kWeld - "Next level" DIY battery spot welder

[negativ3]

Please let us know when Paypal is ready to use.

[tatus1969]

Please let us know when Paypal is ready to use.

I had them on the phone last Saturday, they told me that unlocking it for businesses is a manual process and that I will have to wait for one to two weeks  I will definitely keep you updated, and notify you immediately.

[Kjelt]

Oops did we have to wait with the pre-order? I am confused 

[Fraser]

From what I understand,

Pre order is fine if you do not mind using the 'Stripe' secure credit card payment system. The delay relates to Frank getting his PayPal approved for accepting payments via the web page.

Fraser

[Kjelt]

Ok good to hear  , problem is more that credit card transactions cost the seller more than a paypal transfer.

[tatus1969]

From what I understand,

Pre order is fine if you do not mind using the 'Stripe' secure credit card payment system. The delay relates to Frank getting his PayPal approved for accepting payments via the web page.

Fraser

Thanks for answering this for me 

Ok good to hear  , problem is more that credit card transactions cost the seller more than a paypal transfer.

That appears not to be the case here. Paypal charges more than Stripe... Anyway, they both charge something, but that is my duty 

[Kjelt]

Good to hear now I don't feel guilty 

[tatus1969]

Good to hear now I don't feel guilty 

Companies like Visa and Paypal should feel guilty, not you!

[tatus1969]

It was again exaggerated complexity that kept me from getting where I want. There is Paypal, Paypal Express, Paypal PLUS, then they tell you something about different APIs, bank account authorization, and so on. To summarize this: Paypal is now available in the shop, it was again easier/quicker than expected!

[tatus1969]

I wasn't happy with the lifetime of my regular Turnigy 3S/5Ah/50C packs. I know that my usage profile for welding with them was far from daily life duty, I think during my abuse test with the cookie can it was more or less 50% duty cycle at 1kA. I have ruined two packs until they both showed noticable swell. They are still usable, and pulse current is still at 900A, but I am aware that this literally playing with fire, and I wouldn't copying this to anyone.

Hence, I decided to order one of these, and make a test under "realistic" usage conditions for welding:

https://hobbyking.com/media/catalog/product/cache/3/image/565x414/9df78eab33525d08d6e5fb8d27136e95/1/7/175937_9210000231-0.jpg

These are rated at 130C (pulse), which is 650A (!). Let's see what they will deliver in practice.

[DBecker]

I expect that the flux is primarily excluding atmospheric gases as the weld cools, preventing discoloring.  You might compare the effect to mineral oil and brake fluid.

[maukka]

I went with a Turnigy Graphene 6000mAh 5S1P 65 battery. According to Mooch they seem to be the best performers in high current applications (low internal resistance).

[tatus1969]

I went with a Turnigy Graphene 6000mAh 5S1P 65 battery. According to Mooch they seem to be the best performers in high current applications (low internal resistance).

That is what I also ordered, but 5Ah/3S. Will be interesting to see my system running at 5S, that is still on my to do list.

[BFX]

Did you try power up your Gerät by MOT? For users which refuse buy an battery? 

[tatus1969]

Did you try power up your Gerät by MOT? For users which refuse buy an battery? 

That'll not work easily because the module expects DC, the power switch is not bidirectional. One would need to add a diode with at 1000A pulse rating at the input, but that would also require a firmware extension that synchronizes firing with the rectified waveform.

The options that I can recommend at this time are a capable enough Lipo battery [that still has to be evaluated], a good car battery, and a suitable ultra capacitor.

[tatus1969]

All the parts and tools for the new electrode system have arrived now. I will make a first complete build with video, but the first critical question is already answered: does the cable crimp work? See this picture of a cross section 

[Kjelt]

  that looks as it is supposed to be, contact me please before shipping as it now looks like this crimp connection and new electrode system are really what I would like.

[tatus1969]

that looks as it is supposed to be, contact me please before shipping as it now looks like this crimp connection and new electrode system are really what I would like.

If you like to change, or cancel and redo your order, please just give me a note. I can refund you whathever the difference is, and you don't need to worry about having to pay double shipping.

Cheers
Frank

[tatus1969]

Here are pictures from the first build of the new electrode arrangement. The clamping mechanism works very well. I have done some welds with it, and it develops less heat than the previous design. I'll keep it like that and this is (or the parts for it) is what will be delivered when ordering it from the shop.

[Fraser]

I decide that a simple hydraulic crimping tool would be useful to have in my tools collection so I have bought one this evening.
It is likely not that great for serious work but should meet my needs and those of this project. I also intend to use it as a mini hydraulic press once I have made up some flat face 'dies'.

There are two very similar looking versions on eBay. One is rated at 8T, whilst the other has a stronger head and is rated at 10T. The 8T comes with 8 dies and the 10T comes with 9 dies. I went for the 10T version.

The cost is £21.99 delivered from a UK warehouse. They are cheaper direct from China but I did not want to wait.

http://www.ebay.co.uk/itm/10-Ton-Hydraulic-Crimper-Crimping-Tool-Wire-Battery-Cable-Lug-Terminal-9-Dies-/322502047411?epid=1944118370&hash=item4b169eb6b3:g:LWEAAOSwT-FZCFV2

Fraser

[cs.dk]

Thanks for the link, Fraser.. I though hydraulic crimpers were a lot more expensive.. 
Had to buy this one; http://www.ebay.co.uk/itm/322465802286

[Fraser]

Yes I was surprised as well. I considered the 16T version but it lacked the smaller 4,6 and 8mm dies that I would find useful. If I ever need to crimp the larger sizes I will certainly buy the 16T version as well.

Fraser

[tatus1969]

I decide that a simple hydraulic crimping tool would be useful to have in my tools collection so I have bought one this evening.
It is likely not that great for serious work but should meet my needs and those of this project. I also intend to use it as a mini hydraulic press once I have made up some flat face 'dies'.

There are two very similar looking versions on eBay. One is rated at 8T, whilst the other has a stronger head and is rated at 10T. The 8T comes with 8 dies and the 10T comes with 9 dies. I went for the 10T version.

The cost is £21.99 delivered from a UK warehouse. They are cheaper direct from China but I did not want to wait.

Mine is a pure mechanical one, limited to 50qmm. It is less versatile as it has a fixed revolver style tool set, which is not milled but punched. But it has one advantage, it is quick to use.

[cs.dk]

For 4 and 6 mm i usually use DuraSeal ringterminals. Not lugs like the bigger (battery) ones. I've never seen a 8 mm2 cable. In Denmark we go from 6 mm2 to 10 mm2, that i'm aware of. Thats why i supposed i don't need em.

Mechanical ones are fine for most things, i use one at work everyday. But for a 70 mm2, you really need to push hard.

[tatus1969]

For 4 and 6 mm i usually use DuraSeal ringterminals. Not lugs like the bigger (battery) ones. I've never seen a 8 mm2 cable. In Denmark we go from 6 mm2 to 10 mm2, that i'm aware of. Thats why i supposed i don't need em.

Mechanical ones are fine for most things, i use one at work everyday. But for a 70 mm2, you really need to push hard.

We had to do 6 x 150qmm on a ship once, to supply a 500kW hydraulic power pack. That was luckily done by the shipyard, they have no problem with that 

the wire gauge that I use for the welder's electrode cable is an important part of the electrical system, also because it mainly defines the maximum pulse current level. If you choose to use cables with a larger cross section, then you'd have to pay attention to the total resistance budget, and make sure not to exceed the 2kA absolute maximum current level. Two days ago I made a(nother silly) mistake during my tests with the new electrode holder, by using a 5mm thick flat steel bar as weld material "simulator". I forgot to separate the electrodes by at least 20cm and placed them close to each other instead as I would do for a normal weld. I fired four or five times until I noticed that this was more than one second of continuous 1.2kA current flow. The battery didn't like it, and the Deans battery connector that is still there, even less. The welder has no problem with this, except that it realizes that the weld spot resistance is very very low and most of the energy goes elsewhere, which causes it to keep the current flowing until it times out or the energy was delivered at last.