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  • Simple Cap Dump

    Somebody on the old forums had posted up a schematic (or maybe it was just instructions) for essentially using a transistor with no tigger to do a really simple cap dump. For the life of me, I can't find those posts any more, and I can't seem to find anything in my personal collection.

    As far as I can remember, it pulsed the negative side, you basically put the cap in parellel with the battery, and transistor was between the negative pole on the battery, and the negative lead on the capacitor. I just can't remember which side of the transistor went to which. At a certain point the transistor would break down, and pulse the battery, usually dropping the voltage on the cap by 12-15 volts. I do remember with the MJL21194 it broke down at about 36 volts, and if you started putting voltage on the cap without having the charge battery connected it would fry the transistor immediately. Trying not to fry any transistors figgering this out. . . .

    Anybody remember what I'm talking about?

  • #2
    Hi Aram. I wonder if the wiring would be the same as the triggered cap dump from the diagram supplied with the 3PM. I am looking for a circuit using the 555 to do the same thing if any one has a relevant circuit or PCB design I will be most appreciative.
    Clyde James

    Comment


    • #3
      Is this what you people looking for ?? brushlessenergizerlk8.jpg

      Comment


      • #4
        Originally posted by Aram View Post
        Somebody on the old forums had posted up a schematic (or maybe it was just instructions) for essentially using a transistor with no tigger to do a really simple cap dump. For the life of me, I can't find those posts any more, and I can't seem to find anything in my personal collection.

        As far as I can remember, it pulsed the negative side, you basically put the cap in parellel with the battery, and transistor was between the negative pole on the battery, and the negative lead on the capacitor. I just can't remember which side of the transistor went to which. At a certain point the transistor would break down, and pulse the battery, usually dropping the voltage on the cap by 12-15 volts. I do remember with the MJL21194 it broke down at about 36 volts, and if you started putting voltage on the cap without having the charge battery connected it would fry the transistor immediately. Trying not to fry any transistors figgering this out. . . .

        Anybody remember what I'm talking about?
        Hi,

        I think you may be referring to a MOSFET circuit that has recently been shared. My understanding is that this circuit works because of the internal diode inside the MOSFET breaks down at a set voltage. This internal diode is not present in the transistor, as far as I'm aware the transistor will not fire unless it is triggered to do so. The circuit presented above is perhaps the easiest way to charge off the capacitor, though it is strictly speaking not a true cap pulsing circuit.

        Still it is based on one of Johns schematics, I've had good success with it in the past. The SCR works well like this, but can latch on or cause undesired results when a larger capacitor is used and one triggers it to pulse discharge. With the diode and resistor as shown it tends to keep the cap at a set voltage above the battery, depending on the strength of your energizer. On my small model the cap sat at 1.5v higher than my battery at all times.

        Worth a tinker with IMO

        Regards

        Comment


        • #5
          Simple Cap Dump

          Hi Aram,
          I posted it on the monopole2 group last Dec. , here it is again.

          Cap, Battery , Diode and NPN.
          The SCR cap dump works but is real finicky. This one seems to works good over a wide range of imputs and cap sizes. The NPN is hooked up with collector to neg of cap and the emitter to neg of battery, no base connection. Battery and cap positives connected together. Different NPN's dump at different voltages. I've tried 4 NPN's so far.

          MJL4281 switched at 24v down to 20v
          MJL21194 switched at 33v down to 24v
          MJW18020 25v to 20v
          NJL3281 23v to 19v.

          I've use caps from 10uf to 68000uf.
          The scope shot in my album is a NJL 3281 dumping a 15000uf cap between 23v peak to 19v bottom at about 4 times a sec.
          2volts into a SSSSG to charge the cap it would dump every 28 secs, depending on cap size and voltage I've had it dump 66 times a sec.
          It seems stable over a wide range of cap sizes and voltages.
          As soon as we get some sun I want to try it on some of my solar pannels, both just the pannels charging the cap and the pannels running a SSSSG to charge the cap.
          (+_+)



          updated_schematic.jpg

          I currently have 2 of these running on a 4filer, 1 trigger,1power,2 output windings.
          Each output winding goes through diodes to seperate simple cap dumps with 35,000uf caps and MJL4281A's which are each charging a pair of L16's

          Mike Klimesh

          Comment


          • #6
            That was it, thank you!!!

            Comment


            • #7
              That's a new one on me Mike K. Thanks for sharing.

              al

              Comment


              • #8
                Originally posted by Mike Klimesh View Post
                Hi Aram,
                I posted it on the monopole2 group last Dec. , here it is again.

                Cap, Battery , Diode and NPN.
                The SCR cap dump works but is real finicky. This one seems to works good over a wide range of imputs and cap sizes. The NPN is hooked up with collector to neg of cap and the emitter to neg of battery, no base connection. Battery and cap positives connected together. Different NPN's dump at different voltages. I've tried 4 NPN's so far.

                MJL4281 switched at 24v down to 20v
                MJL21194 switched at 33v down to 24v
                MJW18020 25v to 20v
                NJL3281 23v to 19v.

                I've use caps from 10uf to 68000uf.
                The scope shot in my album is a NJL 3281 dumping a 15000uf cap between 23v peak to 19v bottom at about 4 times a sec.
                2volts into a SSSSG to charge the cap it would dump every 28 secs, depending on cap size and voltage I've had it dump 66 times a sec.
                It seems stable over a wide range of cap sizes and voltages.
                As soon as we get some sun I want to try it on some of my solar pannels, both just the pannels charging the cap and the pannels running a SSSSG to charge the cap.
                (+_+)



                [ATTACH=CONFIG]542[/ATTACH]

                I currently have 2 of these running on a 4filer, 1 trigger,1power,2 output windings.
                Each output winding goes through diodes to seperate simple cap dumps with 35,000uf caps and MJL4281A's which are each charging a pair of L16's

                Mike Klimesh

                I tried this circuit and found it would only charge my 5ah motorcycle battery to around 13.12v and then it gave up. The primary continued to discharge, but no further charging was evidenced in the secondary. The 10uf 250v cap did the best. I also tried a 1200uf 200v, a 1500uf 200v and a 560uf 400v cap. When going diode direct straight radiant, the battery can charge up to 15.8v on a single charge of an identical battery.

                Has any one else run into this problem? Any ideas why it's not working for me?

                Thanks,

                -Woody
                "It's not a mutiny if the commander is leading it!" - Wally Schirra, Commander Apollo 7

                Comment


                • #9
                  Originally posted by Woody View Post
                  I tried this circuit and found it would only charge my 5ah motorcycle battery to around 13.12v and then it gave up. The primary continued to discharge, but no further charging was evidenced in the secondary. The 10uf 250v cap did the best. I also tried a 1200uf 200v, a 1500uf 200v and a 560uf 400v cap. When going diode direct straight radiant, the battery can charge up to 15.8v on a single charge of an identical battery.

                  Has any one else run into this problem? Any ideas why it's not working for me?

                  Thanks,

                  -Woody
                  what voltage is the cap dumping at? if its only dumping at 14 or 15 it may not have enough potential, I like to see the cap dump at twice the battery voltage.

                  Tom C


                  experimental Kits, chargers and solar trackers

                  Comment


                  • #10
                    Originally posted by Tom C View Post
                    what voltage is the cap dumping at? if its only dumping at 14 or 15 it may not have enough potential, I like to see the cap dump at twice the battery voltage.

                    Tom C

                    Hi Tom. Thanks for the reply.

                    With the larger caps the voltage range was a high of about 35v dumping down to about 30v. Interestingly, the 10uf 250v cap went to about 17.9v and just stayed there. My MJL21194 transistor got pretty warm, about 140F. Also, I am using a 3a 1000v diode. Besides the transistor, all other components are cool to the touch.

                    -Woody
                    "It's not a mutiny if the commander is leading it!" - Wally Schirra, Commander Apollo 7

                    Comment


                    • #11
                      Hi Woody

                      I did try Mikes circuit and toasted a couple of different transistors including 2 x MJL21194 (I was not happy) was using 3300uF 360V cap charged straight from RE diodes from the SSG, did not get much joy to see the end results as the trannys toasted before seeing any results,


                      You can try JohnK and ask him about the new "Flux-capacitor Pulsar", or

                      http://www.energyscienceforum.com/be....html#post5398

                      Theunis
                      Hey !
                      WHAT HAVE YOU DONE WITH THE PORTION OF SOLAR ENERGY THAT WAS ALLOCATED TO YOU TODAY? !
                      JUST THINK ABOUT IT . . .

                      Comment


                      • #12
                        Originally posted by Tom C View Post
                        what voltage is the cap dumping at? if its only dumping at 14 or 15 it may not have enough potential, I like to see the cap dump at twice the battery voltage.

                        Tom C
                        your tranny is just passing current..... the heat you see in the tranny is where your primary discharge current may be going...hmmmm. tranny swap? I dont fully understand why that transistor is switching , there must be a breakdown voltage of the c/e junction, if you are not switching the base. I am going to try this tonight.
                        mike any help here?


                        Tom C


                        experimental Kits, chargers and solar trackers

                        Comment


                        • #13
                          Originally posted by Tom C View Post
                          your tranny is just passing current..... the heat you see in the tranny is where your primary discharge current may be going...hmmmm. tranny swap? I dont fully understand why that transistor is switching , there must be a breakdown voltage of the c/e junction, if you are not switching the base. I am going to try this tonight.
                          mike any help here?


                          Tom C
                          Swapped out the tranny.. Same results. 160F Temperature on the tranny, and battery topped out at about 12.98v. Was charging a 7ah gel with a 13ah gel and the big 13ah battery went down to less than 12v just trying to get that 7ah to where it did get to. Lots of wasted energy heating up that transistor. Straight off the diode I could have had that battery up over 16v with that 13ah battery on the primary side. Cap was a 560uf 400v. Not too impressed with this circuit, but I must be doing something wrong...

                          -Woody
                          "It's not a mutiny if the commander is leading it!" - Wally Schirra, Commander Apollo 7

                          Comment


                          • #14
                            Mike's Circuit

                            Hi Guys

                            You need to rectify the RE, see attached this way it runs cold no heat-sink,

                            Each transistor has a different break down voltage as explained by Mike.

                            (Sorry I was confused before, was not running straight from RE was thinking of something else)

                            Theunis
                            Attached Files
                            Last edited by Prinsloo; 02-05-2013, 11:32 PM.
                            Hey !
                            WHAT HAVE YOU DONE WITH THE PORTION OF SOLAR ENERGY THAT WAS ALLOCATED TO YOU TODAY? !
                            JUST THINK ABOUT IT . . .

                            Comment


                            • #15
                              Originally posted by Mike Klimesh View Post
                              Hi Aram,
                              I posted it on the monopole2 group last Dec. , here it is again.

                              Cap, Battery , Diode and NPN.
                              The SCR cap dump works but is real finicky. This one seems to works good over a wide range of imputs and cap sizes. The NPN is hooked up with collector to neg of cap and the emitter to neg of battery, no base connection. Battery and cap positives connected together. Different NPN's dump at different voltages. I've tried 4 NPN's so far.

                              MJL4281 switched at 24v down to 20v
                              MJL21194 switched at 33v down to 24v
                              MJW18020 25v to 20v
                              NJL3281 23v to 19v.

                              I've use caps from 10uf to 68000uf.
                              The scope shot in my album is a NJL 3281 dumping a 15000uf cap between 23v peak to 19v bottom at about 4 times a sec.
                              2volts into a SSSSG to charge the cap it would dump every 28 secs, depending on cap size and voltage I've had it dump 66 times a sec.
                              It seems stable over a wide range of cap sizes and voltages.
                              As soon as we get some sun I want to try it on some of my solar pannels, both just the pannels charging the cap and the pannels running a SSSSG to charge the cap.
                              (+_+)



                              [ATTACH=CONFIG]542[/ATTACH]

                              I currently have 2 of these running on a 4filer, 1 trigger,1power,2 output windings.
                              Each output winding goes through diodes to seperate simple cap dumps with 35,000uf caps and MJL4281A's which are each charging a pair of L16's

                              Mike Klimesh
                              Mike, why the added diode to the + on charge battery?

                              To all:
                              many were trying this out on MP2 a while back.
                              ever try adding another transistor or 2 in parallel? series? different trannys have different break down...
                              we also used this to trigger a solid state relay to handle more current on the big boy - comparator works much better though. This is fun to try out, but that comparator ckt of JB's is the one to go for.
                              Paul put up a good drawing of it here there are some on the old Ferris Wheel thread has some drawings as well. I don't know if anyone has put one up on this forum.
                              Cheers,
                              Patrick

                              Comment

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