Doubts electrolytic capacitor

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james23051987

Joined Aug 13, 2020
6
electrolytic capacitor of my devices needs to be energized 1x a month for at least 30 minutes
to avoid problems with drying and depolarization? I have a friend who advised me to use my old or new electronics 1x a month otherwise it would cause problems for the electrolytic capacitors

is this information true?

 

jpanhalt

Joined Jan 18, 2008
10,246
As Snoops might say, "partially true."

Yes, electrolytic do dry out and can loose some of their initial polarization.

What is not true are the frequency that they need to be used to reform them (keep the initial polarization) and whether use per se prevents them for drying out or may actually accelerate it. I have used electrolytics that had been unused for 20 years with no problems. Here is one recommendation from Google that seems conservative to me:
ESR and leakage current increase while capacitance decreases. Nevertheless, the changes are small if these capacitors are stored at room temperature. Today's aluminum electrolytic capacitors have longer shelf life, usually around 2 years, as compared to their predecessors.Mar 1, 2018
Several years might be a compromise.

This is from Epcos on reforming:
3.7.5 Reforming
To IEC 60384-4, aluminum electrolytic capacitors are to be subjected to a reforming process before
acceptance testing. The purpose of this preconditioning is to ensure that the same initial conditions
are maintained when comparing and assessing different products.
For this purpose, the rated voltage is applied to the capacitors via a series resistance of approximately
100 W for VR £100 V DC, or 1000 W for VR >100 V DC, for a period of one hour.
Subsequently, the capacitors are stored under no-voltage conditions for 12 to 48 hours at a temperature
between 15 and 35 °C. The leakage current must then be measured, at the latest after
48 hours.
If the capacitors meet the leakage current requirements without preconditioning, this procedure
can be omitted.
As for drying out, that is a function of type (solid tantalums do not dryout), and probably environment and temperature. I cannot see how warming them though use would help prevent that.
 

Papabravo

Joined Feb 24, 2006
14,420
Sort of. They may dry out eventually, but there are numerous factors involved. I am unsure if turning a device on once a month will have any affect on capacitor ageing. A ten year old capacitor is...well a ten year old capacitor.
 

Thread Starter

james23051987

Joined Aug 13, 2020
6
I'm still in doubt if I have to use my electronic devices once a month to preserve the capacitors electrolytic if you don't use the electrolytic capacitors for a long time they will prematurely lose useful life?


My friend said that if I use the devices once a month the useful life of the electrolytic capacitors is increased
 

Thread Starter

james23051987

Joined Aug 13, 2020
6
I don't know he is just an electronics technician but he didn't say where he saw this information so I asked here and you are experts in this subject
 

MrChips

Joined Oct 2, 2009
21,877
Partially true, partially urban myth.

There are too many variables involved with electronic gadgets. My recommendation would be to do as you please and don't lose sleep over it.

The one thing I have learned from personal experience of over 50 years in the technical field, electronics last longer if you never turn the power off. What shortens the life of electronic components is frequent ON-OFF cycling.
 

SamR

Joined Mar 19, 2019
2,590
The only case for once a month that I can think of is when a capacitor is used to keep the voltage on a volatile memory instead of using a battery. They have been arguing the merits of that one for quite a while now.
 

dendad

Joined Feb 20, 2016
3,602
I too have stocks of electrolytic caps that are 20 years old, and they are still ok.
They may have lost some off their capacitance, but I would have to measure them to find out. That said, I have no problem using them in new products.
Even under use, they do dry out. This is particularly so for caps in high current applications, like switch mode supplies. The most common fault in these supplies is dried out and or leaky electrolytic caps.
One of the industrial controllers I made come back for repair after 15 years and it is always the caps in the power supply that have died.
Most "dead" video monitors have this problem. And when the caps do dry out, extra voltage spikes produces becuse of the lack of filtering can pop other things too.
So my take on this is, once a month is a bit of overkill, but by all means do it anyway.
 

dl324

Joined Mar 30, 2015
11,543
is this information true?
Without more qualification and references, I say no.

I have literally hundreds of pieces of equipment and I only power them when I'm going to use them. Most sit idle for years at a time. I've never had problems with electrolytic caps drying out.

I have a DVR that was used just about every day for about 10 years and had 5 electrolytic caps go bad. They may not have all failed at the same time, but when it wouldn't power on, I replaced all 5 because they had bulging tops.
 

MisterBill2

Joined Jan 23, 2018
7,033
I don't know he is just an electronics technician but he didn't say where he saw this information so I asked here and you are experts in this subject
Here you will find not only "experts", but also those who are not experts, and some whose information is incorrect. And even a few who make errors occasionally.
Some brands of electrolytic capacitors have a shorter life than others.

AND, not everything that you find on the internet is correct.
 

Thread Starter

james23051987

Joined Aug 13, 2020
6
What is the correct information from the experts? electrolytic capacitors stored for a long time depolarize and short circuit? What is the maximum time allowed to energize the electrolytic capacitors and prevent them from having these problems?
 

jpanhalt

Joined Jan 18, 2008
10,246
Shelf lives are not precise numbers. Too many variables, like details of construction, electrolytes, capacitance, voltage rating, temperature, etc.

The guidelines from manufacturers are all 2 years or more. That means that your friend's "1 month" recommendation is foolishness.

Here is the recommendation from Panasonic: https://docs.rs-online.com/3abe/0900766b800bd1a1.pdf


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Papabravo

Joined Feb 24, 2006
14,420
What is the correct information from the experts? electrolytic capacitors stored for a long time depolarize and short circuit? What is the maximum time allowed to energize the electrolytic capacitors and prevent them from having these problems?
Sorry to disappoint you but there are no universal answers. There are no reliable statements you can make on these topic unless they come from an engineer at a capacitor manufacturer with actual product life cycle data. As users of the product, the best we can offer is anecdotal information based on our own experiences.
 

Thread Starter

james23051987

Joined Aug 13, 2020
6
Does any electrolytic capacitor manufacturer say if I should use the electronic device once a month for 30 minutes to preserve the electrolytic capacitors and prevent them from depolarizing and short circuiting?

I have a lot of new and old electronics from 1990
 

dl324

Joined Mar 30, 2015
11,543
electrolytic capacitors stored for a long time depolarize and short circuit?
They don't depolarize or develop shorts.

The one month time you were given by friend is suspect and I'll say he's wrong. I don't think there are any capacitors that have a shelf life as low as 1 month.

How capacitors age depends on a number of factors (e.g. time, temperature, and the presence of halogen gases). An "aged" capacitor could exhibit reduced capacitance, increased leakage, and/or increased ESR that you may not be able to measure because manufacturers are generally conservative in their specifications. As long as they're within manufacturer specifications, you have nothing to worry about.

When "old" capacitors are powered, they'll reform while in use. The caveat is that if parameters have changed enough, the capacitor and/or the circuit may not survive reforming under load.
 

ericgibbs

Joined Jan 29, 2010
10,818
hi james,
If you ever consider testing very old, high voltage, high capacitance, capacitors, say 470uF upwards and >100Vdc working, do so using a low start voltage and heavy duty series current limiting resistor.

I have seen old electrolytic caps violently explode and vent their internal foil.

This is not Wiki speak, its practical experience,
E
 

Thread Starter

james23051987

Joined Aug 13, 2020
6
electrolytic capacitor depolarize and have a short circuit if I don't use it 1x per month for 30 minutes is this wrong information? what is the maximum amount of time allowed q i should use the device to preserve the electrolytic capacitors from this problem?
 
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