Can you weld with a car battery?

Welding with car batteries is dangerous and should only be attempted in an emergency, and again batteries should be covered to reduce injuries you may sustain from hydrogen gas build-up in the battery and explosion.

Also, note that batteries connected in series increase the amperage provided by the batteries (a higher voltage is required to support the arc). If one battery produces 12 volts, two connected in series will produce 24 volts, three connected in series will produce 36 volts, and so on. The point is that a lot of power will flow through a series of connected batteries.

And finally, remember that welding hazards such as heat, sparks, eye damage from ultraviolet light, and inhalation of hazardous gases and particles are also normally anticipated.

How To Create An Arc Welder With Three Automobile Batteries

First, you need three batteries. A single battery will not be enough. Three batteries provide 36 volts of power, enough amperage to allow arc welding. Batteries must be connected in series (positive pole of one battery to negative pole of another battery) to produce the amperage needed to start and sustain the arc. To connect batteries in series, place the batteries from end to end and connect the positive end of one battery to the negative end of the next battery. For example, connect the positive pole of battery 1 to the negative pole of battery 2, then connect the positive pole of battery 2 to the negative pole of battery 3, and so on.

The last free positive terminal will connect to the metal object we are working on. This becomes the “ground terminal .”Just connect one end of a pair of battery cables to the positive pole of the last battery and the other end of the battery cable to the piece of metal you are working on.

Next, you need to connect the electrode to the battery cable (do not connect the battery cable to the battery yet). Make use of a quarter as an electrode in a pinch; it’s much easier to use a regular welding rod (easier to work with, produces better welds, and will live long). If you choose a welding rod, you may need to use pliers to pry the battery cable prongs inward to create a gap in which to hold the welding rod securely in place. Be sure that the welding rod (or quarter) is firmly fixed in the clip and that there is as much contact surface as possible between the battery cable clamp and the electrode. Securely tying a rubber strap, such as from a bicycle inner tube or other elastic material, around the clamp can provide more pressure to hold the electrode firmly in place. Similarly, clamps or a similar locking tool can be used to keep the clamp tight around the electrode (but they tend to get in the way).

Finally, to complete the connection, take the free end of the battery cable that holds the electrode and connect it to the last free pole left on the battery (which must be negative). Once plugged in, the soldering iron is now “hot,” so be careful what you touch and where you leave it.

At this point, you will probably want to cover the batteries with some sort of protective cover (lid, solder blanket, plywood sheets, etc.) to prevent sparks from igniting the batteries, as well as to provide at least some protection if the batteries were to explode. You will also require to make sure you are wearing welding gloves, a welding mask, and non-flammable clothing – the typical equipment you would wear in any welding job.


Since welding with car batteries is not as controlled as with an actual commercial welding machine, problems are bound to arise, some of which can be overcome with a little practice. For example, it is impossible to control amperage with a car battery, so if the welding rods are too thin, they will basically evaporate. The solution is to use a thicker rod or tie two rods together with bale twine.

Sometimes the electrode gets stuck in the work area. In this case, the circuit is complete, and no arc is launched. The rod will get hot and will probably catch fire. Simply break the circuit by releasing the electrode from the clamp. Once the stuck rod has cooled, you can remove it with pliers or a hammer.

If things seem to work, create an arc and then create a pool of molten metal. Push the rod in a little to fill the weld pool, move them slightly forward (half the diameter of the weld pool), and repeat. Imagine creating a red hot stack of overlapping dimes. This will produce the most “beautiful” and effective weld.

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