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PSU Electrolytic Capacitor Aging

Last response: in Components
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May 7, 2011 8:48:06 PM


Capacitor aging, where a PSU produces less total output due to heavy or extended use (normal wear) is a factor in all power supplies. It is recommended that one purchase a PSU that provides 30% more power than is needed to compensate. Doesn’t a PSU that is “capacitor aged” lose efficiency?

If the absolute best PSU efficiency available is 90%, in a perfect world, wouldn’t you want to replace your PSU once it has fallen below this efficiency margin so as not to waste electricity any more than necessary? it's suggested to purchase high efficiency PSUs, and at the same time, its encouraged to buy more power than is needed so that once that PSU starts being less efficient we still have enough power left to run our PC.

While this makes perfect sense to ensure your PC doesn’t stop functioning due to a lack of power, shouldn’t we be making it more clear that PSUs drop their stated efficiency after a year of regular use, and instead of buying so much more than is needed, shouldn’t we spend less money to buy less power to begin with, but change PSUs more often?

High quality brand name PSUs are expensive, but a higher wattage PSU is stilll more expensive than a lower wattage one - brand name or not. Isn’t it cheaper to buy something much closer to the expected full-load level, then replace it a year later? If it isn’t cheaper now, won’t it be cheaper when manufacturers realize that mid to high-end PSU users buy new PSUs every year, meaning more sales volume met with lowered prices?

Aren’t quality PSUs (Antec, PC P&C, Seasonic, Thermaltake) warrantied to run at their stated wattage for 3 years? No one wants to bet their hardware on that warranty, but, shouldn’t we be holding them to this?

If you knew you wouldn't add new components to your current build later on, would you still buy a PSU with 30% extra power now, or just what you needed, then buy a new one next year, assuming the price was right?



May 8, 2011 6:35:44 AM

opinion polling?

Personally I like to add the extra 30% because I leave some of my pcs on 24/7. There are people on here that say its all bunk and they may be right but Ive had a cap blow on a system and shoot brown goo all over the inside of my pc because I was running close to its max capacity for over a year but was shutting it off when I finished playing a game on it.

Buying less power only makes sense if you a) know you'll not be using the system that often. b) know you wont upgrade. and c) like to spend money every year upgrading and rewiring your system. Spending the money on more power than you need allows you to skip all those issues and use the thing like a toaster or game console... use it when you want it and expect it to work ... shut it off when youre done and walk away.
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May 8, 2011 3:33:06 PM


Shinobi, I am kinda opinion polling. The thing is, I'm having a very difficult time coming up with a mathematical way to gauge how much power I really need because of all this misleading information. i agree with you about overspeccing power for peace of mind, but, I like wiring my system, it's a guy thing.

jsc said:


I would like to see a site like hardwaresecrets test a 5 year old Corsair 750TX.


This is something I would really like to see myself, I was going to suggest it, but figured I already had too many TL:D Rs. I don't even think it needs to be that old, 2-3 years of full load and near 24-7 operation, one should be tested to see how well it performs compared to a new one.

I've never seen PSUs warrantied for 3-5 years come with a caution that running them at full load voids the warranty. Wouldn't manuf. be begging for lawsuits if the products they warrantied for 5 years to run at 500W only produced 450W after 2 years, and died on someone because his gear still required 500W?

So why are we still recommending that people buy an extra 30% power, plus another extra 100-200Watts?

I want to buy a "Seasonic S1211 520" to run a 2500k@4400 & HD6850, and I may as well just stop thinking and buy a 750W PSU because instead of statistical and logical recommendations, all we have are people saying "this is what I feel comfortable with"




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a c 243 ) Power supply
May 8, 2011 3:56:17 PM

Capacitor Aging
http://www.rubycon.co.jp/en/products/alumi/pdf/Life.pdf

The calculations from the above, done when the planets are aligned, the stars swirling and a baby bunny has been sacrificed, will give you an estimate, that doesn't take the difference in quality between manufacturers into account. And would only be valid if the variables were constant.

How would anyone know if they were running a capacitor close to max capacity?
And if they knew, would they continue to do so ?
They wouldn't go out driving and keep the tach in thier car redlined, or would they ?

Unless you're looking at buying a cheapo psu, where adding the cap. aging into the calculation might buy you a little more time, it ain't neccessary.
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a b ) Power supply
May 8, 2011 5:55:05 PM

I'd love to see an older, good, and used PSU tested as well.
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a b ) Power supply
May 8, 2011 6:26:34 PM

Primary effect of large value electrolyic capacitor ageing is an increase in leakage current - the end result is higher ripple frequence on the output and poorer regulation.

With quality parts a PSU can provide many years service beyoun the warrenty period. Have 4 PSUs that are approximately 20 years old. Thes PSUs are calibrated every year and the ripple is measured and they would have been replaced if any out of spec conditions were noted. (PS these are not cheap PSU, the output is 28 VDC and is fully adjustable down to 5 VDC and the current overload is adjustable).

A 2nd point; older electrolyticstend to dry out if unused for extended period of time - Reason a lot of older psu when "POP" when brought out of storage.

I also use 20 % above max load as a minimum PSU rating. Also if looking at eff, you also need to look at idle power, should be above 20% of PSU rating. My Ideal PSU would be 20 % at idle and between 50 -> 70 % at max load - also look to future, like adding a 2nd gpu or a higher power GPU.
Example MY system about 120 W Idle and 320 Watts max. PSU 120/.2 = 600 Watts, 320 /.7 = 460 W. So a "good 500-> 600 Watt would be great. Using a 600 W.

For Power, I generally google a review of the GPU and Look at idle/load power for the System (Normally a High end I7 that is OCed) and go from there.
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May 8, 2011 9:06:11 PM

delluser1 said:

How would anyone know if they were running a capacitor close to max capacity?
And if they knew, would they continue to do so ?
They wouldn't go out driving and keep the tach in thier car redlined, or would they ?

Unless you're looking at buying a cheapo psu, where adding the cap. aging into the calculation might buy you a little more time, it ain't neccessary.


It's not that I want to buy a cheap PSU, last I checked Seasonic makes quality PSUs. It's that bigger is too often passed off as better, instead of really solid recommendations with solid reasoning to back that up.

Thanks for the links and comments guys. I hope to see a review of this nature in the future Toms.
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May 9, 2011 12:12:10 AM

delluser1 said:

How would anyone know if they were running a capacitor close to max capacity?
And if they knew, would they continue to do so ?


I assume I was running near max capacity because I used the pc about 2 or 3 times a week and the psu was about 2 or 3 years old (enermax so a good brand) and about 30 minutes into a game it popped and died. Since I hadnt changed anything except my gpu in that rig for about a year I have to assume that's what happened. According to the psu calculator I should have only been drawing about 450w for a 550w psu but it appears that was too much. Hence why I continued to run it that way... it SHOULDNT have been a problem. but it was.
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a c 243 ) Power supply
May 9, 2011 1:18:09 AM

shin0bi272 said:
I assume I was running near max capacity because I used the pc about 2 or 3 times a week and the psu was about 2 or 3 years old (enermax so a good brand) and about 30 minutes into a game it popped and died. Since I hadnt changed anything except my gpu in that rig for about a year I have to assume that's what happened. According to the psu calculator I should have only been drawing about 450w for a 550w psu but it appears that was too much. Hence why I continued to run it that way... it SHOULDNT have been a problem. but it was.

The Extreme psu calculator won't tell you power consumption, it will give what it considers to be a minimum, and reccomended psu wattage.

This one will give you a general idea of power consumption and thier reccomendation;
http://www.raptoxx.com/calculator.php

A watt meter ( along with a little math ) can help to give an idea
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

A fancy psu can give you an idea
http://www.jonnyguru.com/modules.php?name=NDReviews&op=...

You could use a clamp meter and some math.

Using the pc 2 or 3 times a week, and it being a 2 or 3 year old psu and popping, doesn't mean you were running near max.
And, running a psu near it's max rating and a capacitor near it's max rating are 2 different things.

Yes, Enermax is a good brand, doesn't really matter even the best can fail.

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