Small vs. large gauge jumper cables

Would the gauge of the jumper cables make a differenc After several attempts with the smaller cable, we switched to a heavier cable and it started on the first turn of the key. I don’t see how that could matter. Usually, after cranking the key a few times my little cables would feel warm (they have worked until yesterday). Yesterday they were cold after attempting to jump start my truck. It’s like there was no current going through them. Weird,huh?

Not weird at all. Wire gauge and length make significant difference.
If not, we would use 20 gauge or smaller for everything.


I have used a set of #4 gauge jumper cables I bought 50 years ago ever since. They have never failed to start whatever I’ve hooked them up to.

I have a set made from 2/0 welding cable about 30’ long, heavier than heck, but they never failed to start what I hooked them up to, even semi to semi.

Worked at a recycling center in the late 70’s and got the cable for scrap value maybe $10 at the time, bought the best clamps I could get, think they were $40 for all 4.

Still have them.

The guage and clamps make a huge difference, the thicker the better and since it seems like the only time you.need them is when it’s raining, snowing, in the freezing cold or blistering heat, at night in a sketchy area, this is no place to go cheapo.

Had a pair of the discount, thinner guage for occasional jumps of a little used garaged car and discovered that when I really needed them, between the corrosion on the poorly designed clamps and the overheating of the thin wire they were practically useless.

Since today’s cars will shut down completely from a weak battery, with little or no warning, Mrs. Beancounter enthusiastically approved the quality upgrade. Happy wife, happy life.

A little descent here. Sure heavier cables are best but in this day and age of highly expensive electronics, I would not jump another car. Yeah you can be caught by surprise but trying to get ten years out of a battery can cause unexpected failure. Better to change batteries sooner. I do carry one of those small jump packs just in case someone else needs it but jumper cables will not touch my cars.


Master Mechanic Pat Goss (recently deceased… ) agrees with both you and me.

This is a good reminder for me to recharge my Cobra Jump Starter.

I agree with @bing. Modern cars need a jump pack to protect the electronics. If your car is more than about 15 years old, then jumper cables will be OK.

That’s very nice of you: thanks.

I bought two lithium-ion jumpers, time to buy a third, they don’t last any longer than the lead-acid jumpers. If you carry one of these, how do you know if it has the strength to start an engine?

My back-up is a 12-year-old battery that gets recharged every 3 years. OMG, jumper cables!

My torrent has top post. My vue has side post. My equinox has side post… Why does torrent use top post? Hard to jump side post. Restricted access to battery clamps.

5 awg wire resistance is 0.0003 ohm per foot. Doesn’t seem like much but w/100 amp flowing during cranking attempts the voltage drop is 0.6 volts for a 10 foot run or two wires. That subtracts from the voltage needed at the starter and could be enough to prevent cranking.

Also discount jumper-sets (from my observations), the sort offered at flea markets etc, new products, seem like they use less expensive wire material and may not meet the resistance spec’s for the wire gauge they are advertised to use. The electrical bond between the wire and the clamp can be suspect as well.

As mentioned above, what w/the price of car electronics these days, I wouldn’t recommend either giving a jump start, nor receiving one, except in an emergency situation. I just recharge the battery overnight using a battery charger.

I use a lithium jumper pack thing that I got at Costco. It’s about as big as a VHS cassette (remember those?) and has thin and light weight cables and small clamps, but it starts a dead car pretty well, often on the second try. Almost feels like the first try “wakes up” the chemical reaction inside and then there’s enough power to start the engine on the second, but what I know about the chemistry of electric generation is ZERO. Anyway, it works.