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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 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
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.
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.
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.
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...
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.
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.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
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
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