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    Overvolting/reversing a polymer cap

    Just curious, have anyone videoed over volt or reverse connected polymer capacitors and posted how they fail?

    IIRC most of the videos I've seen are of cheap wet aluminum capacitors which are fairly spectacular, but what about polymer - do they mainly fail the same way? Or not?

    The wet aluminum capacitors will expand due to vapor generation of the liquid electrolyte and could blast off. Polymer capacitors have two transition phases from solid to liquid and then liquid to gas... so do they do the same thing or simply immolate on board?

    #2
    Re: Overvolting/reversing a polymer cap

    there is a vid on jtube,
    a bussbar with a line of poly's on it - they short out - presumably, because on most the leads melted!!

    Comment


      #3
      Re: Overvolting/reversing a polymer cap

      So they fail like tantalum caps in which they simply short out? hmm... okay...

      Well, after they short then they differ I suppose, tantalum capacitors tend to immolate, but not polys?
      Last edited by eccerr0r; 01-29-2019, 12:58 AM.

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        #4
        Re: Overvolting/reversing a polymer cap

        the poly's may have flared if they had been flush on a board - who knows.

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          #5
          Re: Overvolting/reversing a polymer cap

          heatup and smoke, charred the bottom

          Comment


            #6
            Re: Overvolting/reversing a polymer cap

            Reason why I'm asking:

            Destructive testing to prove a cap is a polymer cap versus an aluminum wet electrolytic

            Comment


              #7
              Re: Overvolting/reversing a polymer cap

              or just cut into it.
              esr test will be conclusive anyway - the worst poly still blows away the best wet caps.

              Comment


                #8
                Re: Overvolting/reversing a polymer cap

                If one doesn't have an ESR meter that has enough resolution, that's not an option...
                Was wondering about cutting into it and sensing any sort of moisture, but that's no fun

                Comment


                  #9
                  Re: Overvolting/reversing a polymer cap

                  Well this is all the inspiration I need, what values did you have in mind and you you be prepared to send said samples for 'testing' I can currently manage 30 volts at 20 amps or 60 volts at 15 amps. Let me know if you want to do this I can video the results

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                    #10
                    Re: Overvolting/reversing a polymer cap

                    Great, you can buy the stj clickbait capacitors to test

                    Comment


                      #11
                      Re: Overvolting/reversing a polymer cap

                      I am not buying perfectly good capacitors to slaughter, but if some one wants to send me some for destructive testing I will be more than happy to oblige and put the results up on my youtube channel. Who knows if there is enough interest I might rebuild my old high voltage capacitive discharge rig which was good well up-to 20,000v.

                      Comment


                        #12
                        Re: Overvolting/reversing a polymer cap

                        Who said they were perfectly good capacitors, that's what we're trying to find out if they are or not

                        So if you had to go buy some brand new Rulycons would they be considered perfectly good capacitors

                        Comment


                          #13
                          Re: Overvolting/reversing a polymer cap

                          lol
                          that psu output sounds familiar.
                          is it military surplus?? wayne kerr???

                          Comment


                            #14
                            Re: Overvolting/reversing a polymer cap

                            It's been 10 years or so, but I think that when I tortured some polymer caps - 8X or 10X their ripple current rating - they just deteriorated slowly. I probably declared victory when they reached 2X their initial impedance.
                            PeteS in CA

                            Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
                            ****************************
                            To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
                            ****************************

                            Comment


                              #15
                              Re: Overvolting/reversing a polymer cap

                              Heh, the intent for killing these "clickbait" polymer caps was to compare how they explode compared to wet aluminum capacitors to determine their internal design. Yeah it's not accurate at all but there's at least one person here who's interested in watching them explode if at all...

                              Question too for using more current than they're designed to handle is how long did it take at 9x current rating to reach 2x impedance... 1/10 of their rated lifetime? 1/100th?

                              Comment


                                #16
                                Re: Overvolting/reversing a polymer cap

                                Well I have put the offer out there, Uk mailing address to be supplied via private message to interested party's. If you want to send me a selection of test subjects I will oblige in over volting and reverse volting them for your viewing pleasure. Bench test voltages available in case you missed are 30 volts @ 20 amp and 60 volts & 15 amp, results to be published on my youtube channel. The 20,000 rig was probably mostly military surplus parts I still have some of the parts but would have to hunt around to resurrect it, oh fond memories.
                                Last edited by llonen; 02-02-2019, 09:44 PM.

                                Comment


                                  #17
                                  Re: Overvolting/reversing a polymer cap

                                  Darn, already done ... https://www.youtube.com/watch?v=BNaVokFOxjo

                                  So all I need to do is abuse it and it better not pop, just short out...

                                  Comment


                                    #18
                                    Re: Overvolting/reversing a polymer cap

                                    Needs more voltage, or lower voltage polys, I have had another look at the power supplies I have here, I can get up-to 60 volts with 32 amps available, on the high voltage side I can relatively easily get up-to 10kv @ 1uf. That will be around 50 joules assuming I can get it to full charge, it looks though I no longer have the 20kv caps though. I wont be checking this thread now so if there is any interest just pm me.

                                    Comment


                                      #19
                                      Re: Overvolting/reversing a polymer cap

                                      And if not, "I ain't having it, where's my hammer?"

                                      Comment


                                        #20
                                        Re: Overvolting/reversing a polymer cap

                                        Originally posted by eccerr0r View Post
                                        ...
                                        Question too for using more current than they're designed to handle is how long did it take at 9x current rating to reach 2x impedance... 1/10 of their rated lifetime? 1/100th?
                                        Pretty sure it was hundreds of hours if not over a thousand. Not bad for 2000 hour (at max ripple and temp) parts. It was ~10 years and two jobs ago, so hazy memories.
                                        PeteS in CA

                                        Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
                                        ****************************
                                        To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
                                        ****************************

                                        Comment

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