Author Topic: UPS Supercapacitor Conversion  (Read 24459 times)

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Offline BradC

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Re: UPS Supercapacitor Conversion
« Reply #100 on: December 06, 2018, 11:35:15 am »
I'm still not seeing the downside but the test has a long way to go.

For your specific use case where it's not about availability or graceful/safe shutdown it's probably the perfect solution. What you have is the electronic equivalent of the old motor/flywheel/generator power conditioner. Smooth power and the ability to ride out minor blips, plus isolating your load from the mains just long enough to bring up the generators.
 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #101 on: December 06, 2018, 12:48:48 pm »
Oh it'll last for a long time, don't worry.  It just doesn't have much up-time! :)

Tim
When I started the thread, I was asking for experiences with some of these very cheap capacitors.  While most of the discussions surrounded brands of UPSs and what batteries to buy, my concern is still the same, how will these cheap capacitors perform over time.   I derated them a fair amount for voltage and capacity to try and give them every chance to have a long and useful life.  We will see....

I'm still not seeing the downside but the test has a long way to go.

For your specific use case where it's not about availability or graceful/safe shutdown it's probably the perfect solution. What you have is the electronic equivalent of the old motor/flywheel/generator power conditioner. Smooth power and the ability to ride out minor blips, plus isolating your load from the mains just long enough to bring up the generators.

For the most part,  that is correct.  My goal was never to ride out more than five seconds or so. 

I mentioned early on that the cost of the batteries vs these low cost, bottom end super caps was a wash.  Someone mentioned size but as I mentioned, with the short durations I am looking at, it's a tight fit but the bank is small enough to fit into the UPS.   Some were concerned over the recovery time (how long to recharge the bank after a dropout).  So far this has not been an issue.   Someone mentioned their concern of a fire hazard and the possibility of burning down our house.   The case of the UPS is steel and the caps are well insulated.  I guess a battery could also rupture and leak acid, maybe explode.  I would guess that the case is designed to handle fault conditions like that but then again...

It does seem like a good application for them.  If the system holds up for a few years, I may invest some time in making something a little higher quality than this unit.   

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #102 on: February 17, 2019, 04:31:18 pm »
It's been a little over 2 months from my last update.   We only had one dropout that caused the counter to increment during this time.    It was the typical secondish that we see.  I had been running some long term test at the time it occurred.  The UPS did it's job and rode it out. 

I've left the double conversion active and havn't done anything with it since turning that function back on.    The capacitors continue to run cold.   I have some filter material in front of the unit that is starting to get a bit dirty but no other service beyond the UPU's built in battery test that I have programmed to run.     

I've been thinking that after a year, I will pull the UPS and repeat my dropout test.   It may provide some insight in how these low cost capacitors are aging. 
 
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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #103 on: March 22, 2019, 12:18:54 pm »
We had another large storm which caused another tree to take down a line.  The power company was fairly quick and the generator was only running for a day.   Of course the UPS didn't save me with that one.   The rest were short dropouts like we normally will see and the UPS held up just fine.
 
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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #104 on: May 09, 2019, 12:05:24 am »
A few days ago I was logged onto EEVBLOG, posting some BS and the power dropped for several seconds.   I thought for sure it was going to drop but it still rode it out just fine.  No other power drops to report but it was a reminder that the project is coming up on a year of testing.   The house has not burned down and the caps continue to run cold.   It continues to be one of those boring projects that just does it's job. 

On 6/28 it will mark one year and I will repeat the test below to see if I detect any changes in the hold up time.    No idea what to expect.

I am guessing with a 500W load, if it could ride out 5 seconds it would cover the vast majority of the dropouts we have.  Most of the time, I am using about 200W and I would guess the dropouts are around a second.  It's enough to have the lights flash and upset any tests I am running. 

Looks like it can hold the 300W for roughly 17 seconds.  In the ballpark anyway.   After reading the datasheets,  I had decided to run the caps well below their max operating voltage.   I think the next step is just button the thing up and see what happens over the next 5 years.  I will program the UPS to run a test on the bank every week or so.
 
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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #105 on: May 10, 2019, 12:02:26 pm »
Just a couple of minutes ago, we had another dropout.   This seems pretty close to the same time as the last event a couple of days ago.   Which, come to think of it, the UPS used to frequently beep about an hour earlier (it beeps to indicate an event).   We have this stupid daylight saving time that changes the time zones.   

I wonder if they switch sections of the grid at certain times of the day and if there is something going on with some of their gear.     Maybe next year, make up something better than the pedometer to record events which would log the date, time, type of event and length of dropout.    Maybe there is more to this story than just using the supercaps to ride through these dropouts.. 

Offline BradC

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Re: UPS Supercapacitor Conversion
« Reply #106 on: May 10, 2019, 01:26:58 pm »
Has the ups got an interface? Can you monitor it with something line nut?

I monitor all mine with apcupsd. Really useful to get the emails and logs letting me know when, where and what the fault was.
 

Offline madires

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Re: UPS Supercapacitor Conversion
« Reply #107 on: May 10, 2019, 02:03:35 pm »
NUT = Network UPS Tools -> https://networkupstools.org/
 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #108 on: May 11, 2019, 02:44:47 am »
It has an interface and came with some software but I have never used it.  As soon as I saw it was JAVA based, I discarded it.

So, I just checked and basically it looks like with a PC running 24/7 it could track the times when it switches to the battery bank.  It has other metrics like the input/output  line voltage, frequency, temperature......  Just basic stuff.

It can't seem to collect the metrics I would be looking for.    Ideally, I would like something battery powered, that can record the date/time and length of each dropout, down to a 10th of a second.   

Offline NiHaoMike

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Re: UPS Supercapacitor Conversion
« Reply #109 on: May 11, 2019, 02:54:30 am »
It can't seem to collect the metrics I would be looking for.    Ideally, I would like something battery powered, that can record the date/time and length of each dropout, down to a 10th of a second.   
Old smartphone/laptop, Raspberry Pi, or whatever low power computing platform recording the mains with a sound card connected via an attenuator.
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Offline bicycleguy

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Re: UPS Supercapacitor Conversion
« Reply #110 on: May 11, 2019, 04:20:14 am »
@joeqsmith
Just noticed thread.  In response to first post.  In a Davis weather station sending unit acquired 2005, that sits outside with a 3x4 inch solar cell and a supercap to power the rest of the day.  Failed in 2009 when after about 5 heavy overcast days no signal.  The leads were severely corroded.  Replaced with 2 NessCap 2.7V, 10F from digikey.  Lasted better than 10 years when some other chip failed from corrosion.  The caps are still good looking for a project.  They were discontinued at Digikey but are the same physical size as these 50F ones for the same price today:  https://www.digikey.com/product-detail/en/nesscap-co-ltd/ESHSR-0050C0-002R7/589-1004-ND/946804

I highly recommend them.

Edited:  Just read the whole thread.  Here's some more data.  The transmitter operates correctly when the supercars are as low as .31V.   Typically around 2.6V, but never higher than 2.65V.  Never measured the currents.  At the time I replaced the original cap I didn't suspect electrolyte leakage so didn't check for it.  The ~4x5 inch board is not conformally coated and gets lots of spiders and bug droppings and the 2019 failure was on the main transmitter chip which is only rated for 80% humidity!  (This is up on a pole with the rain gage, temp and humidity sensor, hot days in the sun the caps must be over 90F  90% humidity)  I replaced the original cap with two in parallel with no other circuitry.

To Davis Instruments credit the current boards ship with conformal coating.
« Last Edit: May 11, 2019, 05:28:02 am by bicycleguy »
 
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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #111 on: May 11, 2019, 06:48:36 pm »
Old smartphone/laptop, Raspberry Pi, or whatever low power computing platform recording the mains with a sound card connected via an attenuator.

I have yet to own a cell phone.   :-DD  If I roll something for it, I will just convert the AC to a digital signal and time the pulses.  I could just use the relay that I have today that runs from the wallwart drive it.   

@bicycleguy
A friend of mine gave me a Fluke 189 that still has the original super cap installed.  I've had to replaced a few of them that started to show some oxidation and one that had really high leakage.     

After writing this, I thought  I've had that meter for a while now and had bought spare caps.  Decided to pull it back apart and replace it while I was thinking about it.  Noticed the batteries were low and sure enough.  See attached.   :-DD   All four of my old Fluke 18x's now have new caps.   

On the flip side, I had a tablet that the PCB was damaged beyond repair after the cap leaked after a a few years.  I had two of these tablets and when I looked at the second one, the cap was just starting to go.   

So depending on several factors, the life could be a couple years to well over 20. 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #112 on: June 19, 2019, 12:44:39 am »
It's been almost a year since I started this thread.    Over the past year, the UPS has saved me roughly 20-30 times.   We had 4 or so outages that lasted more than an hour.   There was really only one time that it dropped out and had the holdup time been even 10 seconds longer,  it would have rode it out.   All in all, I have been pleased with the results. 

As promised,  I have repeated the 300W holdup test using a resistive load (incandescent lamps) and the UPS set to 110V 60Hz double conversion.   If I reapply power right after the system shuts down, wait for the output to enable and immediately remove the power, the hold uptime is much shorter as expected.  It takes a few minutes to recharge the bank.  So far, this has not been a problem. 
 
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Offline T3sl4co1l

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Re: UPS Supercapacitor Conversion
« Reply #113 on: June 19, 2019, 02:30:23 am »
Sounds like tacking on a few more caps might be a worthwhile investment, but still quite reasonable as-is. :)

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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #114 on: June 20, 2019, 01:34:21 am »
I checked the voltage balance and it doesn't see to have changed much from the original data I took.  They are all still within 500mV.  The parts all continue to run cold.  I really can't tell how they have degraded yet. 

As far as trying to increase the size of the bank.  I may try and find a physically larger UPS now that I have a feel for the system.  Most likely, I would pull the trigger on a name brand for the capacitors.   In the meantime, I plan to put this one back online soon. 

I had a look today and came across where Eaton and Riello both offer smaller units  but they don't seem to offer a 120V single phase system.     If you look at the SentinelProSC, they seem to fall right into the area I am interested in.   The recharge times are much longer than I would have expected but the uptime looks good.  I haven't been able to find any details on them. 

https://www.ecopowersupplies.com/super-capacitor-ups
https://www.riello-ups.com/uploads/file/822/822/DATCAPX0Y18CREN.pdf

Offline tautech

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Re: UPS Supercapacitor Conversion
« Reply #115 on: June 20, 2019, 01:56:10 am »
Is the ProSC a super cap version ?
This all I could find but no 120VAC version:
https://www.riello-ups.com/uploads/file/784/1784/DATSEPA1Y18CREN.pdf


Our ISP put a 1KW version of these in here last week:
https://www.riello-ups.com/products/1-ups/45-sentinel-dual-low-power
We host some of his customers via point to point 5 GHz links and some are far enough away that they're not on the same powerco network and we might lose power and therefore drop their internet connection.

Anyways, it came in an always ON config with it's fan cooling on full blast so we stuck it in ECO mode where the fan is only running when it's actually doing something.  :P
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Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #116 on: June 20, 2019, 11:38:53 am »
Quote
Is the ProSC a super cap version ?
It would seem so based on the couple of links I had found. 

If the non-SC version you found is indeed the same except for the storage, I would try to find something else.   I suspect the larger system you show is more like what I have now.   It sounds like yours defaults with the converter enabled.   The one I am using for this experiment will run the fan even with the converter off but it is running at the lower speed until the charger circuit becomes active.   It works out well as the bank always has some airflow.     

The ones with SCs and Lithium don't seem to be offered in the USA.  I was surprised with people mentioning Riello that they don't offer 120V systems. 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #117 on: December 29, 2019, 06:49:54 pm »
We are coming up on a year and a half of full time operation.    Recently we lost power and I was reminded of this little project.   It's been one of those projects that I seldom think about because it just works.    The first drop was less than a second and of course the UPS rode it out just fine.  However, shortly after it dropped again for several seconds (15ish).  I was only running a light load on the UPS and it was holding up just fine.  The power came back on and I was pleased that everything was still working just fine.   It takes some time to recharge the bank but after a few seconds, it went down for a 3rd time and stayed down for several hours.   

Over the summer, we had lost power several more times and I spoke with one of the crews doing the repairs.  Since then, they have upgraded some of the cables which has improved the reliability.   Of course, downed tress and people running their cars into power poles are a little more difficult problems to solve.   

I'm still very pleased with the system, even with it's cheap capacitor bank. 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #118 on: June 20, 2020, 06:44:44 pm »
Just a few more days and the UPS will have 2 years of 24/7 operation with the cheap caps.  Still set for double conversion.   I plan to take some measurements from it again at the end of the month.   I no longer keep track of the number of line dropouts but it continues to be a problem and the UPS continues to ride out the vast majority of them with ease.   Normally I would be changing batteries by now. 

   
 
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Offline james_s

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Re: UPS Supercapacitor Conversion
« Reply #119 on: June 21, 2020, 01:07:28 am »
Those are some interesting results. I fixed a couple of UPS's recently that just needed new batteries and after looking at datasheets for 9Ah SLA batteries it occurred to me just how hard these things get hammered. In many cases the capacity printed on the batteries is for a 20 *hour* discharge rate and drops by around 10% for a 10 hour discharge with a maximum surge current of somewhere around 8 times the Ah rating. The last UPS I was messing with was a 1500VA/1kW unit with a 24V battery pack so even if we're very optimistic and assume 100% efficiency and no sag below the nominal battery voltage that's still over 40A at full load. At that current those 9Ah batteries are probably going to deliver more like 3Ah and go figure it's not going to take too many cycles to kill them, nevermind overly aggressive charging. Then there is the fact that a lot of times general purpose SLA batteries designed for alarm system and other low power backup applications get sold for UPS duty instead of batteries designed for high discharge rates.

LiFePO4 batteries seem like a perfect fit for UPS duty but even though a retrofit is possible I don't think I'd want to do that, you'd want a UPS designed from the ground up to use lithium cells. Given the developments that have taken place to enable practical electric vehicles I would expect a properly designed LiFe based UPS battery could last 10+ years, easily offsetting the substantially higher cost. By the time you factor in the much lighter weight and resulting lower shipping cost it gets even more competitive.
 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #120 on: October 05, 2020, 01:20:47 am »
Sorry for the delay.  After 2 years 3 months of continuous operation still no house fires to report, the capacitors continue to run cool and the balance still looks good.   

Shown again using the 300W resistive load.  The holdup time has dropped from 17 seconds to a little over 12.   I allowed it to recharge and attempted to run it a second time.  The holdup time remained the same.  The cheap supercaps are starting to degrade but have plenty of life left for this application. 

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« Last Edit: October 05, 2020, 11:18:36 am by joeqsmith »
 
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Offline BradC

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Re: UPS Supercapacitor Conversion
« Reply #121 on: October 05, 2020, 07:31:17 am »
Given the developments that have taken place to enable practical electric vehicles I would expect a properly designed LiFe based UPS battery could last 10+ years, easily offsetting the substantially higher cost. By the time you factor in the much lighter weight and resulting lower shipping cost it gets even more competitive.

Oddly enough if you properly manage and use SLA batteries with an appropriate design life you can get 10+ years out of them also.
 

Offline richard.cs

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Re: UPS Supercapacitor Conversion
« Reply #122 on: October 05, 2020, 09:49:05 am »
It's been almost a year since I started this thread.    Over the past year, the UPS has saved me roughly 20-30 times.   We had 4 or so outages that lasted more than an hour.

Out of interest what part of the US do you live in? This hugely more events than I am used to (southern UK, suburban), I guess you have a lot more overhead distribution but it still seems like a lot.
 

Offline joeqsmithTopic starter

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Re: UPS Supercapacitor Conversion
« Reply #123 on: October 05, 2020, 11:36:09 am »
Longer outages are from overhead lines and trees.  As I have mentioned in this thread, these events are fairly rare.   I have no idea what causes the short duration drops.  These are by far the most common everywhere I have lived.  There are some that appear to be timed but are not long enough to cause a problem. 

It will be interesting to see how these degrade over the next year.  Maybe they degrade more quickly with time.  I wonder too if they are all degrading at the same rate. 

Offline BradC

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Re: UPS Supercapacitor Conversion
« Reply #124 on: October 05, 2020, 11:54:39 am »
I've just re-read the whole thread. Did you ever post details or pics on what you actually did? I can't seem to find any data on the conversion itself, just load / hold-up tests.
 


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