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Hi!

This instructable is about making a spot welder that makes better battery tab welds without spending too much money on super capacitors cause i have found that the super capacitor spot welds are not as great as the method that i am teaching you now.

•This method is simpler.

•it's more reliable.

the capacitors used here charge faster.

•here the spot welding operation is performed within safe voltage range of 12 to 14 volts.

Just follow the step by step procedure or go through the video :)

" Youtube channel link"

Step 1: Capacitor Bank:

You will need a minimum of 2 such capacitors to be connected in parallel.

Here I have used 3 identical 110,000 micro Farad capacitor so the total is 330,000 micro Farad capacitance so the minimum capacitors you will use will be 2 and the maximum will be around 4 with the voltage range of 14 and above.

"youtube channel link"

Step 2: Connecting the Capacitors Together:

•Stick the capacitors to each other with the silicon gun and rubber bands as shown in the picture.

•Use 2 thick wires.Connect the first wire to the positive of all the capacitors and then take the other wire and connect it to all the negative terminals of the capacitor."youtube channel link"

Step 3: Battery / 12V Bike Bulb / Nickel Strip / Copper Conductors:

  • Use any charged & working 12V battery.I have used a 12V 7Ah UPS battery.
  • use a 12 volt motor bike bulb.
  • get the lithium ion battery to which you want to do spot welding.
  • get the Nickel alloy strips to weld the battery tabs.
  • get 2 thick copper conductors and you can get these conductors from the COPPER shaded ring induction motor.

Step 4: Connections:

There should be 4 wires coming out of the capacitor Bank.One set of positive and negative will be connected to the battery with a series 12V bulb connected to it as shown.

Copper rods will be connected to the other two wires for doing spot welding to the batteries

The series bulb acts as a resistor here thereby limiting the current flowing from the battery to the capacitors and to the copper rods because when the spot welding occurs, then there is a short circuit and that short circuit creates a real high current that will discharge the battery faster ,depreciate its overall life and also destroy the Nickel alloy strip.

The bulb also acts as an indicator that the spot welding has been completed."youtube channel link"

Step 5: Protection:

Wear eye protection glasses and gloves as there will be Sparks :)

"youtube channel link"

Step 6: Spot Welding:

Cut a small portion of the nickel alloy strip and keep it on the battery terminal (the battery to which you are going to do spot welding). Touch the first copper rod to the battery without touching the nickel and the second to the nickel alloy strip.This will create a short circuit and the hot spot will be b/w the battery and the strip and thus melting them and sticking them together. :)

"youtube channel link"

Step 7: Spot Welding Completes:

So that was all guys.Thank you for your time :)

"youtube channel link"

<p>The value you give: &quot;1,10,000 micro Farad capacitor&quot; is completely meaningless.</p><p>Please would you check and correct this value ? Many thanks.</p>
Its correct.It says that each of the 3 capacitors have a value of 1,10,000uf making a total of 3,30,000uf.I don't see any mistake.<br>
<p>The mistake is the extra comma. The value is 110,000uF (0.11F). The extra comma makes people think it's 1.1F, which is incorrect.</p>
Ohhh!
<p>where else can you get them beside a large DC motor?</p>
<p>go to an electronics shop and ask them for high capacitance capacitors.. connect the accordingly to achieve the required voltage and capacitance :)</p>
<p>Could you use a 12 volt power supply (from a laptop) instead of a battery? How many amps would it need to supply?</p>
<p>yes you can... amps is not an issue.It will work with a 0.5A power supply as well as 10A power supply.The only thing thats effected is charging time of capacitors :)</p>
<p>I think the confusion is that you wrote that the total is &quot;3,30,000&quot; it should be &quot;330,000&quot; uf. &quot;Three hundred, thirty thousand uf&quot; total. Do you know where you got these for $1 each?</p>
<p>I got it from a scrap dealer who said that he got it from Large DC motors.</p><p>Its not that big a deal.If you can't get them then buy 5 cheap 1.5F supercaps and connect them in series to get exactly same value.</p>
<p>I guess the total capacity of this setup is 330 F!</p>
No its 0.33F .330F would be too much..
<p>I've looked for these size capacitors, and they are VERY expensive. Do you know where one might find some discarded or used?</p>
I got these for 1$ each.These are connected in parallel with large DC machines.. U need not use the exact.Just make a capacitor bank of 15V &amp; ~3,33,000uF capacitance.<br>
<p>Very well. simple and easy to build.</p>
<p>Thanks Saeed Nazarian :)</p>
Very nice. Simple and genious. Keep up the good work. Thank you.
brajomobil Thanks a lot :)
<p>Can't you disconnect the battery (with a switch) once the capacitors are charged? That way you don't have to worry about any huge draws on the battery during the weld.</p>
<p>yes but this way everything is much better and also there is not more than 3A drawing during peak capacitor charging or during short circuit while spot welding because of the current limiting bulb :) If the bulb had not been there ,i would have certainly used a switch :) </p>

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