            3. Alan Brown Silver badge
              Reply Icon

              "That's why I am suggesting that the server manufacturer should provide a built-in UPS function. "

              Funnily enough, many manufacturers DO provide that option, however it doesn't really matter where the battery is, it still has to be large enough to ride out the outage and you get to pay a premium for such hardware well over and above the cost of using a UPS.

              Of course if you're serious about your UPSes, then you could use a flywheel-based 300kW modular system backed up by multiple diesel generators. They're vastly more reliable than pissing around with battery-based systems (We have about 750kW of such setup, I know of a couple of sites with around 5MW)

              There are parts of the world where unreliable power is the norm. Looking at how the issues are solved there would be a lot more educational than gasbagging about how an idealised UPS would work.

              IE: Battery based systems are intended to only be used for as long as it takes to get the generators running or to safely shut down - and just like generators, battery chemistry/testing/monitoring/alarming is quite well understood already, so reinventing the wheel isn't necessary.

              Just because cheap-arse UPSes don't have these capabilities doesn't mean they're not available.

              Incidentally, one of the most common killers of UPSes I've seen has been dirty power from the mains. Just because volts have come back doesn't mean they'll stay back, or that there won't be a 4000V spike coming in. Even in "first world" countries the standards for electrical supply cleanliless are eye-openingly poor. A couple minutes delay before reconnecting mains is a healthy safety precaution and if it shows the slightest instability in that period, pushing the boat out to 30 minutes or more is sensible.

              4 0 Reply

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