ESR's Newest Project: An Open Hardware/Open Source UPS (ibiblio.org) 232
An anonymous reader writes:
Last month Eric S. Raymond complained about his choices for a UPS (Uninterruptible Power Supply), adding that "This whole category begs to be disrupted by an open-hardware [and open-source] design that could be assembled cheaply in a makerspace from off-the-shelf components, an Arduino-class microcontroller, and a PROM...because it's possible, and otherwise the incentives on the vendors won't change." It could be designed to work with longer-lasting and more environmentally friendly batteries, using "EV-style intelligent battery-current sensors to enable accurate projection of battery performance" (along with a text-based alert system and a USB monitoring port).
Calling the response "astonishing," Raymond noted the emergence within a week of "the outlines of a coherent design," and in an update on GitLab reported that "The response on my blog and G+ was intense, almost overwhelming. It seems many UPS users are unhappy with what the vendors are pushing" -- and thus, the UPSide project was launched. "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. We also welcome participation from established UPS and electronics vendors. We know that consumer electronics is a cutthroat low-margin business in which it's tough to support a real R&D team or make possibly-risky product bets. Help us, and then let us help you!"
There's already a Wiki with design documents -- plus a process document -- and Raymond says the project now even has a hardware lead with 30 years experience as a power and signals engineer, plus "a really sharp dev group. Half a dozen experts have shown up to help spec this thing, critique the design docs, and explain EE things to ignorant me." And he's already touting "industry participation! We have a friendly observer who's the lead software architect for one of the major UPS vendors." Earlier Raymond identified his role as "basically, product manager -- keeper of the requirements list and recruiter of talent" -- though he admits on his blog that he's already used a "cute hack" to create a state/action diagram for the system, "by writing a DSL to generate code in another DSL and provably correct equivalent C application logic."
He adds to readers of the blog that if that seems weird to you, "you must be new here."
Calling the response "astonishing," Raymond noted the emergence within a week of "the outlines of a coherent design," and in an update on GitLab reported that "The response on my blog and G+ was intense, almost overwhelming. It seems many UPS users are unhappy with what the vendors are pushing" -- and thus, the UPSide project was launched. "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. We also welcome participation from established UPS and electronics vendors. We know that consumer electronics is a cutthroat low-margin business in which it's tough to support a real R&D team or make possibly-risky product bets. Help us, and then let us help you!"
There's already a Wiki with design documents -- plus a process document -- and Raymond says the project now even has a hardware lead with 30 years experience as a power and signals engineer, plus "a really sharp dev group. Half a dozen experts have shown up to help spec this thing, critique the design docs, and explain EE things to ignorant me." And he's already touting "industry participation! We have a friendly observer who's the lead software architect for one of the major UPS vendors." Earlier Raymond identified his role as "basically, product manager -- keeper of the requirements list and recruiter of talent" -- though he admits on his blog that he's already used a "cute hack" to create a state/action diagram for the system, "by writing a DSL to generate code in another DSL and provably correct equivalent C application logic."
He adds to readers of the blog that if that seems weird to you, "you must be new here."
House Insurance is not open source, however (Score:3, Insightful)
If a UPS is going to burn down my house, I want it to be a UL listed device. The insurance company is not going to give a shit if I was super careful in putting it together. They're kinda pissy about homebuilt electrical stuff that burns down your house.
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You'll be able to buy quality off the shelf equipment from normal manufacturers.
Re:House Insurance is not open source, however (Score:5, Insightful)
The insurance company is not going to give a shit if I was super careful in putting it together.
Oh wow, American insurance companies only cover you if you use normal off the shelf gear in ways specified by the manufacturer? Do you not have accidents in America or something? Why do you even bother having insurance if it only covers the situations where you're least likely to need it?
Re: House Insurance is not open source, however (Score:2)
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What an American statement. Just sue everyone. Also insurance companies can sell me what they like. What they can't do is dictate what I do with my property. People may think they can, but they can't. About the only thing that they can get you for is intentional insurance fraud. About the only things your neighbours can win when they sue for is arson.
But go your hardest. It's your lawyer money.
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Commercial activities are quite something different. But unless you intentionally built the "burn your own house down 9000" and you burn your own house down, that's precisely what insurance covers. If it didn't cover anything outside of certified equipment then there'd be no point in them existing as someone assumes liability.
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If a UPS is going to burn down my house, I want it to be a UL listed device. The insurance company is not going to give a shit if I was super careful in putting it together. They're kinda pissy about homebuilt electrical stuff that burns down your house.
Does your insurance policy require that electronics carry a UL certification?
Re: House Insurance is not open source, however (Score:4, Informative)
I've worked this on both home and industrial side, and you're technically incorrect. Your policy will state that you meet all applicable building codes as one of the key items,
Stuff plugged into a wall outlet isn't subject to building codes. It's only if it's wired in.
Also keep in mind that UL stands for Underwriters Laboratories, where underwriters verify documentation to accompany a risk analysis for a policy. Insurance companies created UL for this very reason.
For the reason of assessing insurance risk for the corporations building the stuff, not the people plugging it in.
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Stuff plugged into a wall outlet isn't subject to building codes. It's only if it's wired in.
At best, that depends on your jurisdiction for specifics. Your electric stove, microwave, or dryer are not going to be hard wired, but they most definitely are UL listed while your cheap phone charger may not be.
Moving the goalposts, coward. We're talking about what's mandatory, not what happens to be. You're going to have a hard time getting shelf space at a major retailer for a non-UL-listed appliance, but it's not a matter of law.
For the reason of assessing insurance risk for the corporations building the stuff, not the people plugging it in.
Again, no.
That's right. Again, no, coward. You're moving the goalposts. We're talking about why the UL mark was created, not why you might care about it overall. Try to stay on topic, kthxbye.
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If an electrical device (UL or not) is plugged into the mains and results in the apartment complex burning down there is someone to blame -- the landlord or owner, for not maintaining the fuse boxes or wiring, and for not having adequate fire suppression in the floors, walls and especially the ceiling.
I had an outlet on our house stop working. The electrician showed me the cause: aluminum wiring which had gradually corroded the brass screws holding the wiring in. I had him replace all the aluminum wirin
Re: House Insurance is not open source, however (Score:2, Troll)
...a UPS is going to burn down my house
That's a valid concern; it's also a dead giveaway that this project isn't for you. As your concern is no doubt well placed, I highly recommend sticking to electrical items that come pre-built and leave that hobby to those adept enough to assemble custom systems that are far less likely [than cheap Chinese shit] to go up in flames.
There's always a risk somewhere; the trick is seeing things in perspective.
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" They're kinda pissy about homebuilt electrical stuff that burns down your house."
If you'd never do anything wrong, your house won't ever burn down and you'd need no insurance.
Insurance is specifically for when you fuck up.
Re:House Insurance is not open source, however (Score:4, Informative)
Nonsense.
I've built just about everything HeathKit offered, including their color TV, before they went out of business. There was/is NO clause in our home insurance policy that excludes electronic devices built by home owners. It does require that electrical repairs & additions, and plumbing work be done by licensed and bonded journeymen, which only makes sense. Our outlets have safety fuses which blow instantly in case you drop your electric shaver, hair dryer or hair curler in the sink full of water, preventing both fire and harm.
House circuits have 15 & 20 amp fuses which protect house circuits from over heating and fire in case a radio, TV, drill, saw, vacuum cleaner, etc., shorts out.
But, to your credit, if it means anything, you appear to be the first post.
Re: House Insurance is not open source, however (Score:2)
Good on you, ESR! (Score:4, Insightful)
I'm surprised there's not a half-open IP KVM (Score:2)
Raritan's licensing model and lack off VERY simple updates to let older models use this-century TLS encryption annoys me. I wish their was an open, or even half-open, IP KVM. There uses to be one.
I recently learned that one of the top makers of RC plane, car, and quadcopter controllers is open source, with a vibrant community, both in transmitters and flight controllers. That was good news. I can hack the heck out of my RC plane and quadcopter ("drone") now.
IP or RC? (Score:2)
For IP KVM, I don't remember offhand who it was. No longer available, though.
For RC transmitters, Frsky. At least one Frsky transmitter is also sold as a Turnkey. For flight controllers, look at Cleanflight, betaflight, and inav. They are all interrelated, each with a different focus. They run on boards such as the AnyFC F7, which is open.
Turnigy autocorrect (Score:2)
That should be Turnigy, not Turnkey. Darn autocorrect.
Re: Good on you, ESR! (Score:2)
. We need guys like you, whether we know it or not...
Yeah, no shit; I was expecting a slew of petulant, ignorant shits to ask "Who the fuck is ESR??" In addition to his other accomplishments, I seem to recall him being written in to a Neal Stephenson novel; if that isnt geek-cred, there is none. ;)
Instruments (Score:4, Interesting)
There is probably a lot of potential for open electronics instruments as well. Multimeters, oscilloscopes, low end audio and RF spectrum analyzers and such. Dave Jones has had a very well received (AU$ 644,674) Kickstarter project with the 121GW multimeter. It's not entirely open (the firmware is proprietary,) but the hardware is open (schematics, components details, etc.,) the MCU is an easy to deal with STM32 and the programming headers are deliberately easy to get at, so ultimately open source firmware will emerge.
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Who is this “ekr” you keep referring to?
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Jones' meter isn't really open, as the core part that does all the measuring is the proprietary HY3131 chip. It's the same one used in a lot of other low cost, mid range meters. The only bit you can program is the micro that handles the user interface.
What we need are truly open designs that are modular and give the community high quality measuring systems. Anyone can throw one of those HY3131 chips into a project, there is nothing interesting or valuable about that.
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Open Hardware/Open Source UPS?! (Score:5, Funny)
Shouldn't we be working on an open hardware/open source FedEx instead?!
Meh. (Score:3)
Or, you can get a full-blown generator or solar system which will keep the whole house up for possibly days.
The cost and unreliability of UPSs are the batteries. He suggests "deep-cycle marine gel batteries that will last next to forever," which is naive. Marine use is very different than UPS use - cycle life vs. chronological lifetime. No battery lasts forever, and those who want long-term backup for occasional outages (see: voice PBX systems) use flooded lead acid batteries..And that's just for hours - there's a generator involved longer term. Gel cells are better suited for lower current draws over a longer time, and are significantly more expensive than wet cels, per capacity.
What he seems concerned about is getting some warning about impending battery failure. You can fix that by doing regular deep cycle tests, but that shortens battery lifetime and makes for periods where the batteries are drained and you're taking a risk should the power actually fail.
Myself, I have a years-old enterprise class UPS from eBay, assumed the cost of getting new batteries, and will again in a few years.
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...It's all about the batteries....
Yes and no. It is about the batteries (hardware), but it is also about how to communicate with the hardware those batteries service. The UPS is a complex beast. There is a lot of knowledge already accumulated (see the NUT UPS project), but there is also mondo amounts of standardization that needs to be done in things such as APIs to talk with the UPSes.
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Quality UPS units use the USB UPS spec. It's actually part of HID for some reason but whatever, it's an open standard.
On Windows such devices just work, plug in and the driver is automatically loaded. I don't know about Linux, but it should be possible to support easily enough.
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So I want to keep my automation systems running throughout the outage: Internet (fiber with 4G backup), phones (VoIP), fire alarms, security cameras, emergency lights, fireplace. The power draw is about 100W on average, so I need something like 2kWh for my systems to survive through an outage. A traditio
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Seattle's sun exposure is about average for Europe; about half of Europe is sunnier and about half is dimmer. That's not stopped Europe from going big on solar.
If you're talking several kWh, you're definitely getting into home backup system ranges, such as a Tesla Powerwall ("a production-quality UPS with li-ion cells" - you can see the results of fire testing on their industrial scale version here [electrek.co]). And then you'd already have an inverter if you ever did decide to go solar.
Even if you decide that the pay
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https://www.researchgate.net/f... [researchgate.net] - you can see that on average Seattle is reasonable, but it totally fails during winter. And winter is the time of outages when the backup power is important.
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FYI, a "normal" solar install (without a battery backup) doesn't protect you from outages at all, even in the summer. The grid-tied inverter disconnects from the grid; it can only match to an existing waveform, not build one from scratch.
It's the battery backup and the hardware that manages - if you have one - it that lets you keep the lights on when the power goes out; a second inverter, running on the batteries creates a driving signal to mimic the grid after the disconnect, which the primary inverter th
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That was uncalled for. You can add information to a topic without being rude.
Re: Meh. (Score:3)
Possibly naive question: canâ(TM)t the cells be arranged in such a way that you deep cycle test on half the battery at a time, so youâ(TM)re running at reduced rather than zero capacity?
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Battery resistance can easily be trended for each cell or jar, and you have good indication of a pending failure.
The real problem with UPSs is the series(-parallel) combination of lead acid cells leads to the aging of the string being partially dictated by the worst cell. With per-cell battery management system like you need with Li-ion you could dramatically improve battery life.
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Re:Meh. (Score:4, Insightful)
For most a lot of recreational marine use, the usual battery choice seems to be AGM batteries and these usually drive a mix of direct DC loads and an AC inverter.
There are some people that use flooded lead acid batteries, but these tend to be maintenance heavy and that can be a problem when batteries aren't always easily accessible.
I don't think the marine use is any less demanding than a UPS when you consider that driving an inverter is basically UPS use. Much of the time the batteries are under charging current in marine, either from propulsion alternators or due to generator running.
The newer larger vessels seem oriented towards running as much as possible off the inverter. I've seen some larger setups include DC inverter air conditioning due to its low start current requirements, allowing for (limited) air conditioning off the inverter. I think mostly this is for pilot house use when the vessel is under way and is getting power off the alternator.
Solar adoption on power vessels is less than you might expect, but I see setups close to 1500 kw on some new models. But they're still highly generator bound if you want stuff like large air conditioning, water makers, or large appliances like stoves or washer/dryers.
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Point is that the demands are different. Here, I consider "marine" to be a broad term which covers applications where the batteries are used on a regular basis (e.g. RV, off-grid solar, etc.). A UPS gets used infrequently, a power outage isn't even a monthly event for most. Batteries which last a long time on float are called for so the UPS is ready to go when an exceptional event
Re: Give me a 12v battery brick (Score:2, Insightful)
Am I the only one with a $120 APC UPS with $50 replacement batteries every 2 years that does exactly what OP was looking for? And I get 35+ minutes of action time for my network gear, primary computer and one flat panel, complete with usb connectivity that shows up and is addressable in Linux.
Nevermind, just open source it. That solves the problem.
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Does your system do graceful shutdown when the battery runs low? I spent a week with APC, USB ports and NUT trying to get that to work properly.
Does your system show you a nice display of how many hours of protection it will provide at current power load?
The project is all about standardizing all that proprietary gunk and providing the features that UPS vendors haven't bothered to. As you point out, there are plenty of cheap UPS's. It's nt about cost.
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Mine does. Cyberpower 1200AVR is the model I have. It reports curent load in watts and allows me to configure any shell script I want to run on power outage and a separate script to run on low battery level. If I remember correctly, I can also configure what percentage triggers the low battery script.
I'm not sure what you consider a "nice display", but to me a command with text output is nice. It's easy to parse and trivial to put into a cron job and pipe the output to whatever graphing and/or logging softw
NUT UPS (Score:2)
.
Let's do this!
100% on laptop nowadays (Score:2)
Very cool, but I have to admit that I'm 100% on laptop nowadays. I either work at the client site, or in my own office, and decided that I'd rather maintain one laptop instead of two desktops. With USB-C, you basically turn monitors into docks. It's just one or two cables and you go. No UPS necessary with a laptop.
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I think you’d be hard-pressed to find a server room populated with laptops, however.
Fundamental issue is the underlying battery tech (Score:4, Interesting)
Bulk of the consumer grade UPS are based off sealed lead acid - fairly idiot proof but only moderate charge capacity, limited peak draw capacity and limited life (normally the battery capacity has seriously degraded after two years of continuous service).
Making the battery user replaceable would be a big step in the right direction.
Shifting to Lithium Ion cells (preferably the iron phosphate variant) and applying a little de-rating will significantly improve the situation (requires a charge management circuit but these can be easily be sourced). The manufacturers' data sheets state to charge lithium ion cells to 4.2 volts per cell, keep the charge limited to 4.1 or even 4.0 volts per cell will dramatically increase the life of the cells (leave this as an exercise for the reader to research).
If you want to make the equipment "industrial rated" then component ratings need to be reviewed. Capacitors are available in various voltage ratings however if you want the equipment to last 10 years in +100F/+40C conditions then the voltage rating needs to be nearly double the normal operating voltage (there is a study done/sponsored by one of the US military branches on longevity and component ratings).
There is some fairly heavy engineering required on the power side of stuff and I don't believe ESR has yet to wrap his head around all the issues. Perhaps that is why he has put the call out for assistance.
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normally the battery capacity has seriously degraded after two years of continuous service
As someone whose job it is to monitor industrial UPSes at a major hazard facility, let me say: WTF ARE YOU DOING! You should be easily able to get a UPS to run for 5 years unless you're horribly abusing it environmentally or electrically.
Unless you're defining "seriously degraded" as below 90% or something silly like that. Or listening to the vendor's sales guy, that's another expensive mistake.
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Unfortunately, a UPS demands both high peak currents and deep discharges, so either kind of battery is poorly suited.
If you overspec your battery, you can have low (relative to spec) peak current and deep discharges. The trade-off is a gigantic and heavy battery, which you can tolerate in certain situations.
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The reason they use SLA batteries instead of lithium is safety. The equivalent size lithium battery needs careful balancing, charging and venting capability in case of a fault.
It's by no means impossible to do, just much harder than with SLA that will take all kinds of abuse.
There are already lots of open "power wall" systems that provide home energy storage. Most are open (not enclosed) to avoid venting issues, and use off the shelf BMS and inverters. They would be a good place to start though.
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Use power tool batteries. The bigger ones have plenty of energy (18V 5Ah). For many people it's perfectly fine to share a battery between the UPS and an infrequently used drill, which amortizes costs. Ideally one of the tool companies would even pick up manufacturing. There are some multi-battery tools already if you want to really have fun.
https://www.ryobitools.com/pow... [ryobitools.com]
https://www.ryobitools.com/out... [ryobitools.com]
Nickel Iron (Score:2)
If he want to optimize for durability and longevity he should use nickel-iron [wikipedia.org] batteries.
It is often used in backup situations where it can be continuously charged and can last for more than 20 years.
Already shows signs of forking (Score:3)
And as such, instead of a single commercial pressure on the existing UPS makers to up their game, we will end up with a "background noise" of ever-changing, starting-then-fading, projects that become increasingly incompatible. And therefore instead of a united front that competes with the UPS makers, there will be loads of minor players that the big guys can safely ignore.
A better way to approach this would have been to introduce a mature product, build a user base and offer off-the-shelf solutions. Much like with RPi or Arduino (though admittedly, both of those suffer from fork-ism). Rather than to hail the coming of vapourware and getting bogged down in design arguments.
Re:Already shows signs of forking (Score:4, Insightful)
I'll start by pointing out some issues in ESR's current plan.
He is aiming to supply 230W for 15 minutes, which he says will power a "typical desktop system with 4k monitor." It won't, for that you need at least 500W and unless you want to play a careful balancing game more like 1000W. Sure, you system might average 230W, but peak load...
He also wants to use Upverter for electronics CAD. Upverter is a proprietary, web based (!) schematic capture and PCB layout system. It makes no sense at all considering that Kicad is both Free and better in pretty much every way. Kicad and git are a proven solution.
The other issue is lithium batteries. There is a reason SLAs are used, and it isn't just greed. They are cheap, easy to use and robust. You don't really get issues like one bad cell making your whole pack die, or needing to balance them and manage charging carefully. He complains that vehicle batteries last much longer, but they have complex battery management systems that are not at all trivial to design. Cheap lithium batteries like you find in toys and phones only last a couple of years, worse than SLAs.
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He is aiming to supply 230W for 15 minutes, which he says will power a "typical desktop system with 4k monitor." It won't, for that you need at least 500W and unless you want to play a careful balancing game more like 1000W. Sure, you system might average 230W, but peak load...
It might, depending on how much extra hardware you're running beyond a single SSD and whether the system is idle or not.
Peak load is a separate thing, but you don't need to be able to supply 1000 W for 15 minutes to be able to cover 1000 W peaks.
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Upverter sucks, but Kicad is downright user-hostile (which is, unfortunately, quite common for open source software). I'd suggest using Diptrace for schematics and then do most of the the routing in Topor lite.
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I've done multiple projects in Kicad, hobby and commercial. It's easy to use, better than Orcas, CadStar and Eagle.
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Well, being better than Eagle is not exactly aiming high, you know. Both are very clunky and counterintuitive in their own way. I wouldn't want to use either ever again. But I guess you would also rather use vi than a modern IDE. There are people like that.
There is one really good thing about Upverter, though - the full integration between the schematics editor and the PCB editor. If you make changes to the schematics, these changes are reflected on the PCB right away, which makes what-ifs easier (reassigni
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I prefer Emacs actually.
Power electronics is hard (Score:2)
As someone who did a fair amount of power electronics many years ago at University I can see that designing and constructing an efficient inverter for a UPS is a none-trivial task. Further, if the in
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As someone who did a fair amount of power electronics many years ago at University I can see that designing and constructing an efficient inverter for a UPS is a none-trivial task.
The difference between university electronics and real world electronics is vast. At university you are trying to learn fundamentals so you design things like inverters using basic components. In industry you want it to work and be cheap, so you buy an existing chip which does what you need and plonk down the circuit in their application note.
There are lots of inverter chips out there for the solar panel industry, the inverter shouldn't be a difficult part of the design.
Several suggestions (Score:5, Insightful)
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What you are asking for is essentially the open compute design.
http://perspectives.mvdirona.com/2011/05/open-compute-ups-power-supply/ [mvdirona.com]
http://www.opencompute.org/wiki/Open_Rack/SpecsAndDesigns [opencompute.org]
The standard setup is three power supplies in each rack (they are shifting to two with v2) supplying DC power to each server. With one UPS rack supplying DC power to six server racks. No inverter in sight.
Also, Google used to run 12V batteries in every server but more recent designs haven't been publicly release
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The main issue with DC power is that vital peripherals like monitors are usually AC only. ESR wants this thing to be used with workstations.
Re: Several suggestions (Score:3)
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That's not a bad idea. Given that it would be stepped from the battery voltage anyway, making the output voltage programmable wouldn't be hard. There are already 12v and 19v PSUs out there.
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Every panel I’ve ever seen has an internal PSU, because it makes the inverter for the fluorescent backlight tubes cheaper.
Who uses CCL backlights anymore?
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fluorescent... backlight... tubes
I'm sorry, are you from the past?
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skip the fucking usb. Go with network.
That's a terrible idea, and along the same mentality that led to the disaster of IoT. Do you really want to have to apply security vigilance to your frikkin UPS instead of just plugging the damn thing into one of your always-on machines and letting everything else query that?
Or at least allow a usb/network adapter.
Now that I could get behind.
it is long past to have a direct dc line from battery to going past computer power supply. Converting from DC to AC and back is
One problem with off-the-shelf: bad defaults (Score:3)
I have an old APC Smart-UPS 1500 (the black version that Dell sold, bought at a blowout price from TigerDirect back in the day), and one thing I found was that the default hair-trigger response was murder on my batteries, due to a daily power grid switching transient that would unnecessarily trigger the unit for a few seconds. Setting the sensitivity to low made a huge difference in battery life, and another thing that helped was to switch to monthly self-tests instead of weekly. I do a manual battery calibration once a year.
The 1500 is a bit overkill-ish for my setup, but it has served me well.
The software part is easy (Score:2)
So is the circuit design
The hard part is the fabrication
Making a device like this that will actually stand up to years of use requires custom PCBs and a rugged case, with sufficient cooling to prevent overheating
Most software hackers can easily handle the programming. Most people with a good grasp of circuit design can design the electronics
Actually making one that safely functions for years is a lot harder
And yes, I make prototype stuff like thus, but I have a home machine shop
Depends on what you need... (Score:2)
If you just want 30 seconds to shut down a PC, you are better served with a basic, certified UPS. Newegg has several under $75, and a 255 watt one that starts at $39.95.
Think smaller (Score:2)
There's hundreds of programmable computers platforms out there, you're just not looking hard enough.
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Or maybe you should broaden your definitions of "computer platforms" and "programmable" a little bit.
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What did you do, solder some jump leads to the molex connectors and use DC-DC converters for the 5V and/or 3.3V lines?
Every time I go ferreting around inside a PC I wonder if it's possible.
Re: Car batteries in a box (Score:2)
Re:Car batteries in a box (Score:4, Informative)
Or replace the replaceable batteries, like you are SUPPOSED TO DO.
Sigh.
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Or replace the replaceable batteries, like you are SUPPOSED TO DO.
Sigh.
Yep. That's what I do every 3 years. Replace the batteries with higher Ah batteries, if possible. I then re-use the old batteries by hooking them up to solar panels at the camp to run 12v items like led lights. I put them in parallel to increase the amperage and, when the voltage drops to 7V or so, put those batteries in series to provide 12-14v.
Re: Car batteries in a box (Score:3)
I put them in parallel to increase the amper
Is that how that works?? ;)
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Yes, actually. With older lead-acids, the internal resistance increases, leading to reduce efficiency and peak current capacity. Paralleling them up lets you get a bit more life from them.
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It's about time we moved past shitty lead-acid batteries for UPS systems.
Where are my Li-ion UPS systems? Where are my server/workstation 1800 watts sustained over 30 minute battery options? I want my damn server to have enough time to shut everything down. No more of this "suspend to ram/disk", I want it actually shut down, and if something hangs, not sit there at the screen waiting (I'm looking at you windows) for someone to close whatever is running/hung.
and god damn windows et al software updates that w
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Why would you want batteries that have less capacity per dollar? You don't need a portable UPS for a server so using lighter batteries doesn't make any sense. There's a reason other than for a few boutique UPSs that they all use real lead acid batteries.
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"There's a reason other than for a few boutique UPSs that they all use real lead acid batteries."
Exactly, nobody can steal them.
I remember a computer shop once got a delivery of a big one, the receptionist girl said it was OK to put id down just by her desk. As itturned out they had no equipment to move it only a single inch, so the company was called back to deliver it right to the client who had ordered it. That thing weighed a ton.
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A real 1,8kW, not a nominal 1,8kW? At 1,8kW for 30 minutes (after DoD limits, a kWh or more, versus a several dozen to a couple hundred watt hours in a traditional consumer UPS battery), and such a output power need, you're straddling a sort of awkward middle ground between a UPS and a home backup system (such as a Tesla Powerwall). Which is indeed a UPS (plus a grid-tied inverter and other things), although too pricey for your average UPS user's needs since the smallest you can get (if you can find one)
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Can Powerwall act as a UPS? For example, if the grid goes down will it switch over fast enough to avoid your computer rebooting?
I was kinda interested in the Nissan car-to-grid system but the switch over is not that fast. The food in your fridge will be fine, but not the unsaved masterpiece on your PC...
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Hmm, scratch that. A third-party supplier I found cited lower reaction times than I'm finding elsewhere. It appears that Powerwall 1 takes several seconds to switch over, while Powerwall 2 is "under 0,25 seconds". Close, but not quite enough, unless your power supply has some sort of capacitor buffer.
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In my experience a 500W PSU running at 20% load (idle) will cope with a 0.25 second interruption okay. How far you can go I don't know...
Re:Car batteries in a box (Score:4, Interesting)
Already exists, it's called OpenUPS [mini-box.com] and NUC-UPS [mini-box.com]. In fact OpenUPS is pretty close to what ekr is proposing [mini-box.com], only it already exists as a finished product. Guess he didn't do much Googling before he came up with his one...
Re:Car batteries in a box (Score:5, Insightful)
OpenUPS2 and NUC-UPS can only provide about 60W, maybe 100W peak for short periods. And they are DC only, so you can't run your workstation monitor from them making saving your work and shutting down a bit tricky. ESR specifically says he wants to run a 150W monitor from it.
Those little things are great for low power DC servers, but useless for workstations.
Re:Talk vs Action (Score:5, Informative)
There's already a product [mini-box.com] that does this, it's been around for years. Actually there are lots and lots of things like this out there.
The killer isn't designing the thing, that's relatively straightforward ("relatively" meaning you need a couple of experienced EEs, 6-12 months, and $50K or so to get the kinks worked out). What's not straightforward is getting it manufactured in quantity and UL rated. Open source works OK for software where the "manufacturing" cost is zero and there's no need for any safety certification, but less well for anything else.
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Not being an EE, how can the OpenUPS be modified to accommodate 100-240V AC input, and batteries enough to handle a desktop workload -- 23"+ LED monitor plus desktop (not laptop, which already has a battery) computer. I'm thinking the 4 AA-style batteries aren't going to cut it.
Re:Talk vs Action (Score:4, Informative)
Do you mean the OpenUPS? It's DC only, and one of the hardest parts of ESR's UPS is the AC part. He needs it to run things like monitors that typically are not available in DC versions.
The AC part can be designed a number of ways, but from ESR's requirements it sounds like line interactive is required. The simplest way to do that is to take AC mains and convert it to DC. Use the DC to feed a DC to AC converter that produces the output AC voltage, and have a switch over mechanism in case the AC input goes away. Big caps to cover the gap during the switch over period. The DC also charges the battery when required.
As well as providing very good isolation of the output from the input, this method also makes it easier to handle various AC voltages and frequencies. The down side is that it is less efficient and much more complex than a simple switch-over system.
Designing such a system that can safely handle 1000W peak and say 500W continuous is not trivial. Getting it certified as safe is very expensive. Even the equipment to test such a design seriously will run into many tens of thousands of Euros/Dollars.
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He posted about this exact thing [ibiblio.org] if you want to get some insight into the reasoning.
The real-time aspects will still be handled by a microcontroller.
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Given that he uses the phrase "Arduino-class microcontroller" as the token alternative, I feel like he has no real grasp of what a microcontroller really is. "Arduino" is just a hobby-grade software stack, typically (but not exclusively) run on top of certain Atmel microcontrollers (along with certain reference designs) to make them more accessible.
A few years ago, it seemed like every week there was another SBC whose whole claim to fame was that it ran Linux, and they had a Slashdot post. This kinda culmi
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Never built one of their tube kits, but did build some transistor amps from them, eico, dynaco and Hafler. Good memories and one of the things that got me into electrical engineering. Now I tend to build stuff from scratch using SBC's. I do wonder on the UPS though. I could see problems with EMC, voltage transients etc. When power fails, and is restored, bad things can happen. I recall one time after an ice storm the power yoyo'ed for about 10 minutes. UPS survived it. Another issue I hope he tackles (my AP