We’ve all had a battery go flat, and when that happens you have to search through the trunk to find your battery cables. What you may not know is that not all battery booster cables are created equal. In fact, most cables out there are not good enough for the job at hand. The issues come when you have a fully dead battery, and need to get it up enough to get the engine going. If your cables are not in good repair or low quality, it may be a futile effort, and it could result in a fire.
Booster cables work by transferring electrical current from one vehicle’s battery to another. While that sounds simple (and it is) the cables must meet certain specs to transfer the level of current needed to start an engine. Most engines require several hundred amps to energize the starter, crank the engine, and operate the rest of the electrical components to get the engine running. Even though the cranking only lasts a few seconds, a massive amount of current must flow through those cables. That transfer of energy has a byproduct of heat that is released through the clamps and the wire itself. The smaller the cables, the more resistance they have to that flow of electricity, which means they generate more heat. Eventually the cables will melt and then you have a dead battery that is on fire.
The clamps are just as important as the cable itself. Loose clamps don’t conduct well, and neither do rusted or deformed clamps. Cheap cables are often made with small gauge wire, cheap clamps, and are generally not well built. It may seem silly to spend more on booster cables, but you might rethink that philosophy when you can’t get your car started in two-degree weather because you bought the cheapest cables you could find.
Here’s what to look for in your next set of battery booster cables.
The gauge of the wire is critically important. Cheap cables are typically made with 10-gauge wire, which will start a small 4-cylinder engine with a low battery that is just a little too low to start the engine on its own. But if you have a big V8 engine and a flat battery they are not going to get the job done. You need a minimum of 6-gauge wire to transfer the necessary energy to start your vehicle. 6-gauge is considered medium duty, which will start most passenger vehicle engines with a fully dead battery. If you have a diesel engine then you need 4-gauge cables, which are heavy-duty. Read the packaging for the details, as even some 10-gauge sets claim to be heavy duty.
The minimum length of booster cables is 12-feet. Anything shorter means that you may not be able to reach from one side of the dead vehicle to the running vehicle. Longer is better, but with that extra length comes the need for a larger wire gauge as the current capacity decreases as the wire gets longer.
The clamps are important and vary wildly from brand to brand. You want to look for all-steel construction on the clamps themselves with heavy springs to hold them closed. The terminals of the clamps, the actual jaws that grip the battery posts, must be made from copper to get the best conductivity. Stay away from plastic clamps as these may break when you need them the most. Insulated clamps are better than uninsulated clamps as this prevents accidental sparking if the clamps should touch while connecting them.
One thing that is often overlooked is smart connection monitoring. It is not necessary, but hooking up battery cables backwards is potentially catastrophic. At best you are looking at a big spark show, but it can also cause a battery to explode which can be deadly. Smart cables notify the user when they are not connected correctly and prevent the flow of energy, protecting both vehicles and the people working on them. For example Mychanic Smart Booster Cables feature a gauge on the fault protection circuit which shows how much voltage you have flowing to the dead battery. One of the most frustrating things when jump starting a vehicle is not knowing whether you have a good connection. The gauge tells you if you are properly connected and have full voltage flowing. If your gauge reads 10 volts, you are never going to get that engine going. You should see between 12.5 and 14.4 volts if the cables are connected properly, and the donor battery is feeding full voltage.
Whenever you have a dead battery time is usually a factor. Smart battery cables get you safely connected faster so you can start the engine quickly and get on the road. Make sure you have the right tool for the job so you aren’t stuck walking around the parking lot asking strangers to borrow their booster cables.
Check out all the batteries, cables and related parts available on NAPA Online, or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to choose the best booster cables, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.
Photo courtesy of Public Domain Pictures.
A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.