kWeld - "Next level" DIY battery spot welder

Batteries, Chargers, and Battery Management Systems.
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Re: kWeld - "Next level" DIY battery spot welder

Post by macribs » Aug 02, 2017 5:33 pm

Yeah I kind of had to edit that, last week of summer vacation so tonight I was committed to finish off a 6 pack of homebrew and a few of those tiny bottles of Underberg. **Just to be on the safe side of expiration date**. So I figured I tone things down a notch. Don't drink and type or something :wink:

Drunk and happy I edited it back in again. Trink and dype is so much fun. Cheers.

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

Post by liveforphysics » Aug 02, 2017 11:54 pm

Nice job in your measurement. Tough little cells.
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Re: kWeld - "Next level" DIY battery spot welder

Post by tatus1969 » Aug 04, 2017 1:08 pm

liveforphysics wrote:Nice job in your measurement. Tough little cells.
Thanks!
liveforphysics wrote:My bicycle completes the standing quarter mile in 11.502seconds at 110.56mph.
What the f...?
macribs wrote:**Just to be on the safe side of expiration date**
Everthing that has < 1yr left should be taken care of, one never knows...
macribs wrote:Trink and dype is so much fun. Cheers.
I know don't drink and drive, and maybe don't drink and type, but what is that? 8)
Last edited by tatus1969 on Aug 04, 2017 1:12 pm, edited 1 time in total.
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Re: kWeld - "Next level" DIY battery spot welder

Post by spinningmagnets » Aug 07, 2017 7:10 pm

liveforphysics wrote:
My bicycle completes the standing quarter mile in 11.502seconds at 110.56mph.

What the f...?
https://www.youtube.com/watch?v=PW7M-vpFUkI

https://www.youtube.com/watch?v=Sk_bmSRog-c

https://www.youtube.com/watch?v=kjLUAkWoOEE

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Re: low cost DIY battery spot welder

Post by redilast » Aug 07, 2017 10:15 pm

tatus1969 wrote:Just yesterday I have ordered 0.1mm copper foil and some of these, these are 0.3mm nickel.

Image
Where did you get those from? eBay? I see the URL mentions eBay but I've not been able to find them.

These types of tabs are commonly used for commercial pack building. The H tabs as you probably know put more energy through the cell and less through the tab making stronger welds. The other benefit is less tab discoloration and less electrode sticking. The dimples also aid in focusing the energy well.

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

Post by tatus1969 » Aug 08, 2017 7:30 am

That video is just the best 8)
redilast wrote:
tatus1969 wrote:Where did you get those from? eBay? I see the URL mentions eBay but I've not been able to find them.
The ebay link is this one:
http://www.ebay.de/itm/10-St%C3%BCck-Ho ... 2749.l2649

or this
http://www.ebay.de/itm/10-Stuck-Hochstr ... SwMgdXzHZQ

I've tried to translate the German search term, without success :?
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Re: kWeld - "Next level" DIY battery spot welder

Post by redilast » Aug 08, 2017 5:06 pm

Thanks for the info. After using google translate, it appears those tabs are not pure nickel, but nickel plated steel.

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

Post by parabellum » Aug 08, 2017 5:42 pm

redilast wrote:After using google translate, it appears those tabs are not pure nickel, but nickel plated steel
Can you post the text that make you think that, in German. I did not found any statement about material used.

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

Post by redilast » Aug 08, 2017 11:01 pm

parabellum wrote:
redilast wrote:After using google translate, it appears those tabs are not pure nickel, but nickel plated steel
Can you post the text that make you think that, in German. I did not found any statement about material used.
"vernickeltes Kaltband (Hilumin)"

Google translates to:

"Nickel plated cold strip (Hilumin)"

And then when I search for Hilumin, I get this: https://www.tatasteeleurope.com/en/prod ... ed/hilumin

Hilumin appears to be a trademark name for "electro nickel-planed diffusion annealed steel strip for battery applications."

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

Post by parabellum » Aug 08, 2017 11:29 pm

redilast wrote:"vernickeltes Kaltband (Hilumin)"
Thanks, now I see, it is in Akku-jack description link page. :oops:

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

Post by Ohbse » Aug 09, 2017 12:10 am

I like your design very much, really enjoyed your videos.

I went to pre-order and unfortunately all sold out? If possible I would like to pre-order for the next batch :)

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

Post by tatus1969 » Aug 09, 2017 12:52 am

Ohbse wrote:I like your design very much, really enjoyed your videos.

I went to pre-order and unfortunately all sold out? If possible I would like to pre-order for the next batch :)
Thanks :D I am going to concentrate on timely shipment now, allow for some time (maybe 2-4 weeks) to have customers test them and report me/us back how they like them and what possibly needs to be improved, and then start the next batch. That is the time where I will be able to offer pre-orders again. The second one will definitely be larger, maybe 100 kits, so don't worry that you won't get one :wink:

parabellum wrote:
redilast wrote:"vernickeltes Kaltband (Hilumin)"
Thanks, now I see, it is in Akku-jack description link page. :oops:
I can confirm that, and I also have tested this here: it is nickel plated steel. This motivated me to test all other stuff that I have here: all the same. Also the professionally manufactured battery packs that I have tortured in my videos are apparently made from Hilumin: nickel plated steel. That rises the question for me: is this the standard way? But what about high current packs, steel has at least 10x worse conductivity than nickel.

I will order some pure nickel strips and see how well the welder can handle these.
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Re: kWeld - "Next level" DIY battery spot welder

Post by tatus1969 » Aug 09, 2017 5:57 am

tatus1969 wrote:I will order some pure nickel strips and see how well the welder can handle these.
Hmmm, it seems difficulty to find a reliable source for pure nickel strips. Everything turns out to be nickel plated steel so far. Can anyone point me in a direction where to look? I only need a small length for testing purposes at the beginning.
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Re: kWeld - "Next level" DIY battery spot welder

Post by macribs » Aug 09, 2017 8:30 am

Are you looking for the regular 100% nickel strips or the indented H type strips you posted about earlier?
In some of the battery threads there are links to reliable sources on aliexpress etc. If you search forum for saltwater testing nickel strips / corrosion testing nickel strips you will find them. Them threads didn't show up in my bookmarks so can't help with a link right now.

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

Post by hemo » Aug 09, 2017 4:34 pm

Acquired these recently and they passed the scratch and saline test and are genuine Ni.

https://www.aliexpress.com/item/100pcs- ... 0.0.oVlg5N

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

Post by tatus1969 » Aug 10, 2017 12:45 am

thanks for your tips. I found these at ebay (160974484305) and ordered some. They are 0.2mm. The seller confirmed that they are pure nickel.

I am busy with the next product video, and realized that the new probe design is now thermally the limiting factor. Too bad as it is the only part that you need to hold. Therefore I started a third iteration, the idea is to use 6mm copper rod and thread that down to M5. The holder will be threaded as well, which means that you then can screw in the electrodes. That should significantly reduce ohmic losses there. Parts ordered, I'll keep you updated.
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Re: kWeld - "Next level" DIY battery spot welder

Post by Ohbse » Aug 10, 2017 3:49 pm

tatus1969 wrote:I am busy with the next product video, and realized that the new probe design is now thermally the limiting factor. Too bad as it is the only part that you need to hold. Therefore I started a third iteration, the idea is to use 6mm copper rod and thread that down to M5. The holder will be threaded as well, which means that you then can screw in the electrodes. That should significantly reduce ohmic losses there. Parts ordered, I'll keep you updated.
Great idea. Unfortunately large currents through threads tend to do funny things and can frequent become very difficult indeed to undo. Perhaps look at a tapered pipe type thread? These allow for more positive thread engagement (and thus low resistance) and near guarantee of removal. Might prove to be a non issue in practice :)

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

Post by timmy66 » Aug 11, 2017 3:19 am

Hi Tatus - rather than the small hobbyking/LiPo packs, am curious what you think the suitability would be with these (now) very common "jump starter" packs that say rated up to 600 A at 12 V ?

For instance,

http://www.amazon.com/Beatit-18000mAh-P ... ref=sr_1_1?

Seems would be more versatile for other uses, more total energy than the ones you've tested, etc.

Since you're measuring the total energy observed, hopping between sources seems much easier with predictable outcomes.

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

Post by Alan B » Aug 11, 2017 9:52 am

Starter packs are not a good ebike traction battery answer, and their ratings are typically incorrect (they rate the amp hours as though they were in parallel but are actually in series, so divide by 3).

Edit - forgot which thread I was in, for welding these might be suitable.

They generally contain small 3S lipos. They are made for occasional high current discharges and don't last too long if run down frequently, at least that was the case with the cheap Walmart Everstarts. Higher quality units might hold up better. Probably not worth testing. (I would add that the starter lipos are not likely to be nearly as good as the ones being tested here. I'd guess that several of the starter packs in parallel might work, but a single one is unlikely to be good enough to last very long. Stick with what has been tested already.)

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

Post by tatus1969 » Aug 11, 2017 4:16 pm

I doubt that these packs are suitable, engine cranking requires maybe 100-200A, which is way below what the welder needs. Overstressing Lipos can be very dangerous, and the swell of my initially used regular Turnigy's directly disqualified them.

I'll keep concentrating on the Turnigy nanotech 3S 5Ah 130C. I stress tested it two days ago while shooting video, and then accidentially deleted the entire footage, 30Gb... :?

What I can already say that a complete discharge cycle resulted in approx 900 pulses of 30J into 1mOhm, and an accumulated pulse time of 15 seconds, at a current of 1400A average. And most importantly, absolutely no visible battery swell.

That is enough for me to say that I can recommend them for my welder. The only limiting factor is that they have only AWG10 wires, which limits pulse repetition rate. The battery temperature needs to be checked as well, I could not run my rapid firing test in one go, there were quite a few cooling breaks.
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Re: kWeld - "Next level" DIY battery spot welder

Post by spinningmagnets » Aug 11, 2017 5:21 pm

The only limiting factor is that they have only AWG10 wire
For those who don't have a local supply, Hobby King now has 8-AWG / 8-ga (50% more copper mass, 30% less resistance?)

https://hobbyking.com/en_us/hardware-ac ... tore=en_us

______area of cross-section__diameter of copper__peak amps
10-Ga___5.26/mm-sq____________2.59mm________120A
08-Ga___8.37/mm-sq____________3.26mm________180A

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

Post by parabellum » Aug 11, 2017 10:37 pm

spinningmagnets wrote: Hobby King now has 8-AWG / 8-ga (50% more copper mass, 30% less resistance?)
Yes, I always waited for weeks to month from Hong Kong, but now they have it in US. I ordered 10 meters from US warehouse last time and got 10x 1M individually packaged 8AWG wire peaces. :D

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

Post by tatus1969 » Aug 13, 2017 6:06 am

parabellum wrote:
spinningmagnets wrote: Hobby King now has 8-AWG / 8-ga (50% more copper mass, 30% less resistance?)
Yes, I always waited for weeks to month from Hong Kong, but now they have it in US. I ordered 10 meters from US warehouse last time and got 10x 1M individually packaged 8AWG wire peaces. :D
That's great, just as you have certainly wished it :wink: Just imagine that you'd to cut it into pieces by yourself, what a hassle :P
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Re: kWeld - "Next level" DIY battery spot welder

Post by tatus1969 » Aug 13, 2017 7:06 am

The manufacturing of the pre-ordered kWeld electronics is running well, and I expect to have received everything by end of next week. I will start testing and programming them right after arrival and expect to be able to ship in week 34. If you have pre-ordered one, then I hope that you like working with the system as much as I do, and please give me your honest feedback.

In the meantime, there have been a few more additions and improvements. I am showing them on Youtube:

https://youtu.be/rQnODV4VQjU

- the system firmware has been extended by a bootloader that allows firmware updates via a simple serial connection. All you need is a terminal program that supports YMODEM file transfers, and an adapter that is available in the shop: https://www.kicksurfer.de/index.php/pro ... date-tool/
kweld-programmer-small.jpg
firmware update accessory
kweld-programmer-small.jpg (21.87 KiB) Viewed 801 times
- a first sample of a 3D printed housing has arrived, and I am currently testing it. I plan to make it available in the shop, and also to provide the 3D data for free to enable you printing your own.
IMG_20170813_123412.jpg
3D printed case
IMG_20170813_123412.jpg (70.85 KiB) Viewed 801 times
- I have tested a new type of Lipo battery for use with the welder: Turnigy nano-tech 3S 5Ah 130C (https://hobbyking.com/en_us/turnigy-nan ... -pack.html). This is the first battery that has survived more than one hour of continuous torture testing without any measurable swell or other damage. This is so far the only Lipo that I can definitely recommend to you. You can download the torture test results here: https://www.kicksurfer.de/wp-content/up ... e-test.zip

- the electrode system needed to go through a third iteration. The battery torture test showed that the previous system had a too high ohmic resistance and was heating up too quickly. As a side effect, I could again significantly reduce the involved machining effort. The new system only requires crimping the cable to a brass tube, thread-tapping tube and copper electrode, and heat shrinking an isolation. This also makes electrode replacement easier than ever before.
IMG_20170812_220553.jpg
new probe design
IMG_20170812_220553.jpg (45.97 KiB) Viewed 801 times
As the previous electrode design did not meet my quality requirements, I will inform all pre-order customers that they will receive the new design instead at no additional cost.
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Re: kWeld - "Next level" DIY battery spot welder

Post by tomjasz » Aug 14, 2017 2:21 pm

Great work,

I'm looking forward to the next release.

I really have no interest in owning Lipo again. What are the options?

Also, since I have 2 other welders and three sets of weld electrodes and wiring, can the next kit be purchased without selecting "cable / electrode holder / electrodes completion grade"?


Thanks!

Thanks!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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