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  1. tatus1969

    kWeld - "Next level" DIY battery spot welder

    aarrgh, again... checking, https://hobbyking.com/de_de/turnigy-graphene-6000mah-3s-75c-lipo-pack-w-xt90.html https://hobbyking.com/de_de/graphene-5000mah-3s-75c.html are shown as 'in stock' but with just a few of them. I guess I need to make more test buys soon...
  2. tatus1969

    kWeld - "Next level" DIY battery spot welder

    yeah, good point. Any idea how to explain that to 10,000 customers? ;-)
  3. tatus1969

    kWeld - "Next level" DIY battery spot welder

    not yet, but we are making a first batch of 20 right now. I hope to be able to open up for preorders before Christmas. The first units will be kits, and I might have a price point in one or two weeks from now. Software will be limited when they get released, but we are and will remain working...
  4. tatus1969

    kWeld - "Next level" DIY battery spot welder

    that would require a firmware extension as kWeld does not have a proper automation interface. It has been requested many times, but I just never hav gotten to that :-/ kWeldPro will definitely have that - automation via USB, and also a digital input/output interface for use with CNC machines...
  5. tatus1969

    kWeld - "Next level" DIY battery spot welder

    sorry, just seeing this now. kSupply can be paralleled, so upping the current is quite easy. Two to three of them in parallel, with a server power supply for each of them, would allow for maybe 250 amps short time. Might actually be an interesting approach.
  6. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I wasnt able to progress as fast as I wanted, because we had to do firefighting for weird firmware bugs in a customer project, literally for several months in a row. Conclusion: Wireshark does not see everything bad happening on USB, but thanks to the makers of the Beagle USB sniffer we managed...
  7. tatus1969

    kWeld - "Next level" DIY battery spot welder

    that's definitely what I am shooting at - pure copper strips on aluminium cell cans. I'll conduct a few tests soon and post my results here.
  8. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Thanks guys, you are amazing. I would never have realized that it is the peltier effect causing this. This also explains why I could never reproduce your observations - the Peltier effect depends on the material combination, and the pulse duration also appears to play a role. Now, with kWeldPro...
  9. tatus1969

    kWeld - "Next level" DIY battery spot welder

    That will require a custom enclosure (I'll publish 3D models to start from) but is no problem. Not sure why you would want this however, as it is not the capacitance but the resistance that we need from them. The "small" ones already deliver 4500A during calibration. Also, changing the charge...
  10. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Attached is the voltage regulator. The trimmer sets the reference voltage, and V+ is the kSupply's output voltage. From that you can calculate the values. You can use R3 and R7 to mount the fixed resistors.
  11. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I had done that and tested, and found that there is no improvement. kWeld delivered perfect and repeatable results without the cleaning pulse, no matter what I do. Also the community gives me this feedback. If you keep having trouble then please contact us and we'll check your setup and guide...
  12. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The energy metering approach of kWeld (which eliminates the need of having 1 or 2 softening pulses) assumes that the power source doesn't vary that much. This is because 1500A means roughly double welding power than 1000A. Consequently you get the same variation in pulse duration. The longer the...
  13. tatus1969

    kWeld - "Next level" DIY battery spot welder

    (english for the other guys :-) Happy to hear that, I should have roughly 10 prototypes within the next 2 to 4 months (I need to stretch my time sometimes due to other projects) and plan to start a poll once ready.
  14. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I plan to sell assembled and tested units (with EMC and safety certification later on) as well as kits. I already have a laser-cut sheet metal enclosure here on my desk, form example. There will be a kit that includes the capacitor module, and also one without. It will be possible to mount a...
  15. tatus1969

    kWeld - "Next level" DIY battery spot welder

    That is ok for slower casual welding, but you should watch the connector's temperature while doing that.
  16. tatus1969

    kWeld - "Next level" DIY battery spot welder

    These Lipo chargers do not provide accurate results, and also they surely include their own lead and croco clip resistance. For an accurate result, I use my oscilloscope and a strong load. Measure batt voltage with an without load, calculate ESR from that.
  17. tatus1969

    kWeld - "Next level" DIY battery spot welder

    does this mean that you don't get a double beep error when you set "MinCurr" like this? That shouldnt be the case!
  18. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Use thick copper braid to make the connection, make sure not to touch the sixth terminal (gate). I'd also check the small resistor and diode, as they have received some heat.
  19. tatus1969

    kWeld - "Next level" DIY battery spot welder

    While not knowing the exact specs of that battery, I'd say that it is way too powerful for the welder. kWeld has an overcurrent protection, but when a battery is just pushing way too much then that doesn't trigger quickly enough. Important to note that the welder basically shorts out the battery...
  20. tatus1969

    kWeld - "Next level" DIY battery spot welder

    As Hobbyking is often out of stock on my recommended Lipos, I've bought and tested a few more models. I can recommend these two: Turnigy Nano-Tech Plus 5000mAh 3S 70C Lipo Pack w/XT90 (calibrates at 1570 amps when fully charged) Turnigy Graphene Panther 5000mAh 3S 75C Battery Pack (calibrates at...
  21. tatus1969

    kWeld - "Next level" DIY battery spot welder

    My intended price tag is around 1000€ for the prebuilt base unit. Power supply and output cables are extra items. I also have the idea to offer the base board for people wanting to mount their own ultracapacitors (actually kCap will also work with the new unit), but I'm not fully sure. I...
  22. tatus1969

    kWeld - "Next level" DIY battery spot welder

    The unit will come with a 450W power brick (18V / 25A), but you can also operate it from a battery. The onboard ultracap charger is designed for 60 amps, and that should allow for 200 Joules per second at the output terminals. The cable losses will reduce this, but for copper one could use...
  23. tatus1969

    kWeld - "Next level" DIY battery spot welder

    Part of that is that the unit will have a touch TFT, which requires lots of pins and power, but part of that is also lots of things to control. The unit has a built-in 4S ultracap charger with balancing and thermal monitoring, and lots of other process variables.
  24. tatus1969

    kWeld - "Next level" DIY battery spot welder

    First sight 8)
  25. tatus1969

    kWeld - "Next level" DIY battery spot welder

    I'd love to give laser welding a go, maybe as the second next project? ;-)
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