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  1. tatus1969

    kWeld - "Next level" DIY battery spot welder

    yes it is, but I am quite busy with the new pro welder and also other projects for customers and therefore I am a bit slow in answering. And I also don't work over the weekends :-) Cheers Frank
  2. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I mean a welding pen that doesnt stick ormelt from the high power that kWeld provides. Would be worth a try. C14500 is known to melt later and stick less.
  3. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I'd say find or make a more powerful welding probe, and/or contact the seller. What are you welding with them? They should be suitable for 0.1mm nickel but not more, as they are quite thin.
  4. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The overcharge protection is not directly related to the capacitor type, as there are multiple revisions with Maxwell, some without and some with the protection. You can tell that the board has protection by the presence of a small black heatsink in the control section. The protection cuts off...
  5. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Hi guys, just wanted to give a sign of life here - Happy New Year! :-) :-) Somehow my topic notifications go into the spam folder and therefore I wasn't notified a long time... A lot has happened in this forum since, if there is anything where I should respond then I'd be happy if that user...
  6. tatus1969

    kWeld - "Next level" DIY battery spot welder

    They do, but they also represent an inductor. And that is what then kills the unit 8)
  7. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The SMDJxxA must be placed at the left of the unit, close to where the original part was. Put the new large TVS at its original position, and add thick jumper wires from there to the rightmost MOSFET (left 5 legs). Make sure to leave out the short tab in the middle. When seeing your battery...
  8. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The SM8S26A looks like an OK replacement for the large SLD8S28A, but for a SMDJ28A it is overkill (but would of course work). Instead of SMDJ28A you can also use one of the other voltages starting from 24V. But as you keep killing the parts, something else must be horribly wrong. I suspect that...
  9. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The burnt track suggests that the large TVS diodes at the right might be bad as well. These are Littelfuse SLD8S28A. Your replacement parts can't be used as their voltage ratings are too high. Depending on your battery voltage, you can go to lower voltage devices such as SMDJ24A (Digikey has a...
  10. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I have had other requests in the same direction, and can make a test firmware if someone volunteers :-) The challenge here is that it is not allowed to interrupt the flowing current, before it has dropped below the safe 2000A. This means that the pulse energy will have a lower limit. Also...
  11. tatus1969

    kWeld - "Next level" DIY battery spot welder

    In many cases this also means that you either have 15 nickel strips in parallel, or one big custom one spanning everything.
  12. tatus1969

    kWeld - "Next level" DIY battery spot welder

    You can lower the batt voltage just for calibration (the current there is higher because the work piece's electrical resistance is missing) then top it up again for normal use. Or use it at 50% in order not to risk random overcurrent abortions during welding, which would be embarrasing.
  13. tatus1969

    kWeld - "Next level" DIY battery spot welder

    pardon?
  14. tatus1969

    kWeld - "Next level" DIY battery spot welder

    When using the full 2kA, you cannot extend the battery leads as that introduces extra inductance. Please make sure to have read the user manual chapter discussing that. The calibration only "looks" at the output side of the unit, it doesn't care how you wire up the battery. That said it is...
  15. tatus1969

    kWeld - "Next level" DIY battery spot welder

    This forces thousand amps through the logic board, which usually breaks the ground connection (look underneath the board for burn marks). If that has happened, then the board is beyond economic repair as this causes most chips to fail. Also, the MCU is preprogrammed with a custom encrypted...
  16. tatus1969

    kWeld - "Next level" DIY battery spot welder

    What is your professional background to make that statement?
  17. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I fully disagree - doing that is exactly what creates the repeatability that kWeld is known for.
  18. tatus1969

    kWeld - "Next level" DIY battery spot welder

    In general terms, the unit measures the power that is put into the weld spot. In detail, that is what differentiates kWeld from other solutions :-)
  19. tatus1969

    kWeld - "Next level" DIY battery spot welder

    That is a Littelfuse SMDJ28A.
  20. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I am :-) Meanwhile I have graphical LCD code in my toolbox, made for another project (using lvgl). The feature list for a kWeld2 is long, all is missing is time. At the moment I am fully loaded with customer projects till beyond end 2021...
  21. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Just seeing this now, somehow the ES email notifications don't arrive anymore since a while... Bench supply conversion requires removal of the two trimmers and soldering two 10k linear pots. Current limiting is a bit voltage dependent because the circuit uses PWM peak current limiting, and...
  22. tatus1969

    kWeld from Keenlab now available in the US

    No problem, just tell me your keenlab order number and I'll cancel+refund. Just important to mention, both me and all my resellers are out of stock at the moment. That's all your fault because you're all ordering quicker than I can resupply. Just kidding :-) I'm expecting replenishment this week.
  23. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Interesting idea :-) Don't expect too accurate results please, as kWeld isn't a precision istrument. I use to measure low resistances with a bench power supply and a multimeter: set the supply to as much current as possible and connect it to the ends (I have decent crocodile clips for that)...
  24. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I'd say your theory is spot on, the copper strips have significantly less resistance and push the current above the limit. I'd also try using partially discharge batteries first.
  25. tatus1969

    kWeld - "Next level" DIY battery spot welder

    That sounds like an amazing option for kWeld, since that battery delivers more than enough current while still being considerably smaller than a regular 65AH/100AH starter battery (at least what I can tell from your picture). Please tell me the amount of current that you get during welding, I'd...
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