Search found 299 matches

by tatus1969
Nov 06 2019 5:02am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

ElectricGod wrote:
Nov 05 2019 6:11pm
After seeing that elephant and pile of poo picture, I'm wondering how that elephant did that in one "squatting".
Deduct 20% of that mass to account for that poor guy underneath :wink:
spinningmagnets wrote:
Nov 05 2019 8:16pm
Trying to find time to finish desired experiments.
Exciting! :bigthumb:
by tatus1969
Nov 05 2019 5:40am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

ElectricGod wrote:
Nov 04 2019 2:16pm
Image
Ahemm... can I get this reward paid out cash instead? 8) 8)
by tatus1969
Nov 01 2019 6:58am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

spinningmagnets wrote:
Oct 29 2019 2:39pm
"...would you mind commenting on probes. I imagine somewhere in the thread you have, but I''m at a loss finding that. Are any of these materials a potential improvement?..."

The kWeld electrode holders are ...
Thanks Ron, I was about to answer but nothing to add to this :D
by tatus1969
Oct 29 2019 6:24am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: KWeld and reflow solder paste

I was super curious to see how well solder paste would augment a spot weld Your results look very promising! One remark that matches your observations: solder paste contains not only flux but also chemicals that remove corrosion, which is why the recommended reflow profile usually starts with a pre...
by tatus1969
Oct 29 2019 6:05am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

tomjasz wrote:
Oct 25 2019 6:42pm
My POS dead Sunnko was $250. My new KWeld will be $234.

The real question is will they perform better?
Never owned a Sunkko, but I can tell that I have quite a few customers who told me that they have dumped their Sunkko after having used kWeld 8)
by tatus1969
Oct 29 2019 6:00am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

I'd have expected the screws holding the electrode to be towards the bottom of the electrode holder not the top so they can still hold worn electrodes. That was done deliberately, to create a longer path that the picked up heat can travel before reaching the holder. I have quite a few of these in s...
by tatus1969
Oct 23 2019 3:55am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Has anybody tried welding aluminum with the KWeld? I did that for a customer to test kWeld suitability. Tested cells had alu cans - does *not* work. That precision resistor I knocked off and lost from my first super cap board is on order, but Mouser says they won't be in stock until January. https:...
by tatus1969
Oct 22 2019 5:09am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

The spot welds are the highest resistance point between the cell and the nickel or copper. I'm not convinced of that... Yes, they are tiny, but they are also very short. So I did some back-of-the-envelope calculations: spot height 0.5mm, spot diameter 2mm, shape of a cylinder, material composition ...
by tatus1969
Oct 17 2019 8:15am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: New welding metal

john61ct wrote:
Oct 16 2019 3:26pm
ossivirt wrote:If you feel like you need to. 2000 amps is the max allowed
Who regulates, in what jurisdiction?
Physics does, as well as the welder's current measurement and protection :wink:
by tatus1969
Oct 16 2019 6:41am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: New welding metal

.15mm = 50 joules .3mm = 100 joules So I'm guessing I need 30-40 joules for the .1mm alloy. But then since it is part copper and SS...who knows! I've never welded .3mm before. It takes a lot of energy to get decent welds and even then they are not as strong as the .15mm welds. 50 joules and .15mm d...
by tatus1969
Oct 15 2019 4:38am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: New welding metal

ElectricGod wrote:
Oct 14 2019 9:37pm
check out that .1mm thick alloy! Not much more resistance despite being 1/3rd as thick.
That's awesome! Curious to see how that welds.
by tatus1969
Oct 11 2019 3:58am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: KWeld modding

tore off the resistor at R31. Looking at the other board it is labeled 657 or 650,000,000 ohms or 650 meg ohms, but that seems unlikely. Murphy got you, because that's a 6k57 0.1% precision resistor, which you most likely don't have in your drawer :-) That's part of the internal voltage reference g...
by tatus1969
Oct 09 2019 10:40am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

As a side measure, something that I have assumed is that all the caps are charging to the same voltage and actually balancing. I don't really know if that's true or not. The module does balancing, but it does it in a way that it equalizes the voltages across the capacitors (within a few ten millivo...
by tatus1969
Oct 08 2019 9:41am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

flippy wrote:
Oct 08 2019 9:36am
does the thicker leads also help with the cable length performance
They help reduce resistance and increase current, but the inductance doesn't change and therefore the system's current limit. These are actually also longer, 650mm instead of the stock 400mm.
by tatus1969
Oct 08 2019 9:24am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Just wanted to share a piece of work with you that I am doing for a customer. These teflon handles will provide additional heat insulation and should allow significantly faster welding speed. The assembly also uses 6AWG leads, which should help keeping them cooler as well.
IMG_20191008_161404.jpg
IMG_20191008_161404.jpg (101.74 KiB) Viewed 296 times
by tatus1969
Oct 08 2019 4:21am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Perspective is everything... Not risk adverse: Colin Furze... https://www.youtube.com/watch?v=s4QBhNkaAk8 https://www.youtube.com/watch?v=LDM9aXVAoOw Risk adverse: Sloooooooow drivers... https://www.youtube.com/watch?v=hnml1rxiyIw Guess which one applies to me? I'm definitely of the first category....
by tatus1969
Oct 07 2019 4:46am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

I've put lots of stuff in series and they work OK. That approach would be suitable for stuff that is not potentially dangerous like ultracaps or Lipos, but in this case I have to raise the :warn: :warn: flag again and strongly discourage from doing this. Please don't treat this as an offense toward...
by tatus1969
Oct 03 2019 3:43am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

I have purchased a second super cap board so I can run them in series for more voltage. I want to mess with using my many LIPO packs as a power source, but they are all 4S or larger which isn't compatible with a single super cap board...as I demonstrated previously. My existing super cap board will...
by tatus1969
Oct 01 2019 3:57am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: K-weld super cap board experiment with over volting

WARNING: Do this at your own risk and frankly I recommend that you don't!!! WARNING: Please do not do this at all, this is very dangerous and can even lead to permanent injury! These caps can break down violently when being charged beyond their rated voltage! What can legit Maxwell caps handle? [.....
by tatus1969
Sep 17 2019 5:01am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Can you figure out what might be wrong? The voltage is absolutely okay, and if the welder makes consistent welds as well then I suspect an entirely different problem. Do you have the firmware updater so that I can send you two different firmware images for testing? I'm varying the 'short' detection...
by tatus1969
Sep 16 2019 12:33pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

@tatus1969. Perfect. Thanks for info! This is a well documented thing and there is a paper (among several) from a Chinese searcher in a university I can't remember, detailing scientifically his findings. I will post a link to it soon. Traveling overseas now with only my phone and missing my desktop...
by tatus1969
Sep 16 2019 8:18am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Question for Kweld's designer: Do you have any plans for adding a function in a future release that would switch the polarity half way through the welding cycle? As I am sure you know, DC spot welders don't form a similar nugget under the anode and the cathode for reasons we do not need to get into...
by tatus1969
Sep 10 2019 5:28am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld - "Next level" DIY battery spot welder

Can you figure out what might be wrong? The voltage is absolutely okay, and if the welder makes consistent welds as well then I suspect an entirely different problem. Do you have the firmware updater so that I can send you two different firmware images for testing? I'm varying the 'short' detection...
by tatus1969
Aug 27 2019 4:39am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld -

A right size resistor to limit current? Longer avg6 batteryleads and or smaller and worse connectors :mrgreen:. Not recomended mut if you keep them under max allowed lenghts if will loose some current.. Adding resistance in whatever way isn't recommended as it only produces more heat. Adding cable ...
by tatus1969
Aug 26 2019 7:55am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 949
Views: 106881

Re: kWeld -

Doubling capacity halves the C-rate for given current, or doubles current at the same C-rate. That's right but doesn't show the full picture. kWeld does basically short circuit the battery when pulsing, and the amount of current is directly given by Ohm's law: voltage stays constant when parallelin...