How to Use a Soldering Gun on Batteries

Using a soldering gun to connect leads, positive and negative contacts, on battery terminals is best accomplished through quick and careful soldering. If you are new to soldering, it is best to practice soldering other things before attempting to solder on battery terminals. The procedure itself should take less than a minute once the soldering iron heats up and you are familiar with the procedure.

Difficulty: Moderate

Instructions

Things You'll Need:

• Sand paper
• Battery (AAA, AA, C, D, or 9-Volt)
• Rosin core solder
• Soldering gun
• Wire (the thinner the better, 18 gauge or smaller is fine)

1. Put on your safety goggles. Sand the terminal of the battery that you wish to solder. Make sure that the terminal is clean and clamp the battery to make sure that it stays put while you are working.

2. Strip the end of the wire for one 1/2-inch length and and it. Twist the stripped end into a loop that forms a complete circle. Make the loop small enough that the extra wire at the end is able to be bent across the diameter of the loop.

3. Straighten a 7-inch section of solder (which is longer than you really need but gives you a place to hold the solder. Gently sand the tip of the soldering iron. Heat the soldering iron up so that it is hot enough to barely melt the solder.

4. Test the soldering iron periodically by rubbing the tip of the rosin core solder on the tip of the soldering iron. Wipe off the melted solder onto a wet sponge after coating the entire tip. This helps to remove oxidation that happens naturally on the soldering iron.

5. Clamp the soldering iron so that it does not move around or get in the way. Point the soldering iron away from you as you work (you only need the hot tip of the iron). Use the hot tip of the iron to heat the wire and solder with your hands above the work so that solder will not run down onto your hands.

6. Melt the solder and use the tip of the melting soldering wire to tease the solder out to fill the loop of wire with solder. Immediately, before the flux core (rosin) burns off completely, touch molten the solder to the battery terminal.

7. Bring the solder loop and the battery closer to the soldering iron and use the soldering iron to "tap" the solder so that it stays hot without heating up the battery. When it feels like the solder has a grip on the battery as you wiggle the wire, immediately remove the wire/battery solder joint from the soldering iron and allow to cool. Use the same process on the other terminal but do not allow the wires to complete a circuit.

Tips & Warnings

• Do not take more than 2 seconds of heat to the battery. If it takes longer than this, let the battery cool completely inside and out, and then try again from the beginning.
• Do not overheat the battery since, even in the process used in this article, there is a severe risk of the battery exploding violently. Heat the battery only enough and only long enough to get the job done. Wait for the battery to cool completely and start over (on that terminal) between attempts if your attempt takes more than two seconds. Always wear goggles and sleeves to protect yourself from sharp objects and heat/solder splatter. Do this procedure in a well ventilated location where you are free from distractions. Do not do this around children, pets, or anyone else. This procedure is potentially dangerous, even for experienced soldering technicians. This article was not intended for soldering batteries in series. Never solder batteries in a series unless you know what you are doing and the risks involved. Do not solder scuffed batteries (the kind were the positive and negative terminals are not isolated to the opposite ends of the battery).

References

• Basic Soldering Techniques

Resources

• Soldering To A Battery (Short Video)
• Soldering Battery Terminals For Cars (Video)
• Battery Pack Soldering (Posted Article)
• Scuffed Batteries Short out and Burn/Explode