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  1. nemo

    Build your own CD battery tab welder for about $100.00+-

    Great stuff and very proffesional. Actually I'm inspired to close mine inside the box now. My welder is electricaly finished . I did manadge to solve the mosfet failing. I soldered together not only a mosfet driver inputs but also their gate output. This way I can be certain that the mosfets are...
  2. nemo

    Build your own CD battery tab welder for about $100.00+-

    For a soft copper I used a new cobalt coated drill bits ,vice and hand held drill. I pre-drilled it 3.5mm and went to 6.5 after that. I always use a torque setting on the drill.This saved my drill bits from breaking when getting stuck. As to my mosfet welder I burned 4 of 24 mosfets. I'm going...
  3. nemo

    Build your own CD battery tab welder for about $100.00+-

    Many months ago I submited my mosfet 12Farad dual pulse welder here. I burned half of the 24 the mosfets after a few welds, ouch....., fixed it again put a protective devices(huge 2 doublediodes and varistors) and fired it againg yesterday everning. And guess what ! It seems to be fine. Now I...
  4. nemo

    Using RC motors on E-bikes [Archive]

    Do you have a picture of this freewheel ? I'm interest to see it. Thank You
  5. nemo

    Using RC motors on E-bikes [Archive]

    I think that their setup is fine for a motor that is pulling but when coasting the small wheel will need to rotate at about 7000rpm. And at this speed the clutch bearing will put quite some resistance. Not good when batteries/gas run out. I would use the ring and cut out the mounting part and...
  6. nemo

    Using RC motors on E-bikes [Archive]

    Jeremy, I had the same idea about using hall sensors in BLDS sensor less motors for modelers and then saw your post here in this thread. Hall sensors are cheap and I don't believe you can synchronize controller and motor better than using them, especially when taking off and under a heavy load...
  7. nemo

    Shenzhen (ecrazyman) Controller Information

    Can somebody please sum up the findings about this cheap controller? The thread is way too long now. I'm interested if this controller (after the resonator change, speed mode) is a replacement for my old good crystalite 72V 35A controller . . I want to drive puma motor at about 50V . Has anybody...
  8. nemo

    Shenzhen (ecrazyman) Controller Information

    Can somebody please sum up the findings about this cheap controller? The thread is way too long now. I'm interested if this controller (after the resonator change, speed mode) is a replacement for my old good crystalite 72V 35A controller . . I want to drive puma motor at about 50V . Has anybody...
  9. nemo

    Build your own CD battery tab welder for about $100.00+-

    There is an additional advantage of having a welder that can shut off the current after the weld is done.( rather than just leaving it on until the caps are discharged). Your caps are recharged much more quickly ! The welding takes shorter time (safer for the cells).More control. Pre-weld...
  10. nemo

    Build your own CD battery tab welder for about $100.00+-

    I think that this might be the case.(don't know for sure!)It also can make welding easier since the extra flexibility of the metal. back to the welder: I think I have found suitable varistor at last...
  11. nemo

    Build your own CD battery tab welder for about $100.00+-

    I'll do a research and try them. It was quite interesting to see that big inductance voltage spike being cut at exactly 24V by the diodes (curve on the oscilloscope). 5 in parallel failed at about 8V, 7 in parallel at 11V. Never all of them!.So your theory is correct.Some were taking a bigger...
  12. nemo

    Build your own CD battery tab welder for about $100.00+-

    I'm BACK!!!!!!!!! PARTIAL SUCCESS WITH MOSFET BASED WELDER AND MORE INFO ABOUT THE PROBLEMS WITH A HUGE INDUCTIVE CURRENT FLOWING BACK TO MOSFETS Today I repaired my humble welder!!! 24 mosfets in, few hours of soldering! and 5 ! protective diodes in parallel , each able to sink 400A/10ms...
  13. nemo

    Build your own CD battery tab welder for about $100.00+-

    Pure Nickel. A great job Jeremy with the welder. I have 10pcs of surge protective diodes 5KP20A. If you need any let me know! The specs looks promising, hope they protect mine welder when finished.
  14. nemo

    Build your own CD battery tab welder for about $100.00+-

    Wow, very neat and nice work! Reminds me of something ! :-) As for copper drilling I used a sharp (brand new) set of cobalt plated drills and hand held battery powered drill. Went ok, didn't loose a single drill mainly because I set a moderate torque.It did help to prevent a drill damage after...
  15. nemo

    Build your own CD battery tab welder for about $100.00+-

    Jeremy, I think that there is a reason for not using copper alloys when battery pack making. Firstly you need a better electrodes (more expensive) and they need to be resharpened. If made of copper this is easy, if made of elkonite it's harder because of the hardness of the alloy. Then the...
  16. nemo

    Build your own CD battery tab welder for about $100.00+-

    Here is the source.(after a long search) http://www.futurealloys.co.uk had 1 off cut rod about 12 inch long 1/4inch dia that I'm getting. I'm not sure but they might be able to order more. They should have my cheque by now and hopefully will post it soon to me. So pleeeeeeeeease don't take that...
  17. nemo

    Build your own CD battery tab welder for about $100.00+-

    Thank you ( RTL) for sharing all the information here again! A great sum-up. I suspected that copper welding is hard. I'm still going for a mosfet switch. This time with a protection against high voltage spikes. I have also ELKONITE 1/4inch rod on the way to me. When the welder is finished...
  18. nemo

    Build your own CD battery tab welder for about $100.00+-

    I have found some info about TVS (transient voltage suppressor) here: http://www.microsemi.com/micnotes/125.pdf Some more info here: http://www.littelfuse.com/data/en/Application_Notes/an9768.pdf I would go for couple of parallel 5kp20a zenner diodes...
  19. nemo

    Build your own CD battery tab welder for about $100.00+-

    I'll post more photos and schematics.I can't afford this to loose mosfets again and maybe we together can find the solution to reliable mosfet super-switch. I used 24 irf2804 (up to 40V) datasheet here: http://pdf1.alldatasheet.com/datasheet-pdf/view/92816/IRF/IRF2804.html Thinking of using...
  20. nemo

    Build your own CD battery tab welder for about $100.00+-

    Finally, I finished the welder. The setup is 12Farad power acoustic caps, 24 mosfets irf2804 , 6 mosfet drivers, thick wires gauge 0,3x 555 on a separate sequential timer board so I can set 2 independent pulses and break length. All done with a minimum resistance, as you can see there are huge...
  21. nemo

    Build your own CD battery tab welder for about $100.00+-

    I didn't finished my setup today !, No time now ! Sorry! So the result will be posted here with the photos on the 10th may when I get back from my travel. It is a dual 24 mosfet based welder with 2 independent pulses and changable delay, with huge cables, huge electrodes and 4.6kg of caps. see...
  22. nemo

    Build your own CD battery tab welder for about $100.00+-

    Today I got 2x 6 farad car caps in the post. It means 8 caps in parallel from power acoustic , total of 12 farad to play with. The 24 mosfet swith is working fine. I abandoned the idea of using 1x 8farad cap after trying it, too week. Then I tried 3x 1.5 farad, better, could just about spot...
  23. nemo

    Build your own CD battery tab welder for about $100.00+-

    I have some progress here(8F 24parallel mosfet based CD dual pulse welder) The super 9A peak mosfet drivers TC4422 are on the way to me from the USA, 4x 555 timer works as planned.See the picture. I'll add 2 more 555 timers and all the logic will be ready. How will it work? First waveform shows...
  24. nemo

    Crystalyte Controllers - Repair and Modification information

    Thank You, I'll try to confirm this from the schematic when I finish it. Nemo
  25. nemo

    Crystalyte Controllers - Repair and Modification information

    Thank You, I'll try to confirm this from the schematic when I finish it. Nemo
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