Then just post instructions online and have L1 sell parts in a kit and have people make the kit. I belive that woud bypass the
Yeah, kind off would.
Selling part kits that can be connected to the mains requires CE to be legally sold in the EU
Edit: How does soldering ~560 points sound? And if you mix up two, you may burn your house down. Or missing one antitracking slot in the main inverter PCB will make your PC explode.
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Wouldn’t the kit just have to include a CE certified receptacle ( probably the wrong word ) ?
Does not sound good. And would create a huge barrier to entry.
Just gonna put some chemistry down in the post for consideration -
LiFePO4
NiZn
Those are maybe the best choice right now however both have their problems.
Also if you are trying to make a good ups then active line regulation circuit should be part of it.
Also filters. … filters evrywhere. …
I don’t want to discourage anyone but the whole task is really hard.
I agree, especially if the target price is $200.
Concerning replacements, are there any other types of mass-produced battery that would be suitable? Marine deep cycle, maybe? A battery that is produced in larger runs by a third party could be a better value proposition if it can be adapted without a loss in efficiency.
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@wendell, I don’t know your background in electrical engineering but coming from experience, there is a lot more you have handle outside of just what battery you should use.
Lithium based should be fine. Panasonic batteries are the most reliable for high draw scenarios, however you need to engineer a bypass circuit for when batteries are at the right voltage, design another circuit to sense voltage drop on mains, an inverter to convert to ac, then you have to deal with square waves and the headache of making sure the ac circuit is clean.
On top of this you have shipping issues with lithium batteries of the size you would need being illegal to ship to a large proportion of countries. Then you have the two main standards of AC power. This is really a job for a proper engineering team. There is so much that could go wrong. You would need years of testing to make sure the product doesn’t malfunction destroying hardware it’s connected to down the road.
Even a 0.1% failure rate which is good could lead to expensive damage and potential lawsuits. Especially if you don’t meet regional legislation of which is another can of worms.
You forgot it is also potentially lethal voltages. I agree in principal but it isn’t something I would undertake without OEM support. The Panasonic cells you mention have a full and complete “ideal” reference design complete with charger, over current protector, safety shutdowns, etc. Not suggesting we not use reference designs where applicable. I don’t exactly propose to do this from scratch starting from nothing.
It might be possible to retrofit super capacitors in leiu of sealed lead acid batteries, for example, with minimal modification of a consumer ups. Don’t know. But I want to find out.
Oh, and Eric has a few proper engineers interested as well in case we need to get really crazy. I am liking nonservians Edison battery suggestion though. There are modern versions of those that aren’t completely ludicrous in price…
I like this approach too. The apc “smart” ups used to be good about this. Could just replace cells every 2-3 years. It’s pragmatic. But I know of no good ups that would be a good starting point or that could be augmented with e.g. an arduino cell health monitor
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That’s why I reckon it would be good to focus on the logic, controller and form factor stuff. It’s more up the general nerd alley and where some significant gains could be had.
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When I was in the HVAC industry I was in telecom CO buildings a lot, and they had massive banks of huge batteries for their 48v systems as backup. Each battery was 2 volts, and I want to say they were calcium-something. I can’t remember. Old technology at any rate. I took pictures one time because they looked cool. I also worked with VFDs (variable frequency drives), which use a sort of super capacitor type system.
Unfortunately battery technology seems like it is pretty stagnant at this point. Super capacitors may be a cool idea, but they have to be able to replace (and replicate) sealed lead acid technology. If they can, then price becomes a factor.
I agree with @tjw, we may need to figure out exactly what the current UPS does poorly and figure out solutions to those problems.
ATTinys are plenty powerful. In case we run out of GPIO pins on an ATTiny, there are always low end ATMega chips to use.
Hi so the short answer is APC and the like overcharge batteries which fries them quickly.
The other short answer is you’re just not going to get battery longevity without going big. We really like 12v sunlyte batteries at work. They’re decently priced, hold up pretty well, and are about as big as a car battery.
The longer answer is true battery longevity is achieved through using flooded lead acid batteries where you have to manually maintain electrolyte levels. Since you don’t want to spend 99999 dollars, using a bunch of huge 2v cells isn’t really feasible because they’re both super heavy and the cost adds up quick.
So we end up having to solve it the other way, through better inverting/charging.
At work we do this the easy way, we run DC wherever we can, and use a DC charging system. For AC, we use a quality inverter you’d find on something like a boat.
For DC charging, it can’t possibly be that hard to source a decent charging IC that either lets you set voltage through pots or whatever, or doesn’t fry the shit out of batteries.
For inverting back to AC, it’s more complicated. To run a computer, or more likely a computer/monitor/etc/etc. It’s HUNDREDS of watts. That doesn’t seem like a lot, until you realize that 500W is closing in on 50A DC pull off of a 12v battery. Small batteries just cannot provide that much power for any length of time. Car batteries can’t really pull that kind of power either. There’s also the problem of huge vdroop under load, which is generally solved by huge caps in the inverting circuit. What’s the solution? I don’t know for DIY people beyond find a used boat inverter/charger and use real batteries.
Using GPIO to monitor battery levels and whatnot is not hard. Voltage shunt into an analog input, doneskis.
I’m rambling some but I deal with this crap at work all the time and we haven’t yet found a somewhat reasonably priced solution.
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soooo… im not even going to pretend to have any real knowledge in this sort of area…
But… Has anyone considered using the same type of batteries you would normally find in an average house-hold Solar system??
I know houses are usually driven off a large battery unit, but those units are comprised of several ( usually multitudes of 10) batteries, linked together…
By my reckoning, a single battlestation on its own, should only require at most, a small fraction of the power draw for an entire household…
I found this an interesting read… especially the part about saltwater batteries, which i now feel the need to look into just cause im fascinated by the concept…
https://www.energysage.com/solar/solar-energy-storage/what-are-the-best-batteries-for-solar-panels/
These are different from car batteries that give massive amps for a short time for spinning a large 6 lier v-8 on a cold day.
Deep cycle batteries are desighned for trolling motors that run for hour on end.
Seriously, doesn’t anyone go fishing, like in real water with real fish? 
just kidding
Then a dc to ac converter, would be nice if PC PSU’s had a jack for 12v dc input
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you know i had honestly forgotten… its been that long since i took the boat out 
I also wonder how difficult it would be to just let the buyer source their own battery? would seriously cut down on shipping costs… Although i guess not alot of people are like me and have easy access to deep cycle marine batteries…
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Using straight DC so you could go power source > charger > batteries > DC PSU > computer works. I run a pair of 50AH gel cell batteries with a solar panel and it can run an Atom based computer for years.
Like anything running off of batteries, the name of the game is to reduce power consumption. I was able to bottom out the voltage of my CPU and substantially reduce my power usage without any loss of performance. I’m considering the new AMD processors with iGPU for my next machine since I could probably drop the voltage quite a bit with little or no reduction in CPU speed. Something like this would work well for many people under a lot of scenarios and could run a decent amount of time from a relatively cheap UPS. Running a gaming rig full tilt would need a substantially more expensive UPS, and if the internet goes out then many games go down with it.
A lot of people simply don’t want to change the way they currently consume power and providing batteries and hardware (inverters, cables, etc) for large power draw systems is expensive. Breaking it up in to separate replaceable units would probably cost more to start and end up cheaper in the long run. I’ve seen a lot of clusters set up this way where they run Pico PSU’s or small DC devices like Pi’s off of batteries charged by a wall charger. If you want to run large systems off of batteries then we need a Pico PSU that is much larger. Or perhaps a board to plug in several of them to power a system.
This.
I already have sub $200 UPSs that hold my server and gaming PC for >30 min. They use 12v7ah and 12v12ah lead acid batteries. They’re easy to replace and inexpensive.
I’d want something that I can toss another battery on when I add a server.
I think better controls and info feedback, scaleable charging circuits, battery monitoring and testing, signal monitoring for input power and inverter output. Tracking power consumption would be nice too. Controlling by a rPi would be cool as we can log, notify and have a web gui for config and monitoring.
I setup controls and monitoring for data center UPSs. I think I have some documentation for Eaton and liebert units if you’d like. Most of what i have is on modbus and bacnet communication but I may have some operation manuals.
Sourcing batteries locally makes international shipping much easier as well. Having a UPS with power conditioning would be a nice extra. Don’t forget 50 and 60 Hz
And 120/240V
Battery+ generator, can’t beat it.
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