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Large Coil SS SG

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  • #16
    Originally posted by min2oly View Post
    Hi Floris,
    I meant to imply that maybe the problem is the battery you are charging and not the circuit?

    perhaps someone with OPTO experience could ask better questions...
    Hey, look at that - I'm a senior member now

    the vid below will dump any size cap you have

    Kind Regards,


    • #17
      Is the circuit that you use posted on this forum some where?


      • #18
        Originally posted by Brian McNece View Post
        Is the circuit that you use posted on this forum some where?
        Hi Brian,
        Thanks for asking. Yes and no...
        that block you seen in the box is a solid state relay. the neg of the cap runs through it and onto the charging battery. the big question is how do I trigger it. I've never drawn it up. I'll have to get to it some time soon. when I do, I'll post it here. It's pretty simple, although I'll have to open it up and take a look at what direction I have things pointed. I'd hate so say something wrong only to correct it later.
        JB said he has his in backwards and it triggers on the break-down voltage, I've never been able to get mine to do that. I tried it w/ many different setups and batteries on the charge side - no luck


        • #19
          Yes Patrick, senior member you might be right. I'll have another go when i'm finished with my current plasma bench project. Cheers.

          Bob, your AGM batteries should work fine with the SSG, the only drawback is that they will dry out in time. To prolong to the lifetime of your deepcycle it is recommended by factory to not exceed 50% discharge. Please lookup the product sheet for your battery to find out what the factory says about that.

          Brian, I'm not sure there is a circuit scheme but have a look at patrick's video's, he has explained things really well.


          • #20
            Using a crt ferrite yoke increased my 6 filar twisted 23 awg wire and like a motor humming specially with the sun in a 12 oc lock position using a 60 w solar panel and 4 60 ah car batteries all converted to alum


            • #21
              Originally posted by Catrinisin View Post
              Hi Bob,

              I also had this same experience charging "dead" UPS batteries from large trays. Using a small SSG with two transistors, I would charge them slowly one by one. At first the voltage was high in the 20's like you said. Then they would come down to normal and subsequent charges looked normal; 11V through 16V when I stop. Yes I said 16V. I've found that charging them all the way to 15.5 or 16 seems to do the best. I have read however that a lot of people stop sooner, like you stated. Is there a reason for this that has escaped me? I just seem to see better results, with "dead" batteries coming back to better than new condition when I charge them to 16V each time. After resting, they come down to about 13.4 or so. When I do C20 rate tests, they always last longer than 20 hours after being cycled to 16V a few times, being drained down to 11V. These are small 9AH 12V batteries from an APC 1500VA UPS in this example.

              I've only been at this for a few months so I don't have a lot of experience to lean on here. If I am causing long term damage of some kind, will someone please set me straight?


              Here is a pic of my small charger referenced above. I mainly use it to charge small AA's and the like, but it seems to do really well with larger batteries that are on the way to recycle.
              Glad to hear that someone else has seen this behavior. It does seem to me that with the AGM UPS batteries that once you get them working decently a charge curve will run up at a steady incline until about 13.5 volts. Just after they get to that point their will be a quick rise to 15 or 16 volts. If you have a meter that charts on the pc it looks like a big hump towards the end. I think if there is any harm in bringing them up to 15/16v it is that you may be causing unnecessary gassing which will dry them up. The AGM's do have electrolyte but it is trapped in the mat material. They are designed to vent if they are over charged.

              Floris thanks for the advice about the batteries. I apologize for jumping into your thread and hijacking it with off topic stuff. I was initially drawn to your large coil because I am also experimenting with larger coils than I had used previously. Yours is very different and very nice I may add! I will be starting a new thread about my new setup and I hope you will come comment on my progress. I am also very interested in the cap dump's you guys are discussing but I don't understand the circuit well enough yet to try and work with one.
              Last edited by BobZilla; 03-16-2013, 12:23 PM.


              • #22
                Large coil SS:

                After falling into my 117 transistor SG board and smoking all the base resistors and a couple of transistors, I went back using 55 transistors with 2 wires on each. These are paralleled. (Coil is 117 strands of #22 ga wire @ about 310 ft.)

                A 555 timer based oscillator with frequency and duty cycle control is used to bias two BD243C transistors, which supply 6vdc to the base of the 55 MJL21194s connected to the SG coil. System output is connected to about 3000AH LABs. Current control is provided by automobile headlamps connected in series/parallel with the supply battery. (24 v @200AH)

                The nicest waveforms appear drawing a bit over 3 amps. Radiant seems to be biasing the MJLs, as varying the voltage to the BD243Cs has no effect.

                This is just a preliminary report, as I just got the thing working this past weekend. Later, I may funnel the supply voltage through a couple of MJLs mounted on a heatsink and pulsed by the same BD243c setup.

                I have a better variable frequency/duty cycle oscillator coming for use in building a 'Source box' containing the oscillator, variable voltage supply, bridge rectifier, volt, and amp meters. Something self-contained that I can move from project to project.

                If time allows, I'll get some pictures and better data this week and post them.



                • #23
                  Originally posted by min2oly View Post
                  I've not tried the opto. I did use the SCR/Zener combo and the SCR would lock up. It took me a while to figure out it would mostly happen with batteries that had high impedance. I've always leaned toward the most simple method possible that takes the least amount of energy from the system to run.
                  This is the best cap dump I've ever used for a SS energizer:
                  Hello Min2oly,

                  Can you post a circuit diagram of this cap dump? It looks really sweet!



                  • #24

                    No, i believe the fully charged standing V on a converted Alum battery is going to be about 11.5V or so....... If well conditioned, they may stand at 12V


                    • #25

                      since i have not had a chance to convert a small LAB to alum, i do not know what the high end V is going be under charge...... maybe soon, if i can ever get over this head cold and sinius's problems i've had for weeks.... i am so far behind on the various projects, it's not even funny.........


                      • #26
                        Mike, I recall From JB's videos he had the charge voltage around 16.5v. Check his videos though - Energenx channel on YT.

                        John K.