I had problems replacing caps for power supplies, they last a couple of years and fail again. I was told Panasonic last a long long time, but there are fakes out there too, any suggestions? thanks

 

Buy them from a trusted source, or salvage them from scrapped name-brand power supplies. Badcaps.net will have a list of good brands.

 

The "Brand" is not necessarily the issue here.
All Capacitors have Specifications,
and most of the time , ( or at least some of the time ), You get what You pay for.

Heavy-Duty Capacitors,
with excellent specifications tailored your particular application,
will never be the "cheap ones".

Capacitors generally don't like Heat.
The cooler You keep them, the longer they will last.
They also don't like Over-Voltage-Spikes.

How much Current are You expecting out of your Power-Supplies ?
Did You know that Capacitors have a Maximum-Current-Rating ?

Stick with the major Electronics-Distributors, and
pay attention to, and understand the Spec-Sheets,
and You won't be disappointed.
.
.
.

 

Seconding the "Trusted source"
One issue found in failed Chinese sourced devices such as AC motors etc, has been capacitor failure,

 

but there are fakes out there too, any suggestions?

Purchase known brands from a reputable source.

 

Hello,

The capsite has a lot of information on capacitors:
http://www.iequalscdvdt.com/

Bertus

 

Electrolytic capacitors come rated at 85⁰C or 105⁰C, therefore always select ones rated at the higher temperature for a longer life.

 

The main problem is that they expire and some build a long time ago are not good as their ESR goes up and power supplies fail. I was told Panasonic last longer. I had that sort of problem they last a few years and break again. Some have the manufacturing date on them.

 

If the caps are old, they can be reformed.

 

The main problem is that they expire and some build a long time ago are not good as their ESR goes up and power supplies fail. I was told Panasonic last longer. I had that sort of problem they last a few years and break again. Some have the manufacturing date on them.

They only expire if they are used. Caps sitting in a drawer will last forever - and an even a few weeks longer if you apply positive constant voltage to "reform" them before using them.

the closer they are held at their rated temperature, the less long they last. But id you keep them 30 to 40°C from the rated temp, they last a long, long time.