Electrolytic capacitors lifetime and ripple current

Thermal, lifetime, Hybrid polymer capacitors.

[@slazinger]

As a hardware engineer I really enjoy your videos, you seem to have a really deep understanding of electronics. Thank you very much for sharing your knowledge.

[@sambenyaakov]

Thanks for kind comment.

[@Rajat0607]

A much needed topic

[@sambenyaakov]

Thanks

[@misterjorous]

Amazing presentation!!! Cheers.

[@sambenyaakov]

😊🙏

[@bharathkumarrayachoty4582]

Amazing explanation! As usual, simple, yet conceptually sound.

[@sambenyaakov]

Thanks

[@PavolFilek]

Thank very much, I am just building 200 V / 100 A two-phase MPPT, your videos are very very helpful.

[@sambenyaakov]

Excellent!

[@messageobliquespe100]

Bravo! Weeks of research - (KZbin videos - that’s what the kids do these days) Reading /researching manufacturers information - your video has shone a very bright light upon the subject. I can now apply it to why equipment fails & reasons for needing to replace electrolytic’s over time. I think I can save the world armed with this information - ok, not the world but existing electrical equipment & maybe new equipment. Thank you Professor for the time & knowledge shared.

[@sambenyaakov]

Thanks for sharing your thoughts and the worm words. Comments like yours keep me going.

[@tefatronix]

Great presentation... as always.

[@sambenyaakov]

Thanks

[@zaneenaz4962]

This form of analysis is very useful. It takes measurements/multiple data points and makes projections. Having dealt with heat and mass transfer problems have learned there are always more factors to confound the analysis and sometimes even the model. After blowing up a string of capacitors (in cans) this morning due to a misapplied high voltage i'm reminded of the importance of the electrolyte. Thank you for helping me improve my analysis and knowledge.

[@sambenyaakov]

Thanks for sharing and kind words.

[@LightningHelix101]

You always hear electrolytics are the death of electronics. It’s great to see how the magic of lifetimes is tied so closely with their environment (TA) and usage (Ix).

[@sambenyaakov]

Thanks for comment

[@frunsebischkek1050]

Thank you very much for the great explanation. After more than a decade in power electronics I finally have got a nice method to estimate the life time of a electrolytic capacitor. Electrolytic capacitor wears out being used as a filter in a bridge rectifier. Is it reasonable to construct a kind of model of the capacitor to run in the firmware? It would calculate (estimate) the inner temperature measuring the ripple current and case temperature in order to protect the capacitor of wearing out to fast. In some 3phase converters exist such a models to protect the IGBTs of getting to hot and wearing out to rapidly.

[@sambenyaakov]

Tanks for intersting comment. As far as I recall. there is a company that offers such monitoring.

[@pongpitwipasuramonton4092]

Dear sir, what about the freq issue? As I know E-cap does not like low freq ripple as it will get much hotter.

[@sambenyaakov]

Thanks for comment. Good point. I have not touched upon this. Data sheets do provide correction factors for different ripple frequencies.

[@biswajit681]

The formula used in the video it is general formula , formula changes based on capacitor type and manufacturer.we should always refer manufacturers datasheet. Manufacturer also provide the thermal model.

[@sambenyaakov]

Correct. This is an educational video explaining the underneath principles.

[@tamaseduard5145]

👍🙏💖

[@sambenyaakov]

🙏👍😊

[@Stelios.Posantzis]

Very useful. This is great from the engineering perspective but I am wondering whether there is anything similar that can be used for the shelf-life of electrolytics and the life of electrolytics after decommission? For anyone interested in old electronics equipment, assuming how long a piece of equipment has been sitting in storage since last used, the biggest question is: what is the probability a certain electrolytic has gone bad and how did storage conditions affect this probability? I am assuming that simply putting Ta = 25 in the formula won't give an answer here.

[@sambenyaakov]

Yes, as far as I can tell.

[@zaneenaz4962]

​ @Sam Ben-Yaakov Capacitor leakage...looking for residue on circuit board, or components is a first check. wondering if charging and discharging time might also provide more information as to whether lifetime has been reached.

[@zaneenaz4962]

Capacitor leakage...looking for residue on circuit board, or components is a first check.

[@abhi5491]

Great explanation .How to find hotspot temp in Panasonic or other vendor data sheet?

[@sambenyaakov]

Thanks

[@windward2818]

If you look at electrolytic capacitors complete product life cycle, a disappointing recurring theme is the device is not given the proper operational design margin to maximize the overall life of the assembly. In other words, the electrolytic capacitor will fail first. In repair (field returns) we see this phenomenon time and time again, a leaky or failed electrolytic capacitor, why? I believe the engineers, and I have been guilty of this myself, do not provide enough design heat margin (temperature and time) because the actual thermal operating conditions are not fully understood, and the device is, as used in the design, essentially under-rated. The lesson learned with electrolytic capacitors is this: when you think you have a good estimate on component life ---- add additional margin to the design. So you may add an additional 20% to 40% depending on the nature and end use of the design. This is why using a thermal camera as part of the overall design process is very informative. Unfortunately, if the thermal conditions are not extreme, to save cost, you will not see a design revision, which is not ideal. So, having experience in looking at design thermal behavior is very informative early in the design cycle. This usually translates into looking at existing similar product designs and scrutinizing manufacturer evaluation boards. I find that the capacitor is often subjected to internal and PCB hot spots, which directly effect the capacitor's operational life. As part of this hot spot behavior what you find is, the capacitor may need air flow or a specific (planned) heat conduction path and, when the assembly is operating, it cannot reject heat as envisioned by the designer or this heat path is disrupted. For example, it is very common to see many radial lead capacitors bunched together (basically case to case), where obviously the capacitors in the middle of the bunch are not being cooled as effectively as the ones on the periphery. Will the devices in the middle fail first? The operating temperature of the example in the video is helpful for understanding the math, however continuous operation at 100 degrees C for an electronic assembly is a very high operating point.

[@sambenyaakov]

Thanks for sharing your experience/thought

[@biswajit681]

How to calculate lifetime when we have some current profile ?? For example braking application where different time magnitude of current varies based on the force applied to wheels.

[@sambenyaakov]

How about using the manufacturers' themal models you mentioned?

[@biswajit681]

@@sambenyaakov yes sir I have some thermal model but I couldn't solved it till now ...I am not getting how should I use manufacturers thermal model

[@eurosetvk]

Did you just see the table you presented? Which conclusions can we do? If you replace one capacitor to two capacitors, you will get more lifetime cause much more summary current limits and doing your ESR as parallel resistors actually. Isnt it? The second conclusion i can do (summary) is "more dimmensions - more lifetime and less ESR". isnt it?

[@sambenyaakov]

Thanks for input.

[@byronwatkins2565]

Common log tables are base 10. Natural log tables are base e. No published log tables are base 2; though log tables are less relevant in a binary world...

[@sambenyaakov]

Yes, but with calculators at your fingertips, who need table or abacus😊?

[@byronwatkins2565]

@@sambenyaakov As I said; but that is the reason they use base 10.