Best Lithium Ion Battery Tab Spot Welder "NO Super Capacitor" DIY





Introduction: Best Lithium Ion Battery Tab Spot Welder "NO Super Capacitor" DIY

About: Its all about life hacks, tools, scientific & creativity instructables ~ electron7m


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"



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    29 Discussions

    Hi could I use 22,000uf 35v and how many would I need to make this welder?


    4 replies

    You could, but you would need arround 10 - 15 in parrallel. or you could use 30 of these

    Hi thank you for your reply. I have got 2
    capacitors each are 2.7v 500F these are super capacitors and are marked Green-cap EDLC(DB) could I use
    these and can you advise? How I could charge them and wire them? and what bulb
    would I need or do I need a bulb?




    6 months ago

    I look and compare it with this your other video:

    Which is differences?

    Which is better?

    Which is cheapest?

    The peak power delivered by your method will be influenced by the gauge and length of the wires connecting the capacitors to the copper rods. Shorter or thicker wires will produce a higher peak power and thinner or longer wires will produce a lower peak power. The peak power has to be enough to melt the weld area without blasting away too much metal.

    Anybody making a setup like this would do well to copy faithfully. Adjustments can be made after you have evaluated the performance of the rig.

    Could you use a 12 volt power supply (from a laptop) instead of a battery? How many amps would it need to supply?

    2 replies

    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 :)

    Charging large capacitors is difficult for a power supply. At the beginning of charge when the cap is not charged the power supply sees a short circuit. At the end of charge the supply sees an open circuit.

    Most switch mode supplies don't like either conditions. The protect themselves by shutting down in the case of a short circuit. They don't regulate when they see an open circuit and may put out an unexpectedly high output Voltage. You might be able to get it to work by having a series current limiting circuit (resistor) and a minimum load resistor.


    11 months ago

    Hello there,

    Good and simple, will do me.

    What is the wattage of the bulb?


    The value you give: "1,10,000 micro Farad capacitor" is completely meaningless.

    Please would you check and correct this value ? Many thanks.

    3 replies

    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.

    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.


    1 year ago

    where else can you get them beside a large DC motor?

    1 reply

    go to an electronics shop and ask them for high capacitance capacitors.. connect the accordingly to achieve the required voltage and capacitance :)

    I think the confusion is that you wrote that the total is "3,30,000" it should be "330,000" uf. "Three hundred, thirty thousand uf" total. Do you know where you got these for $1 each?

    1 reply

    I got it from a scrap dealer who said that he got it from Large DC motors.

    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.

    I guess the total capacity of this setup is 330 F!