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ESR's Newest Project: An Open Hardware/Open Source UPS (ibiblio.org)
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."
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.
This is one of a plethora of currently closed-source products that could stand some competition! Ignore the nay-sayers, of which there plenty, and continue to push the boundaries. We need guys like you, whether we know it or not...
There's hundreds of programmable computers platforms out there, you're just not looking hard enough.
#DeleteFacebook
In fairness, you're obviously not a technical person so your comment comes off as a bit snarky.
The exposure of this project is oriented toward programmers and electrical/mechanical engineers, not someone like yourself who runs Windows to play solitaire and browse Yahoo.
Nothing wrong with that, mind you, just that your comment is coming from a consumer perspective vs /. being a technical oriented site.
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.
Maw! Fire up the karma burner!
Or replace the replaceable batteries, like you are SUPPOSED TO DO.
Sigh.
Shouldn't we be working on an open hardware/open source FedEx instead?!
#DeleteFacebook
It's all about the batteries. You can get a <$100 UPS which will last 2-3 years and keep a PC going until you can do a graceful shutdown, assuming you're in front of it. Then spend $40 for a new battery or buy a new one to get a few more years.
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.
"National Security is the chief cause of national insecurity." - Celine's First Law
Turns out APC already makes them with lithium batteries and Linux talks to most of them already.
.
Let's do this!
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.
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.
8 of 13 people found this answer helpful. Did you?
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 want to run when you shut down.
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.
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.
If he want to optimize for durability and longevity he should use nickel-iron batteries.
It is often used in backup situations where it can be continuously charged and can last for more than 20 years.
Ceci n'est pas une signature.
I wired my PC to run directly off of a 12v battery and leave the battery attached to a charger at all times. Seems to work fine.
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.
There's already a product 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.
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.
politicians are like babies' nappies: they should both be changed regularly and for the same reasons
I use a Synology raid (it has a 12v power brick), a Lenovo PC (with a 12v brick), a router (again a 12v power brick).
I don't need or want a big box that beeps and needs constant maintenance. I want a battery pack using disposible Alkaline batteries that sits between the power brick and the power input and cuts in when the mains power dies. It only needs to last 10 mins, that's pretty much the longest power cut we've had.
I'll stick a few of these on devices sensitive to power cuts and change the batteries when they test bad (should have a 5 year lifespan).
UPS's suck, the battery fail indicator never comes on until they are under load, so you can never rely on them. They die regularly. They beep like crazy, and support legacy crap like serial ports to notify the servers and telephone sockets..... is this the 90's?
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) is Powerwall 1, at 6,4 kWh / 2kW ($3k). Powerwall 2 is easier to get, but is even further out of spec for you (13,5 kWh / 7kW peak / 5kW continuous, $5,9k). #1 would run your computer for nearly 3 1/2 hours, while #2 would run it for over 7 hours.
I'm sure that there's some "middle ground" li-ion backup products out there, though. I assume you want li-ion for the longer lifespan and higher peak output of a properly managed li-ion pack?
"Lock and load, Brides of Christ!"
Whilst I don't want to appear negative and I wish this project well, I can't help observing that whilst the maker and free software world is full of very talented people when it comes to writing delightful user interfaces and making LEDs blink on and off, the heart of a UPS is some serious power electronics.
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 inverter isn't efficient then users will end up spending more on extra electricity than they saved by not buying a UPS from an existing supplier. And this is before we come to the very considerable question of safety!
Of course, the power electronics could be assembled industrially and then sold as something to which you add your own batteries, Arduino and case but then we have some thorny questions:
- Will these modules need to go through formal safety and EMC approval (an expensive process)?
- Are there going to be different versions for different power levels and if so how many?
- Is this project for North America only or will versions be needed for those parts of the world with 220-240V?
I suppose that a half way house would be to supply bare PCBs and perhaps specially made inductive components and let people assemble it themselves. I think that in most parts of the world this wouldn't require any paperwork (electronic components are usually just that - components). In such case I am sure a web page would soon spring up tracking the number of electrocutions and fires! Probably best to get the PCBs produced and sold from a less litigious country than the USA!
1) skip the fucking usb. Go with network. Or at least allow a usb/network adapter. 2) 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 so inefficient. Instead have 48V connector and let power supply take it down. 3) ideally, rack mountable.
I prefer the "u" in honour as it seems to be missing these days.
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.
Already exists, it's called OpenUPS and NUC-UPS. In fact OpenUPS is pretty close to what ekr is proposing, only it already exists as a finished product. Guess he didn't do much Googling before he came up with his one...
The problem is the batteries. Lithium batteries have a distinct disadvantage in that they can die of old age - so even if you never experience a power failure, after a couple of years, the batteries have degraded, just by being 2 years older.
Lead-acids do not have this problem, but they do have problems when they're not treated right, which shortens their lifespan. Basically a lead-acid's lifespan is determined by its use - the more deeply you discharge them, the shorter their lifespan. That's a big difference between the ISL batteries in your car (ISL - ignition, starting and lighting) and deep-cycle batteries. ISL batteries are designed to offer high currents for short periods of time (i.e., ignition and starting), but cannot take much discharge. Even in the deep of winter, a heavy start of a modern computer-controlled car will take less than 1% of its capacity, delivered over the 30 seconds it takes to crank. But don't you dare run it below 50% or you will run into problems.
Deep cycle batteries are designed for lower peak currents over a longer period of time and can tolerate deeper discharges. (But none can take to 0%).
Unfortunately, a UPS demands both high peak currents and deep discharges, so either kind of battery is poorly suited.
Lithiums are great, but with their limited lifespan, are really not suited for standby applications - they really hate sitting on charge continually. There's a reason why lead-acids are still around, and still used in a lot of standby applications. A float charger is dead simple, they tolerate that well, and if you design it right, the standby load can be low that it really doesn't tax them.
The last UPS battery I had, I realized I had changed 10 years ago before failing last year.
There's someone still actually using Google+? Astonishing!
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.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
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.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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.
Learning HOW to think is more important than learning WHAT to think.
Starting a fire by putting two batteries in series? I don't even know what to say beyond, "go back and take elementary school science".
You must live life like a scared rabbit.
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.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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...
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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.
Oh, no! You have walked into the slavering fangs of a lurking grue!
He posted about this exact thing if you want to get some insight into the reasoning.
The real-time aspects will still be handled by a microcontroller.
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 APC does not) is catching a hot battery. I've seen on 2 occasions over numerous years/UPS's where the batteries will get very hot to the point of deformation. When I catch it, I pull the battery clips if I can, pull the plugs and take the UPS outside in case the batteries catch fire.
Or maybe you should broaden your definitions of "computer platforms" and "programmable" a little bit.
#DeleteFacebook
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 culminated in the Raspberry Pi. I felt like many of these products exist to help introduce pure software people (like many here) to the world of embedded programming.
Meanwhile, Arduino is kinda doing the same thing from the other end. It runs on a more typical microcontroller, but it provides a simplified development environment to help introduce hardware people (okay, or anyone afraid of big scary platform SDKs in C or assembler) to embedded development.
I put them in parallel to increase the amper
Is that how that works?? ;)
There've been 12v DC-to-ATX adapters for a while, typically used with car PC's. They let you dispense with the power supply.
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.
"Lock and load, Brides of Christ!"
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
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.
"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.
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...
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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...
https://www.ryobitools.com/out...
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.
That should be Turnigy, not Turnkey. Darn autocorrect.
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.
If you want a vision of the future, imagine a youtube comments section scrolling - forever.
Who the hell uses a 150W monitor?
Every time I spend five hundred bucks on a replacement battery for my APC UPS I had the same thought: isn't there a better way to be doing this?
UPS are needed only for desktops because they allow about 5 minutes of power to do an orderly shutdown. Laptops have their own "UPS".
But, there is another way for both Desktops and laptops. I run Btrfs as my root filing system. I can take nearly instantaneous snapshots of my system on a regular basis, and continue working while those snapshots are sent to an external drive or remote server for offsite storage. Recovery takes less than 3 minutes, unless the sudden power outage caused permanent damage to the hardware. Even then, after the damaged components are replaced a restoration takes less than 3 minutes.
Running with Linux for over 20 years!
And 0,25s is the stated maximum time to full power. The powerpacks (which are basically giant powerwalls) in Australia have been reacting to power fluctuations starting a couple dozenms after power drops out, reaching full power output in a bit over 100ms.
That said, it'd be nice if they could get those times down to under 10ms.
"Lock and load, Brides of Christ!"
Every time I spend five hundred bucks on a replacement battery for my APC UPS I had the same thought: isn't there a better way to be doing this?
Yes. Replace the APC UPS with one from another manufacturer.
APC UPSs are complete and total shit.
I can confirm that. Even the test button beeps and gave the appropriate light signal, but when an actual power outage occurred the APC UPS went down with the desktop. I was running SuSE 6.3 at the time and it turned out that the sudden power outage didn't cause the loss of anything, so I unplugged the UPS and put it in the garbage can. I had many power failures while running my Linux systems and never lost a byte on reboot.
One of the features that helped me convince the dept where I worked to switch to a Linux system for a BBS tax system was during the demo I was asked what would happen if the power failed. (Power failure and crashes were plaguing their Windows + Wildcat BBS, especially on weekends, when someone in the IT department had to come in and reboot the Windows desktop.) "Like this?", I asked, as I pulled the power cord out of the wall. After plugging it back in the system booted up to the menu without problems. It was in operation for 18 months without a single software or OS failure, even though power in the building failed several times during that period, and then it was outsourced.
Running with Linux for over 20 years!
P.S. The DeWalt Portable Power Station is really, really close. I have no idea why they don't allow it to run like a UPS.
"In this case, the SCIENCE dictates that a fire is in fact a very real potential." The science? Me thinks you don't know what the fuck you're talking about.
It makes more sense just to dedicate an inverter to each load which needs one... and use OpenUPS. Only being DC isn't a problem now that inverters are cheap.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
The words "makerspace" and a UPS using mains AC and high current DC don't really go together to be honest. I've seen "makerspace" designs that are just waiting to electrocute someone [water pumps in the box with electronics, stripboard for AC etc].
It does strike me as it's being looked at as a software project first which is the wrong way round. I also can't see how they can deliver something like that cheaply to be honest.
Finally - more and more people are using laptops and tablets which sort of already have a UPS inside - it's called a "battery"...
This is how I have my rpi board setup too - running off of batteries/charger. Except the batteries are 16650(??) lipo...something standard. That was a while ago too.
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.
At 50Hz one cycle is 20ms, I think it's difficult to get much below that, unless you go line interactive. 100ms would be fantastic though.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
ESR: the only "hacker" who instead of compiling code, always compiled and republished "The Hacker's Dictionary"?
The more internal resistance a device has, the more it's going to heat up when current is forced through it.
If it heats up enough, it might be an ignition source.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
Rigol DS1054Z has its flaws but there's simply no way you're building a 4 channel 100MHz digital scope with network interface and usable GUI for 400$ yourself.
You get a 100MHz DS1054Z for ~$400 only if you don't pay for the unlock license and instead steal that capability with self generated unlock codes. Who knows if some future firmware obviates your ability to steal it.
Maw! Fire up the karma burner!
Like what? What are these options? Why would you need to add them on? Just put them ALL in! Unless you want a Tektronix 500-series and all the plugins.
Do you live in a cave? What is wrong with the Tektronix 7000 series?
I would not mind a sampling option for high bandwidth and instant overdrive recovery. I went as far as to design a low cost DSO to support it but decided competing with the cheap Chinese DSOs would fail due to marketing even if their product is broken.
Has anyone ever collected on damaged equipment plugged into a UPS? I figure the rate of occurrence is incredibly low, the flaming hoops that you have to jump through to collect are incredibly tight, or the depreciation on equipment heavily discounts the loss.
I'm not that impressed with disk drive warranties either. I've seen drive replacements that amount to a discount off the nobody-pays-this-list price of a new hard drive, ending up no cheaper than the street price, or an offer of a refurbished drive with an unknown past.
Does ESR really consider UPSs to be the 'next big thing' as ever more users transition to devices with built-in batteries (laptops and tablets) from devices that would benefit from a stand-alone UPS (like a desktop or server)?
So I guess the goal is 'everything open source' and then we won't need manufacturers, we'll all just download WIKI-how pages, round up some raw materials, and head off to a makerspace to build our next cellphone or TV set?
Ken
The other, less dead, batteries forcing current through it will cause it to heat up.
It's like electrical friction.
I see even classic Slashdot is now pretty much unusable on dial up anymore.