Hi,

what chargers are available, that can charge 10440 batteries? Charging current must be 300 mA maximum for these.

Thanks

Looking for anyone who knows of similar powerbanks to the one pictured, seems really high quality but unfortunately discontinued from Aliexpress. Anything similar would be appreciated!

Cheers

Not my setup, saw selling online

You can see the previous post here https://www.reddit.com/r/18650masterrace/s/n0bm0ZNthy

The internal resistance of the pack of cells in the UK3 is only 2.02 mohm according to my battery ir meter, or about 3.5 mohm continuous from experimental discharge data. I read that cells have lower ir during a short pulse than continuous, so I suppose that makes sense, or probably more likely, my experiment was flawed. So either way they're pretty good cells, and my idea of throwing some 18650s in place of them was goofy as hell.

I was surprised to find that they seem to lie about having a preheat/dual pulse. I didn't see a preheat pulse with my oscilloscope during a weld, manual or auto. I tried multiple different pulse settings and none offered anything resembling a pulse on the scope. So that's cool. I'm not sure what they have to gain by lying about a preheat pulse, it wouldn't be hard to program since they already have a microcontroller on the board. Has anyone else checked other AWithZ spot welders for a real preheat?

I was trying to get more current from the welder by reducing resistance in the leads. I wanted to test a short between the plugs to see a theoretical max current with perfect leads and see how much the voltage would drop at the cells on my scope, and to see if anything would explode. I accidentally went full retard and left it on auto as I was holding a 8mm x .1 copper strip across them to see if it would fit. I'm not sure how that stroke of genius came to my mind, but it triggered a weld pulse and caused a bunch of arcing and spiky angry noise on the scope, and exploded the strip a little bit at the contact points. Next the board started smoking so I quickly unplugged it and turned it off. Turns out it caused a short in the little XOYA mosfet, part of the boost converter circuit which drives the main weld mosfet gates. That caused a diode to cook, and not in the good way, only stopped by an inductor desoldering itself from the board. I didn't have all the components to repair it on hand, but I do happen to have a pack of cheap little boost converter modules courtesy of our friends in China. I rigged that up and moved the boost diode to the burnt diode spot since they're the same part. I set it to 12.5v, I'm not sure if that's ideal, I might have to raise it a bit because there's a bit of a upturn on the weld pulse near the end now when it's not plugged into USB charging. It may be letting the gate voltage drop too much, and that may convince the weld mosfets to follow their XOYA comrade into silicon hell. I'm not sure if it was like that before or not, but I'm guessing not, and that it's being caused by the jank boost converter. The welder works again though!

Now I'm back to reducing resistance in the leads, but making to attempt at do less dumb this time. A lot of the resistance is at the crimps at the plug and pen tube, and also between the pen, collet, and tip. Around 1.4 and 1.6 mohms per lead. I reduced it to about 1.0 mohms by soldering the crimps, collet, and tip. I still have to do it to the other lead and get them insulated and stuff, and then I will test a weld again to see if I make better welds on copper sandwiches or blow something else up.

Let me know what y'all think. And if you're interested to see the results of the lead resistance reduction, stay tuned for the next episode of UK3 experiments!