As we all know, a good LED could last very long up to 50,000 hours with with a good heat sink. But how is the LED driver electronics life? For common LED drivers there is at least one component is very weak. It’s the electrolytic capacitor.
High Bay LED Lighting Driver Heat Dissipation Temperature Test Report article gives some use useful information related to electrolytic capacitor life.
Typical temperatures for the how electrolytic caps are 85°C and 105°C. Usually the life time is 2000 or 3000 hrs at one of the above temperatures. This is how electrolytic caps are specified. But the cap’s life doubles for every 10°C below that temperature. So if you go 40°C below the specified temperature, you gain a factor of 2^4 = 16. 16× 3000 hours = 48,000 hours.
If your LED driver has caps at temperature 80 °C, the LED driver only can last about 2 years or less. After that time you can expect poor performance (lowered capacitance, increased ESR) or even capacitor exploding.
34 Comments
Tomi Engdahl says:
Trading off lifetime vs. cost in LED light capacitor selection
http://www.edn.com/blog/PowerSource/41629-Trading_off_lifetime_vs_cost_in_LED_light_capacitor_selection.php?cid=EDNToday_20120216
IC family specifically says that the driver can be made with no electrolytic capacitors – in other words, with ceramics. But as Andy Smith points out, the company (Samsung) has a bill of materials budget that it has to meet, and quite likely the Samsung designers didn’t have the luxury of specifying ceramic capacitors for this product.
However, electrolytic capacitors, when properly derated, can provide reliable performance.
It isn’t management demanding low prices, it’s the customers. No one is going to sell LED dulbs with 2$ capacitors, insideas Ed suggested, since the final price to the consumer is unacceptable.
The actual cost at the checkout includes tax, retail markup, internal distribution, import, export, transport, packaging, advertising &NRE, and factory markup, so the total BOM cost is going to be about 10% of the sticker price.
Fallon Brezenski says:
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Tomi Engdahl says:
Consider Ceramic Caps for LED Lighting Systems
http://www.digikey.com/us/en/techzone/lighting/resources/articles/consider-ceramic-caps-for-led-lighting.html
Designing an LED lighting system is becoming a more complex task as designs incorporate electronics for LED dimming, color, wireless control, and system “intelligence.” While engineers typically pay more attention to their choice of power devices, drivers and thermal management circuitry, they should not lose sight of the need to select the right capacitor for the job.
Despite their higher temperature stability and smaller size when compared to such capacitor types as film and aluminum electrolytic, too often designers have passed on the use of ceramic capacitors for LED lighting, largely because of their piezoelectric noise, which admittedly has been a cause for concern.
This article will look at advances in ceramic capacitor technologies that provide reduced noise and DC smoothing in LED lighting circuits. Examples provided will include Murata’s GR3 and RDE series and AVX’s QM series.
Ceramic capacitor makers agree that noise is one of the biggest issues for LED lighting designs, particularly as LED dimming becomes more popular. Ceramic capacitors operating with a pulse width modulation (PWM) dimmer circuit can cause acoustic noise and light flickering due to piezoelectric effects within the ceramic material. Another potential obstacle is the capacitive DC bias of the ceramic capacitors, which results in a lower capacitance value.
That being said, it does not take a Ph.D. from MIT to conclude that ceramic capacitors exhibiting lower noise and a higher capacitance value under DC bias will prove attractive for LED lighting designs. Ceramic capacitor suppliers know this, too, and they have taken different roads to resolve these issues, either by using new dielectric materials or by designing new internal electrode structures.
Since LEDs are robust devices, just about any circuit used with them will negatively impact reliability, so the goal is to select circuits that will have the least negative impact.
Designers should always evaluate all capacitor technologies for LED lighting applications, whether they are going to be used in rectification circuitry, output filtering or noise suppression. Performance tradeoffs will be based on each application’s requirements.
Looking at ceramic capacitors in particular, designers should not automatically discount them for use in PWM dimming control circuitry because of their piezoelectric noise. Advances continue to be made in capacitor technologies, opening the door to their use in this and other new applications.
Shiela Bagan says:
Thanks a bunch for posting!
content says:
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Tomi Engdahl says:
Ensure long lifetimes from electrolytic capacitors: A case study in LED light bulbs
http://www.edn.com/design/analog/4411475/Ensure-long-lifetimes-from-electrolytic-capacitors–A-case-study-in-LED-light-bulbs
Hot LEDs and short-lived electrolytic capacitors
I personally measured component temperatures as high as +130°C in light bulbs purchased at local retail stores. Now admittedly, these were early LED bulb designs. Manufacturers now understand that, even though these LED bulbs consume substantially lower power than those they would replace, they still must have good thermal engineering. This is the only way to get the lifetime of the electronics to match the lifetime of the LEDs themselves.
I found it disturbing that many of these hot designs contained electrolytic capacitors which are notorious for a short lifetime at elevated temperatures. I expected that the lifetimes of these capacitors would severely compromise the lifetime of the products, and not allow them to reach the 30,000 to 50,000 hour capability of the LEDs themselves. With common electrolytics rated at 2,000 to 5,000 hours at +85°C, I vowed not to use an electrolytic in any LED bulb designs.
In talking to LED bulb manufacturers at that time I found that many did not understand the limitations of electrolytic capacitors.
It is important to understand both the “endurance” spec of electrolytic capacitors and how temperature affects it.
Conversely, lifetime decreases by a factor of 2 for every +10°C increase in temperature. Therefore, at +100°C, the endurance of the 2,000 hour, +105°C-rated capacitor mentioned above would be 21/2 x 2000, or about 2800 hours. Even if you assume that, on average, the capacitor operates at +95°C, its lifetime only increases to 4000 hours. This is hardly the 30,000 to 50,000 hours desired for LED light bulbs.
This is a good example of the importance of fully understanding the details of component specifications.
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Tomi Engdahl says:
The case of the flat panel TV scream
http://www.eetimes.com/author.asp?section_id=30&doc_id=1284996
Sometime during the day the TV began to “scream”; a loud high-frequency buzzing coming from the speakers. They called the local cable company to come out and fix it (thinking it had something to do with the cable box). When the cable tech couldn’t fix it they called in a TV place to fix it. That person told them the panel couldn’t be fixed. Given that it is a waiting room they said replace it and put the old one aside to go in the trash.
My wife (of 24 years) immediately thought “Mike can fix it” and asked if she could take it home. Her boss said “sure, but they said it can’t be fixed.”
As soon as my wife told me the issue I had a pretty good idea what was wrong, but I had to open it up to be sure.
I’ll give you the symptoms and if you’ve been around any piece of electronic equipment in the last 10 years you’ll most likely get it right away.
The panel came on, the CCFLs lit and all controls worked. As it came on you could hear the “squealing” start and ramp up very fast to a high pitch.
Look to the cap
Having worked on SMPS and seen similar problems before I knew one of the power supplies had to be the culprit, and more to the point a filter cap had to be the source of the problem.
A quick look around the boards and I found the culprit; two of the electrolytics on one of the supplies were bulging.
I pulled the supply out and removed the caps.
I replaced them
I turned the panel on and presto, no noise. So, a panel that had been deemed “unrepairable” was now mine for the cost of about 40 minutes of my time and a couple of replaced caps.
Tomi Engdahl says:
Safety warning: Arduino GSM shield may cause fires
http://hackaday.com/2013/09/24/safety-warning-arduino-gsm-shield-may-cause-fires/
Be careful with those Arduino GSM cards. As [James] reports, they may turn into fire starters. One person has reported a small explosion and fire already on the Arduino forums
[James] states the problem is a tantalum capacitor used to decouple the GSM radio power supply from the main Arduino supply.
Tantalum capacitors are great for their low ESR properties. However, they have a well known downside of getting very hot, or even exploding when stressed.
It’s not the Tantalum Anode that is burning. The Manganese Dioxide used as a cathode in some Tantalum capacitors is the culprit.
It comes down to voltage rating (or more aptly, derating). The Arduino GSM shield runs at 5 volts. The designers chose a 6.3V rated capacitor. While this close of a tolerance may be good enough for some types of capacitor, it is a no-go for a Tantalum cap with Manganese Dioxide.
The dielectric material in these capacitors is so thin that the stress of a reflow oven cycle causes cracks. The cracks pass leakage current, and this sets the Manganese Dioxide on the path to destruction.
What’s the solution? [James] suggests several options:
1. Switch to a 10 volt part
2. Switch to a safer Tantalum Polymer capacitor.
Tomi Engdahl says:
What the cap?
http://wtfmoogle.com/?p=3585
when I start hearing this pop pop pop pop sound…
No power necessary…. these spare caps blew by themselves…
Yay for Truth branded caps!
aqualusso steam shower says:
Adore this blogging site, amazing work
Tomi Engdahl says:
Aluminum capacitor slideshow: Handling heat issues
http://www.edn.com/design/analog/4439149/Aluminum-capacitor-slideshow–Handling-heat-issues?_mc=NL_EDN_EDT_EDN_analog_20150409&cid=NL_EDN_EDT_EDN_analog_20150409&elq=fb4444feb5e44abd9f6c75715c15c8e5&elqCampaignId=22468&elqaid=25263&elqat=1&elqTrackId=7f4dfca5c59e4786855a82eca4c0814a
The lifetime of an aluminum electrolytic capacitor will be shortened as its temperature increases. For every 10 degrees C decrease in temperature at the hottest spot of the capacitor, its lifetime is essentially doubled, so the lifetime varies exponentially with heat.
Let’s delve much more deeply into this issue with Vishay’s educational technical presentation
Your system reliability will strongly depend on keeping the heat down in capacitors.
Tomi Engdahl says:
Aluminum capacitor slideshow: Handling heat issues
http://www.edn.com/design/analog/4439149/Aluminum-capacitor-slideshow–Handling-heat-issues?_mc=NL_EDN_EDT_EDN_weekly_20150416&cid=NL_EDN_EDT_EDN_weekly_20150416&elq=baa986391459406f89da378a9e63d81e&elqCampaignId=22580&elqaid=25391&elqat=1&elqTrackId=6b0bcb35649d43b4851e4f3d3bb40e58
The following presentation is an excellent technical tutorial given by Vishay Product Marketing engineer, Theo van de Steeg on handling heat issues when working especially with aluminum capacitors.
The lifetime of an aluminum electrolytic capacitor will be shortened as its temperature increases. For every 10 degrees C decrease in temperature at the hottest spot of the capacitor, its lifetime is essentially doubled, so the lifetime varies exponentially with heat.
Tomi Engdahl says:
Why we don’t replace all vintage electrolytic capacitors
https://www.youtube.com/watch?v=GMNQDoFpYQY
Judging from the comments on my last video, there is much misconception about if and when to replace vintage electrolytic filtering capacitors. This video explain why, contrary to widespread internet lore, we don’t often feel compelled to replace our vintage electrolytic caps. Caveat emptor: although we are engineers in real life, we are dabbling hobbyists when it comes to component reliability. The physics and statistics of reliability is very heady stuff better left to specialized scientists and requires very complicated investigations.
Tomi Engdahl says:
Bad Electrolytic Capacitor Teardown
https://www.youtube.com/watch?v=tKphKWAkeSU
A classic story: a computer monitor which has ceased to work due to a failure of a 4 cent capacitor. In this video the capacitor is torn down to inspect its’ construction and to sort down why it failed.
Planned obsolescence or simply bad engineering?
Tomi Engdahl says:
EEVblog #33 1of2 – Capacitor Tutorial (Electrolytic, Tantalum, & Plastic Film)
https://www.youtube.com/watch?v=xlvqUts9H9c
Dave attempts to give the low-down on different capacitor types in under 10 minutes, can he do it? (Hint – Dave likes to waffle…)
Tomi Engdahl says:
#76 Tutorial: Why do electrolytic capacitors fail so often
https://www.youtube.com/watch?v=OH6U2SKQaOw
In this episode we try to understand an electrolytic capacitor a little bit better. We do some experiments and some theories on how it works.
Tomi Engdahl says:
Ask Hackaday: Experiences With Capacitor Failure
https://hackaday.com/2019/04/12/ask-hackaday-experiences-with-capacitor-failure/
Tomi Engdahl says:
https://hackaday.com/2020/07/01/unrolling-the-mystery-inside-an-aluminum-electrolytic-capacitor/
Tomi Engdahl says:
Electrolytic capacitors determine the lifetime of a power supply
Manufacturers’ lifetime ratings are important, but so is the specific application.
https://www.xppower.com/resources/blog/electrolytic-capacitor-lifetime-in-power-supplies
Overview:
The electrolytic capacitors in AC-DC power supplies have a finite lifetime.
Manufacturers provide an assessment of their likely durability to help buyers choose the most appropriate solution.
Other variables in different applications will also affect lifetime.
Our Technical Director, Gary Bocock summarises the manufacturer calculations and recommends an extra in-application check.
Electrolytic capacitors are an essential component of AC-DC power supplies. They provide high Capacitance x Voltage (CV) and low Equivalent Series Resistance (ESR) in low-volume packages. There’s no alternative part that can do the job cost-effectively.
Determine the service life of the power supply
The service life of these electrolytic capacitors is an increasingly key design parameter in power supplies. Power density demands are increasing, and electrolytic capacitors are the only component in the power supply that wears out. So, the type of electrolytic capacitor used in the design determines the service life of the power supply. It also dictates the service life or service interval of the end application in maintained equipment.
The topology and applied ripple current, design layout, capacitor design lifetime, capacitor temperature rating and local heating effect vary from one product to another. They may also change under low- and high-line input conditions.
External heating effects can outweigh internal heating effects, especially in today’s increasingly compact designs. Actual service life is also dependent on the temperature rises that may take place when the power supply is installed in the application. The mission profile of the end equipment is another factor, defining average operating temperature over the equipment lifetime and usage hours per day.
Electrolytic capacitor designers take into account all these factors when defining the lifetime of their products. Let’s take a look at the calculations they work with.
Tomi Engdahl says:
Replacing capacitors in vintage equipment
https://www.youtube.com/watch?v=a01egKzQCa8
After 20 years of faithful service, this viewer wants to know if he should replace the capacitors in his equipment and what to look for in new ones. Paul gives us some insights into when it’s a good time to switch and what to replace them with.
Tomi Engdahl says:
Would better components reduce disasters?
Various gadgets are simply tossed out after a few years, either because they are obsolete due to a short lifecycle or they just fail.
There are mechanical and electronics failures. In very many cases the root cause for failure of long used mains powered device is that the electrolytic capacitors used for filtering of the power supply have failed.
Capacitor-replacement repairs is practical for the average consumer and recapping is often time consuming for those who know how to do repairs.
More:
https://www.edn.com/would-better-electrolytic-capacitors-reduce-e-waste/
Tomi Engdahl says:
1000uF Capacitor explodes (vapour white-out)
https://www.youtube.com/watch?v=N0UUyzdzxkQ
Applying reverse polarity at 5A to a 1000uF capacitor.
The white-out is the fog of electrolyte produced when the capacitor explodes.
1000uF capacitor fails catastrophically
https://www.youtube.com/watch?v=2D7VkqKAk-Q
Better lighting for maximum boom-vision.
This is a 1000uF capacitor blowing its cover off completely.
Tomi Engdahl says:
470uF capacitor explodes out schmoo
https://www.youtube.com/watch?v=N5LrWeEG7oc
Better lighting for maximum boom-vision. Taking YouTube “shorts” to a whole new level.
This is a 470uF capacitor venting forcefully from its safety pressure release.
Tomi Engdahl says:
https://forum.digikey.com/t/aluminum-capacitors/12827
Tomi Engdahl says:
https://en.wikipedia.org/wiki/Capacitor_plague
Tomi Engdahl says:
Does a RECAP of old electrolytic capacitors in pro audio gear really makes a difference?
https://m.youtube.com/watch?v=XIbcao9LnPs
Tomi Engdahl says:
Six Shooter Swaps Powder For Popped Capacitors
https://hackaday.com/2022/08/29/six-shooter-swaps-powder-for-popped-capacitors/
Modern firearms might seem far removed from the revolvers of the Old West, but conceptually, they still operate on the same principle: exploding gunpowder. But as anyone who has put too much voltage through an electrolytic capacitor knows, gunpowder isn’t the only thing that explodes. (Yes, it isn’t technically an explosion.)
[Jay Bowles] wondered if it would be possible to construct an electrically-fired weapon that used used a standard capacitor in place of the primer and powder of a traditional cartridge. While it would naturally have only the fraction of the muzzle velocity or energy of even the smallest caliber firearm, it would be an interesting look at an alternate approach to what has been considered a largely solved problem since the mid-1800s.
I Built An Electric Capacitor Revolver!
https://www.youtube.com/watch?v=4Fy9bZEufx0
Tomi Engdahl says:
Electrolytic Capacitors: Comprehensive Overview, Teardown, and Experiments
https://www.youtube.com/watch?v=MAP-VA1m-A4
Through experiments, I compared different types of electrolytic capacitors such as solid and hybrid.
0:00 Brand Name Changes to Chemi-Con!
0:33 Which Products Use Eleltrolytic Capacitors?
2:26Difference Between 3 Types of Aluminum Electrolytic Capacitors
3:04Type 1: “Commonly Used” Aluminum Electrolytic Capacitor
4:34 Structure and Equivalent Circuit of an Aluminum Electrolytic Capacitor
5:40Type 2: “Low ESR” Conductive Polymer Aluminum Solid Electrolytic Capacitor
6:45 Type 3: “Get the Best of Both Worlds” Conductive Polymer Hybrid Aluminum Electrolytic Capacitor
7:16 ESR (Equivalent Series Resistance) of Electrolytic Capacitors
8:49 Lifetime of Electrolytic Capacitors
10:09 Same Capacitance, Different Ripple Voltages
12:19 Reverse Polarity (*Do Not Try This Yourself*)
13:26 Operating Temperatures of Electrolytic Capacitors
Tomi Engdahl says:
Six Common Mistakes Made When Recapping Vintage Electronics
https://www.youtube.com/watch?v=BeDKwi-GJRI
Short little video on common mistakes seen when recapping (replacing capacitors) vintage electronics. This would include vintage stereos, radios, equipment, CBs, ham radio receivers & transmitters, calculators, computers, you name it.
Hopefully this will provide you some tips and hints to use when you go to recap your piece of vintage gear.
Topics include:
- Mistaking Factory Glue for Leaking Capacitors
- Factory Boards and Manuals Marked Wrong
- Capacitors Installed Incorrectly
- Using Larger Capacitors Than Specified
- Buying Electrolytic Capacitors off Ebay
- Replacing Everything at Once
Tomi Engdahl says:
Recapping: It’s the New Bloodletting
https://www.youtube.com/watch?v=VKVejMuCajk
Replacing capacitors is no substitute for repair. It is not a panacea or cure all. Reasons to recap are discussed, as well as horror stories of recaps gone bad.
Replacing Electrolytic Capacitors
https://www.youtube.com/watch?v=iPCAYOz80Xw
This video illustrates a method of “recapping”–removing and replacing electrolytic capacitors on a circuit board.
Failing capacitors can cause a computer or electronic device to malfunction.
Tomi Engdahl says:
Ever wonder what’s inside an electrolytic capacitor? Many of us don’t, having had at least a partial glimpse inside after failure of the cap due to old age or crossed polarity. The rest of us will have to rely on this behind-the-scenes demo to find out what’s inside those little aluminum cans. Perhaps unsurprisingly, it’s more aluminum, at least for the electrolytics rolled himself at the Nippon Chemi-Con R&D labs….
LEARNING ABOUT CAPACITORS BY ROLLING YOUR OWN ELECTROLYTICS
https://hackaday.com/2023/10/24/learning-about-capacitors-by-rolling-your-own-electrolytics/?fbclid=IwAR1QsjftV1TuFMXxX_CeaNuj3D5eb_0Vfzoq09romjcYS5XaPYQteCBgrZU
Ever wonder what’s inside an electrolytic capacitor? Many of us don’t, having had at least a partial glimpse inside after failure of the cap due to old age or crossed polarity. The rest of us will have to rely on this behind-the-scenes demo to find out what’s inside those little aluminum cans.
Perhaps unsurprisingly, it’s more aluminum, at least for the electrolytics [Denki Otaku] rolled himself at the Nippon Chemi-Con R&D labs. Interestingly, both the anode and cathode start as identical strips of aluminum foil preprocessed with proprietary solutions to remove any oils and existing oxide layers.
I made my own Capacitor at CHEMI-CON!
https://m.youtube.com/watch?v=UQu__pO9bZ0
Tomi Engdahl says:
Recycling
https://youtu.be/D4sIBGyqN6g?si=PLLTbp_UUiCwP1tB