Can You Weld With A Car Battery: How To Do It Safely

Last Updated on September 15, 2020 by Gary Hargrave

Any conformist in the welding industry would consider welding with a car battery a crazy idea. But for those who have been in trouble in the middle of the road and had a welder in the car trunk but no easy access to a regular power source, the idea may not be impractical after all.

You can think of a car battery to power your welder, but you need three of them each having 12 volts and placed end to end. Keep the positive end of one particular battery connected with the negative end of another. Remember using safety devices and clothing.

First off, I’ll discuss the worst things about the endeavor. Then, I’ll discuss how you can do it without endangering yourself or the property around you. Let’s begin.

Can You Weld With A Car Battery

Welding with an Automobile Battery and Safety Concerns

I am not exactly someone whom you would like to call a Good Samaritan, but I can’t let you go ahead without knowing the dangers that might befall you while trying this technique to power your welding equipment.

First off, you may not have seen anyone do this kind of job, and chances are that you’re going to take steps depending on things learned from different internet sources. So as a first timer, you may not be careful enough to avoid attaching your jumper cables with reversed polarity.

Having sulfuric acid, the car batteries become extremely likely to emit hydrogen gas while the cable terminals get sparked. All on a sudden, an explosion might occur leaving you amid the unspeakable dangers. I’ve heard people got blinded by such accidents.

But that is not all. Without the regular welding safety measures, you remain vulnerable to skin burn, eye damage, and respiratory problems from the arc. Another mistake that beginners usually make is positioning the arc real close to the car batteries.

Steps to Weld with Car Batteries

Since you are interested in knowing if this particular idea can be turned into reality, I think I shouldn’t waste more of your time on awareness. Start by collecting the things you’ll use.

Required Tools

Doing something that you haven’t done before is an exciting proposition. For this to be undertaken as efficiently and safely as possible, you want the required equipment and tools in the trunk of your car.

  • 3 Car Batteries
  • Quarters
  • Battery Cables

You might already have a question why I’ve mentioned three batteries instead of one. Well, a single battery doesn’t provide the juice to create an arc that melts metals. Each battery provides 12 volts making itself insufficient to create an arc between the rod tip and the workpiece. Three or four batteries provide 36 to 48 volts of output which is adequate.

Connecting the Batteries

Wire the batteries in series making sure that the positive pole of any of the batteries is attached to the negative pole of another battery. This setup should suffice for creating and sustaining an arc. Now, the question is how you can wire more than one batteries.

Take one of the batteries and identify its positive terminal. Take another battery and identify its negative terminal. Now, keep the positive terminal of the first one after the negative terminal of the second one. Maintain the same position for the second and third batteries.

With these connections, you’ll have the positive terminal of the third battery free. Connect that terminal to the object you want to work on. You got the “ground clamp”. You need to clamp just one end of the two cables to that positive pole of your third battery with another end of that cable clamped to the metal.

Attaching the Electrode

It is a bit too early for you to connect your battery cable to a battery. So, you need to attach an electrode to that cable. A regular welding rod is preferable to an electrode set in a pinch. A normal rod not only lasts longer and makes it easier for you to work with but also helps produce better quality welds.

First, you’ll need a slot that holds the rod securely in place. Use pliers for prying the teeth of your battery cable inward. After getting the slot, secure the rod in the clip maintaining as much of the surface contact between your electrode and clamp as possible.

If you think you need a higher amount of pressure to keep the electrode secured, you can use tie some plastic material around your battery cable clamp. The inner tube of a bicycle tire may do the trick. Alternatively, locking tools like vice grip pliers can also be used, but you may have to deal with a problem as those pliers might get in your way.

Completing the Connection

Take the end of your cable that remains free and is holding the welding rod. Attach that end to the free battery terminal which is likely to be the negative one. As you establish the connection, the welder should be hot, and you must be careful about touching anything with it or setting it down anywhere.

Covering the Car Batteries

You can’t have control over every second of your job. So, the batteries have to be given some protective covering. You can choose from plywood sheets, a jacket, or a welding blanket to keep the car batteries from getting ignited by sparks. Also, batteries may explode, which is why this protective measure should be taken.

Using Personal Safety Equipment

Since you’re thinking about welding with automobile batteries, I hope you don’t need my help to know which safety items are needed by welders on any typical job. But I wouldn’t mind giving you a friendly reminder to put on items like a welding helmet, gloves, and non-flammable outfit.

Starting the Arc

With the welder ready, you want to create an arc. Take the electrode holder, the battery clamp in this case, by your dominant hand. Then, you should sweep that electrode against your workpiece to allow it to spark and quickly flare up. You may not succeed at the first try. So, keep doing until you see the sparks.

Make sure the electrode stays at least 1/8 inch away from your metal workpiece. This distance is required to maintain the arc that melts the welding rod (electrode) as well as the metal underneath it.

Any contact between the electrode and the metal being worked on leads to a complete circuit in which case you won’t have an electric arc. Even if you manage to create the arc, it may not sustain. You should have some training to take the electrode as close as required to create an arc while keeping it distant enough to prevent the circuit from being completed.

Making the Weld

The first thing you want is to form a weld puddle containing molten metal. The arc requires some time for that. You can allow the arc to continue until the formation of the puddle by hovering over the spot on the metal where you plan to start. This way, you’ll have the first tack weld.

Locate the other end of the metal and maintain the arc to form another puddle. Don’t forget to keep every two puddles at least six inches apart from each other. The tack welds hold the work areas on your workpiece together and let you keep welding continuously.

After completing part of the welding job, you’ll see substance on the weld which looks glassy. It is the slag. With the electrode being heated, its flux starts boiling away while spewing out some shielding gas which blows away the air or contaminant to protect the molten metal from any kind of oxidation.

Sometimes, the accumulation of slag may occur in plenty. Use a hammer to strike the accumulated slag. A few strikes should break the slag away to expose whatever weld you’ve created underneath.

Improving the Weld Quality

After making a weld puddle, you can push the welding rod in a little bit so that the melt pool can be filled. Move the rod a little forward. Only half of the weld pool’s diameter should be enough. Repeat the process to make the weld better.

Choosing an Alternative to Amperage Control

Being able to control the amperage is a desirable part of the job. However, you cannot just control the settings since welding with car batteries won’t let you have it the way a commercial welding machine does. Too much amperage cause the rods to evaporate quicker than you want.

Using more than one welding rods can be a good solution. Tie 2-3 sticks of welding rods with baling wire. You may also pick up a thicker stick for the task.

Dealing with a Stuck Electrode

When the electrode you use gets stuck to your work area, the circuit gets completed without throwing an arc. This turn of action causes the rod to heat up and catch on a sudden fire. It may happen on a regular welding project too.

But it is nothing that goes beyond your control. Release your electrode from its clamp to kill the circuit. As soon as the rod cools off, use a hammer or pliers to pop it off.

Final Thoughts

I got one more suggestion for you. Some people have welding skills, but many welders don’t have much experience in stick welding. Not many people can foresee the need for battery welding.

If you are sure to go for it someday, a welding machine with a wire-feed system will come handy, particularly in case of welding 1/2-inch thick metal using automobile batteries.

That is all the information I could share about the topic. However, feel free to ask me more questions for I understand that a lot of things could happen on an unconventional task such as this one.

Safe welding!

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