Author Topic: kWeld - "Next level" DIY battery spot welder  (Read 323577 times)

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Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #575 on: June 28, 2018, 09:30:22 am »
Really impressive project, I've just ordered a kWeld myself.
Thanks :-)

One question though, do you have any plans to open-source the firmware ? I mainly ask because I hate transflective LCDs and would like to switch it out with a nice OLED module.
I don't like the display either, the decision for that back then was simplicity: been out there for decades, zero lines of code to implement and use.

Sorry, at the moment, I want to keep the source code closed to keep Chinese copiers away for as long as possible. But I can share the circuit if that helps.
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Offline yngndrw

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #576 on: June 28, 2018, 10:08:43 am »
Fully appreciate the issue with cheap clones, they ruin things for everyone.

I don't think the circuit alone would help (Just need an SPI or I2C port really - From your earlier schematic it looks LCD RS, RW and E are all members of SPI port 2 which is ideal) as the OLED displays tend to be full graphical modules rather than having a text-based controller, so major code changes would be required.

I was looking at using something like this: (It's 4 wire SPI, but chip select isn't needed - There are some cheaper monochrome versions)
https://www.adafruit.com/product/1431
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #577 on: June 28, 2018, 08:18:40 pm »
From your earlier schematic it looks LCD RS, RW and E are all members of SPI port 2 which is ideal)
Did a quick check - bad luck, none of the SPI lines are available (current design uses STM32F103C6T6A).
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Offline yngndrw

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #578 on: June 28, 2018, 10:17:36 pm »
Oh sorry, I must have been looking at the wrong datasheet.

That's a shame. Are there any I2C lines available ? I believe it can be either PB6/7 or PB8/9 for that microcontroller ?

If so, there are a couple of monochrome OLED displays which support I2C:
https://www.adafruit.com/product/931
https://www.adafruit.com/product/938

I've used the smaller one before and it's a really nice display, but the bigger one would allow a larger font and would therefore be more readable. I2C is a little slow for graphical displays, but I have had some success increasing the clock rate with these.

I guess failing this, it would be possible to output the current status (I.e. Everything that's displayed on the LCD and more) via the firmware update serial port and display that with a second microcontroller who's responsibility is just to drive the graphical display - That would also enable upgrades for existing customers.
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #579 on: June 29, 2018, 08:48:49 am »
That's a shame. Are there any I2C lines available ? I believe it can be either PB6/7 or PB8/9 for that microcontroller ?
Interestingly, PB6/7 is available at the red MicroMatch connector along with +3V3 / GND :-)
But you can always bit-bang SPI, that'll still be faster than I2C. A side remark: I don't want to give you false hopes of a firmware change. I have several other projects on my desk, and can't justify spending time on a working product like this.

I guess failing this, it would be possible to output the current status (I.e. Everything that's displayed on the LCD and more) via the firmware update serial port and display that with a second microcontroller who's responsibility is just to drive the graphical display - That would also enable upgrades for existing customers.
That would be a lot of work, because doing it right would mean to present control to the full functionality on this interface.
« Last Edit: June 30, 2018, 09:19:54 am by tatus1969 »
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Offline yngndrw

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #580 on: June 29, 2018, 09:29:54 am »
Which option, the first ?

Well assuming you're still using the Newhaven NHD-0108HZ-FSW-GBW display which uses the ST7066U controller, you have to emulate 8 characters and 4 extra segments. There are 11 instructions to implement and two blocks of memory. (DDRAM and CGRAM - 80 bytes and 64 bytes respectively) Assuming that you're not using the 4 extra segments or any of the custom character stuff, this can be simplified substantially.

Having said that, the second option with a second microcontroller which displays data from the firmware update serial port seems like a better option to me, as it allows for the new UI to better match the capabilities of the graphical display and outputting data via serial could also be useful for other applications like logging on a computer.

Datasheets I've been working from:
https://www.newhavendisplay.com/specs/NHD-0108HZ-FSW-GBW.pdf
https://www.newhavendisplay.com/specs/NHD-0108HZ-FSW-GBW.pdf
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #581 on: June 30, 2018, 09:25:28 am »
Which option, the first ?
The second. To add a graphic LCD and then just copy the information (8 characters of text) onto that would not make much sense in my opinion. I would want to actually use the bigger screen area to display more information, make the menu more intutitive, and others.

Well assuming you're still using the Newhaven NHD-0108HZ-FSW-GBW display [...] Assuming that you're not using the 4 extra segments or any of the custom character stuff, this can be simplified substantially.
Yes [...] no :-)
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Offline yngndrw

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #582 on: June 30, 2018, 03:40:13 pm »
Sorry I didn't see your edit as I was writing my response.

If the hardware I2C port is available then that is the best option, far less impact on any existing timing code that you have as well compared to bitbanging. I've used these displays with I2C at 1Mbit/sec in the past then they performed fine, even when doing high frame-rate animation.

Fully appreciate the queue of existing work you have, it was why I first asked about any plans to open-source the firmware. At least now I know that suitable pins are already available on the current hardware, so it's at least possible.
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #583 on: July 14, 2018, 06:31:30 pm »
I just got the message from my cable assembly firm yesterday, that they will be delivering early next week. Here are a few pictures from their work. This is what customers having ordered after April will receive. You can notice the upgraded electrode system, which was partly because of the electrode system crimping problems that the previous version showed.





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Offline kulla

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #584 on: July 28, 2018, 09:17:43 am »
Got mine yesterday, got to play with it already  >:D

I'm using 12V car battery for it, works like a charm.
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #585 on: July 29, 2018, 08:16:10 am »
Just saw that Dave has been opening his that I had sent him to his mailbag :-)
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Online tautech

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #586 on: July 30, 2018, 09:56:54 am »
Just saw that Dave has been opening his that I had sent him to his mailbag :-)
Seems he was most impressed.  :)

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Offline anishkgt

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #587 on: July 30, 2018, 10:10:08 am »
Beginner here - I have a big question that I hope you all would be able to help me with:

I'm planning to weld up some 18650 cells for an e-bike I'll be building and I'm thinking of purchasing the kWeld to do the job for the following reasons:

- Quality and flexibility of the kWeld system
- 120V battery spot welders like the ones from Sunkko require at least a 40-amp circuit breaker; common US homes have a 15-amp circuit breaker for the 120V outlets - this would not work for me

What are my easiest (and perhaps also affordable) options for powering the kWeld system?

- I don't have any high-powered batteries laying around so it would seem wasteful if I get a high-C RC LiPo or car battery pack and charger just for the kWeld system
- It seems the kCap requires a high-amp power supply for charging; although I have a few sub 500w ATX PSUs and 3-amp lab power supplies laying around they don't seem to be suited for the job

Apologies for my lack of knowledge on this matter. Any help will be highly appreciated!
There are quite a few reliable  replacement boards on eBay for those sunkko spot welders. I sell one of them as well. Fusing wouldn’t be a problem either. After 100s of Welds mine seem to be holding up. Here it is https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F282825618948


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Offline Cannikin

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #588 on: August 07, 2018, 08:50:32 pm »
Hey guys, I just ordered a kWeld myself! I'm looking to CNC the case based on the DXF file from the site. I've converted the DXF to SVG so that I can then convert it into gcode for my CNC machine. However, after the conversion, the parts are tiny—the base of the case is about 1" square!

Can someone who has either the case itself, or the kWeld, give me some measurements so I know how to scale this thing? If you could give me the exact length/width of the case base, or the center-to-center distance between the mounting holes in the kWeld itself, that would let me scale this thing to the proper size (see attached image). (I'm assuming that the mounting holes on the kWeld line up with the 4 holes in the base of the case, if not please correct me!)

Thanks for any help!

 

Offline smgvbest

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #589 on: August 08, 2018, 08:20:52 am »
This happens allot.  scale it for inch to mm or mm to inch(i forget which)   should do the trick
The DFX is in mm, 
A=94.8mm
B=104.1mm



Edit: Fixed a dyslexic moment there
« Last Edit: August 08, 2018, 08:23:17 am by smgvbest »
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Offline Cannikin

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #590 on: August 08, 2018, 05:00:39 pm »
This happens allot.  scale it for inch to mm or mm to inch(i forget which)   should do the trick
The DFX is in mm, 
A=94.8mm
B=104.1mm

Thank you very much!
 

Offline rx8pilot

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #591 on: August 08, 2018, 05:44:17 pm »
I want to order one of these. There are are few toys on my wish list that need to come first, but this looks like a pretty cool way to catch something on fire.  :-+
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Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #592 on: August 08, 2018, 09:16:13 pm »
I want to order one of these. There are are few toys on my wish list that need to come first, but this looks like a pretty cool way to catch something on fire.  :-+
I've finally managed create "permanent" stock --> https://www.keenlab.de/index.php/product-category/kspot-welder-kit/
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Offline netmonk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #593 on: August 25, 2018, 09:42:51 am »
Hello,
May be a stupid question, why not use XT60 input connector ? most of lipo are coming with such interface.
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #594 on: August 25, 2018, 11:48:01 am »
Hello,
May be a stupid question, why not use XT60 input connector ? most of lipo are coming with such interface.
That is because the welder draws 1400A from the battery  8) Only short pulses, but every micro ohm ESR counts.
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Offline netmonk

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #595 on: August 25, 2018, 12:28:38 pm »
i just ordered one, are input cables included in the full set ?

EDIT, i just saw that input connector xt150 are not included in the full set. can i modify my order to add them and have them soldered ?
« Last Edit: August 25, 2018, 12:30:25 pm by netmonk »
 

Offline carracing111

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #596 on: August 26, 2018, 12:35:04 am »
Hi

First of all, I want to say that Kweld together with the Kcap capacitors pack is working really well! But I am currently feeding the capacitors with 20A and I would like to improve it.

I wanted to ask you when the step down controller card for the HP DPS-800GB power supply will be for sale.
As I think it will not be available in the short term I have ordered 4 step down modules (300W 20A) like these:

https://www.ebay.de/itm/DC-300W-20A-CC-CV-Constant-Current-Adjustable-Step-Down-Converter-Voltage-Buck/263289147724?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

My idea is to connect them in parallel next to the HP power supply to power the KCap capacitors to 8.1V and 80A

it will work ? Should I add diodes? In this case, could you recommend me some?

Thank you very much
« Last Edit: August 26, 2018, 04:22:34 am by carracing111 »
 

Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #597 on: August 26, 2018, 11:17:10 am »
EDIT, i just saw that input connector xt150 are not included in the full set. can i modify my order to add them and have them soldered ?
Please just make another order and select "side order" shipping option, I'll then combine them.
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Offline tatus1969Topic starter

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #598 on: August 26, 2018, 11:23:47 am »
I wanted to ask you when the step down controller card for the HP DPS-800GB power supply will be for sale.
As I think it will not be available in the short term
It's a pity but I'm afraid that is on the "long bench" as we say in Germany. I first have to push the design projects through that my customers are waiting for. I'm very sorry for that, especially because I have a working and tested design that just needs a "bodge wire fixing" redesign step.

I have ordered 4 step down modules (300W 20A) like these:

https://www.ebay.de/itm/DC-300W-20A-CC-CV-Constant-Current-Adjustable-Step-Down-Converter-Voltage-Buck/263289147724?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

My idea is to connect them in parallel next to the HP power supply to power the KCap capacitors to 8.1V and 80A

it will work ? Should I add diodes? In this case, could you recommend me some?

Thank you very much
As they have output current regulation, they can be paralleled my design. I have no doubts that this will work.
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Offline djgrazzy

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Re: kWeld - "Next level" DIY battery spot welder
« Reply #599 on: September 15, 2018, 08:52:09 am »
If anyone is interested I made a little mount for the step down buck converters a few people are using. I can/will share the files to thingiverse as soon as i also have a base to join two of these together (I'm will using 4 of them)
 


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