Why Would a Negative Battery Terminal Melt?

by Greg Jackson
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Cable connections for battery terminals are relatively simple, but problems can occur that will cause electrical shorts to melt a negative terminal. Fortunately, the solutions are usually simple as well.

Terminal Connections

Check all cables connected to both the positive and negative battery terminals. This would include the main power cable from the starter to the positive terminal and the ground cable from the negative terminal. Old, frayed cable ends may have exposed wires, which will cause arcing to other metal parts, resulting in a melted battery terminal.

Battery Placement

Although engine compartment designs allow for a safe battery placement that will not cause electrical shorts, after-market batteries can vary in size and height. A battery that is too close to the hood will cause a short in battery terminals when the hood is closed. This is especially true for after-market batteries that come with a plastic cradle.

Jump Starting

Connecting jumper cables to the wrong battery terminals will also result in a melted battery terminal.

Replace Cables

If the main power cable from the starter or the ground cable appear worn or frayed, replace them.

Terminal Protection

Make sure the battery terminals are not touching the hood. Remove the plastic cradle if necessary. Buy protective caps for the battery terminals.

Other Cautions

Electrical shorts that result in a melted battery terminal may also cause other problems. According to 2carpros.com, shorts can "fry" a radio or can activate an anti-theft device built in to some radios (this must be reset by the dealer). If replacing cables and installing protection for battery terminals does not correct the problem, a professional diagnosis by an ASE certified mechanic may be necessary. Jump starting should only be done with clearly-marked cables. Consult the owner's manual for the car before attempting a jump start, as some car models cannot be started this way.

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