Symptoms of Loose Battery Cables

One of the most frustrating problems drivers face is issues with the car battery. It can be expensive, albeit easy to replace, but the main issue is not being to start the car without it.

However, the symptoms of a bad battery aren’t that different from symptoms caused by loose battery cables. In this guide, we’ll go through the symptoms, how to properly identify the problem, and repair it without the help of a mechanic.

The Symptoms

Loose battery cables, otherwise known as terminal ends or clamps, are the rings that connect the battery to the car. The most important job of the battery is to provide a massive surge of power to crank the engine. After that, the alternator takes over and generates power, while the battery is slowly refilled.

The primary symptoms of loose battery cables are the complete failure to start and visible signs of power loss during driving. The first symptom is shared with the battery and the starter, while the second can be caused by a faulty alternator.

If you’re facing these problems, you should always start your inspection with the battery cables, as they’re the easiest to check and require no tools. The battery is perfectly safe to operate and won’t shock you. When you’re removing cables, always start with the negative, or black, and then remove the positive red. Installing the battery goes in reverse – red first, black second.

Grab the cable and wiggle it to see if it can be rotated off the battery terminal. Look for signs of rust, on the clamps, and see if there are any visible rips in the first few inches of the cable. Take the cables off, and look at the condition of the battery terminals, as well as the inside of the clamps.

Tighten Up the Terminal Screws

Once you’ve confirmed that loose cables are the problem, the easiest solution is to see whether you can tighten up the terminal screws. If you’re not able to tell the screw size by eye, try to read the engraving on it, or use a basic ruler to get the approximate size. It should be either 10mm, 13mm, or 5/16″. Alternatively, a nice set of wrenches ensures you’ll have the right tool for the job.


Slowly rotate the screw and check if the clamp is secured. Don’t force it too hard, otherwise, the screw will chew through the clamp groves and render it useless. Repeat the process for the second clamp, then try turning on the car. If the engine starts normally, it means you’ve solved the problem.

Clean Battery Connection Posts

Battery terminals are the two smooth posts that connect to the car’s cables and complete the circuit. If the cables do not appear loose, that doesn’t eliminate the possibility of poor connection – corrosion naturally appears on these components, and should be cleaned to restore proper metal-on-metal contact. We’ll explore a few methods of cleaning the terminal clamps and posts.

Battery Cleaning Agent

For this method, you can use any battery cleaning solution, but I like the CRC battery cleaner because of the acid indicator. Disconnect the terminals, then apply cleaner on the top surface of the battery. CRC will foam and turn pink in contact with acid. Leave it on for a few minutes, wipe down and apply again. If the foam doesn’t turn pink, you’ve properly cleaned the battery.


Baking Soda

While battery cleaners have several applications, it’s understandable if you don’t want to spend extra cash to solve this problem. What you can use instead is some baking soda and water. First, disconnect the cables, then put the baking soda on the terminals. You can use a toothbrush or anything handy to maximize surface coverage. Slowly pour a small amount of water on each terminal, and let the chemical reaction happen. Rinse, repeat if necessary, and let it dry before reconnecting the cables.


When I can’t find the battery cleaner, I typically resort to using some sandpaper instead. It’s the fastest method, and while it doesn’t do as good of a job as the cleaner, it’s good enough even as a long-term solution. Take a piece of sandpaper the size of a credit card, fold it, and wrap it around the battery post. Rotate it as if you were tuning the radio, and that should be sufficient to clean the posts. For the terminal clamps, put the paper through the hole and work the interior.

Replace Cable Terminals

I’ve heard about people using copper wire, sheets of tin, and other conductors to form a connection. Cars deserve proper maintenance, so if you see this as the solution to your problem, at the very least get a couple of battery post shims and do the job properly.

The best solution is to replace cable terminals completely. As it does not involve soldering, the task is fairly easy, requiring only a pair of pliers, cable terminals, and that set of wrenches you’ve used to disconnect the battery.

With the cables disconnected, cut off the terminal while leaving as much of the cable as possible, then tighten the cable end into the new terminal. Take a look at this detailed guide on how to do it:


Can a loose battery cable prevent the car from starting?

It can, but it is not the only cause. A failed alternator or a battery is much more likely. Once properly secured, battery cables do not come loose and maintain the connection for a long time. However, troubleshooting should always start with a cause that has the easiest and cheapest solution, so if your car has starting issues, battery connections should be the first thing to check.

Can loose battery terminals drain the battery?

The cables complete the electric circuit, so they don’t leak power or kill the battery. However,  the battery won’t be charged properly as you drive, and it will get drained until empty. Not having a consistent power supply can mess with a vehicle’s electronics, especially with modern vehicles, so if possible, avoid complete battery drain.

Can a loose battery terminal cause a car to die?

This is a layered question and comes down to whether the vehicle will run with loose battery cables, and whether there’s a potential of damaging the electrical components. I cannot recommend driving with loose battery cables, especially considering how easy and inexpensive of a problem it is to fix. At most, drive the vehicle to a mechanic or the closest parts store and get the cables swapped as soon as possible.

Why do my battery terminals keep corroding?

Battery corrosion is a chemical reaction between hydrogen gas, air, and metal surfaces. It’s a common occurrence that is easy to fix, as explained in this guide. You might want to consider maintenance-free batteries that are advertised as corrosion-free.

Which battery terminal do I connect first?

Positive, then negative (red, then black). When disconnecting the battery from the system: negative first, positive second (black first, then red).


Examing or even changing cable terminals is a quick job you can do whenever you’re unsure what is causing the power issues. However, the damage and malfunction are very obvious, so don’t unnecessarily shorten the cables. We’ll cover battery problems in another article, so stick around and learn more about vehicle maintenance and repairs!