Here’s a little advice for the best size jumper cable size to keep in your car or truck. I’ve included a general-purpose jumper cable gauge chart too. And my current recommendations for consumer grade and pro grade jumper cables for a typical car, or a heavy duty truck.
Did you know that cold temperatures will greatly reduce your car’s battery capacity? That’s one very good reason why it’s a good idea to keep jumper cables just in case. Another is being a good Samaritan for others.
As a car battery ages, it will become even more susceptible to poor starting, especially during cold weather. In fact, a car battery can freeze solid in cold weather if it becomes too weak!
If a car battery has a full charge, it will not freeze unless temperatures drop to 76-F below zero. Unless you’re living on Mars (or maybe Alaska!), you will likely never face that kind of cold! Your car should start in cold weather if the battery is in good condition and fully charged.
However, a partially charged weakened battery will be susceptible to cold temperatures. Often our vehicles don’t get an adequate charge from running short errands here and there. In this case, the battery slowly drains, especially as the battery ages. If a battery has become fully discharged, it will freeze solid at 32 degrees F (which will permanently ruin it).
Best Jumper Cable Size (Gauge)?
The thing with wire size is this:
Size matters.
– The smaller the wire diameter the less power it can handle.
– The larger the wire diameter the more power it can handle.
When starting a car engine it is amazing how much power gets sucked from the battery. In other words, a typical car starter requires a lot of DC Current (Amps) to start the engine.
How much current flow? How many Amps to start a car?
It varies depending on the engine, temperature, and battery condition. Generally, a typical car requires about 300 – 500 ‘Cranking Amps’ from the battery while starting.
Diesel engines require more because they have a very high compression ratio. A diesel truck engine may require as much as 1,000 Amps during start-up!
Note: The colder it is, the more Amps are pulled from the battery. Why? Cold temperatures will lower the vehicle battery voltage, which will increase the demand for current (Amps) needed to start the vehicle.
Note: Car batteries are rated with Cold Cranking Amps (CCA). It is a rating for Amps that a battery can discharge in 30 seconds at 0 degrees Fahrenheit while maintaining full charge voltage. The higher the CCA the ‘beefier’ the battery.
Wire Gauge For Jumper Cables
Now that we know how many Amps may flow through jumper cables, we can consider the wire gauge size.
It’s all about gauge (and the wire material).
Jumper cable gauge refers to the thickness of the cable’s wiring.
Jumper cable wire is usually made of copper-clad aluminum. It’s cheaper than copper stranded. However pure copper wire is much better (in several ways)! But it does cost more. And it’s heavier. More on that in a minute…
Note: When looking at wire gauge numbers, the higher the gauge (numerically) the thinner the wire. The lower the gauge number the thicker the wire.
The best jumper cables will be those that can flow the most energy from one battery to another. Thicker jumper cables (lower gauge) can transfer more power than thin jumper cables.
The following chart is a general guideline.
The gauge and amps are directly from various jumper cable manufacturers. I have averaged and summarized their data to help figure out what gauge jumper cables you might need.
Sometimes they vary among manufacturers (even for the same gauge). But that is because of wire material differences, and other factors (including Marketing)…
Jumper Cable Gauge Chart
0 (900 – 1000 Amps)
1 (800 Amps)
2 (600 – 800 Amps)
4 (300 – 500 Amps)
6 (200 Amps)
8 (they don’t say)
10 (they don’t say)
10-gauge jumpers may be good for ATVs, motorcycles, snowmobiles, etc.
I would not bother with 6 or 8 for any car. Even though manufacturers may say they’re good for small or mid-size vehicles, I like to have some margin! Especially if I’m stuck with a dead battery!
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For most cars, I recommend 4 gauge jumper cables. 2 Gauge for full-size.
4 Gauge x 20 Feet, 500 Amp
(EPAuto on amzn)
4 Gauge x 15 Feet – Among the best you can get
(Spartan on amzn)
For heavy-duty trucks, especially diesel, I recommend 1 gauge jumper cables.
1 Gauge x 25 Feet, 800Amp
(TOPDC on amzn)
1 Gauge x 15 Feet – Among the best you can get
(Spartan on amzn)
Spartan, made in the USA – One Of The Best Jumper Cables
Okay, are you looking for the best jumper cables? Well, I can tell you what I bought many years ago, and why I bought them…
Pure copper-stranded wire, through and through. It’s the best. Here’s why…
One thing that can happen to common jumper cables made of copper-clad aluminum… They can (and likely will) eventually crack, and lose continuity. Then you’re SOL. This has happened to me with several consumer brand sets that I’ve owned in the past. They also get VERY STIFF when cold. Annoying to wind up. Pure copper stays flexible and won’t crack.
Spartan cable clamps are also very well designed. Each clamp (black and red) has two biting jaws that grip the battery post. Each one of them is powered via a copper-stranded interconnection.
Yes, they are comparatively expensive. But the peace of mind is well worth it in my opinion.
This is the brand of jumper cables I bought for my truck (from Spartan, made in the USA – actually Reno, NV if I remember correctly),
15 Foot 1/0 AWG Booster Set
(Spartan on amzn)
My set:
Here’s something really nice about these… BOTH sides of the clamp are powered. Most jumpers are only connected at one side of the clamp grips.
Tip: There’s also a product called a Jump Pack which has a built-in battery designed to jump-start a vehicle:
Jump-N-Carry, 1700 Peak Amp, 12V Jump Starter
(Clore Automotive on amzn)
Truck PAC, 3000 Peak Amp, 12V Jump Starter
(Clore Automotive on amzn)
[ Read: Battery Voltage State of Charge Chart ]
