Guys I got a 1200a jump starter that doesn’t jump start my truck.. I have a 5.3 vortex in my Chevy Silverado.
It’s had a full charge ( jumper) but it didn’t even do a thing to the battery.
So I decided it needed jumper cables and I took my cables out and waited and waited for the battery to take charge and it didn’t do anything.

A fella who saw what was going on said he had a heavier set of cables and to give them a try.
We put them on and BAM fired up.

All connections were tight,, because the jumper gives the okay when the connection is good.

Here’s my question.
Is a 1200a not enough strength to jump start a 5.3 vortec?
Does a heavier set of jumper cables really matter?

Heavy set makes a difference for sure. But your jumper should start that motor with no problem. Next time try removing cables from battery and hook box directly to cables. If it starts, you’ve ruled out jump box. In that case battery is probably so dead it’s pulling all the juice from box without sending any to starter.

I used to have a V8 Scout II. jump start it, I had to drive my other car up to the Scout until their bumpers touched. This completed my ground connection between the two vehicles. Then I would put both jumper cables on the positive terminals and crank the Scout.

A heavier gauge pair of jumper cables was needed to carry the necessary amps.

take your batter cable ends and cut the plastic garbage off them so you have the metal against the lead of the battery

GM side terminals start with too little surface area and when those cables swell from summer heat then goes cold they make your connection worse.

you can have a perfectly running truck and a perfect brand new battery and if you are trying to get all the current you need to start through just the bolt it isn't enough

dealt with this 2 years ago on my 2004 gmc 1500 at 17 below , then tried a couple days later another fully charged battery and still wouldn't , cut the plastic off the terminals on the end of the cable and tightened them down and good to go

jump boxes , jumper cables if you keep hooking on that bad connection you get nothing tried it all that night.

I have a professional set of jumper cables like you would find on a tow truck.

26ft - #2 gauge - copper - approx 25lbs - $225


Night and day compared to normal cables. Starts right up with vigor. Huge difference.
I joke with people that they could start a battleship.

Once you have a set like mine , you will never go back to ordinary ones. I also never let anybody borrow them.

I would guess that your jump pack just looks for some voltage from the battery to give you the okay, but it can't actually make sure the connection is capable of flowing enough amperage.
Think of it this way.....if you connected your jumper cables/jump pack with a single strand of copper wire, you'd have 12V (or whatever your battery has available), bur of course that single strand of wire wouldn't be able to conduct enough amperage.

Good jumper cables make a difference, and you can't tell just by looking at them. Sometimes they'll have think insulation to make it look like a big cable, but inside, it's just 10 gauge wiring, which is only capable of carrying around 60 amps.

I have a Stanley brand jump pack that includes a tire inflator along with some USB ports to charge electronics. (Stanley FATMAX 1200 Amp peak jump starter with power station).
It works good to inflate tires.
I have tried twice to jump start recently dead car batteries (a honda pilot, and a some other small suv) and both times the jump box did not have enough to turn the engine.
The second time I thru my jumper cables in the truck, attached them to my truck and suv and viola!, started right up!
I was thinking the Stanley jump box (from Sams Club) was defective in this area.

if you are clamping them to the crummy little side terminal bolts , it won't matter if you have massive cables if your only catching 2-3 threads

If possible, connect the jump leads (box or cable) to a positive post by the fuse block (if equipped) and a solid engine ground.

It is always best if you can make your final connection to a good ground as opposed to connecting to the negative battery terminal. Batteries can leak hydrogen gas , especially when trying to jump start or charging a battery.

I have had two batteries do this over the years when trying to jump start them before I learned better. One of those batteries when I made the final connection to the negative terminal , I heard a tiny crack as it sparked when I connected it.
Hydrogen burns with no color in the flame. I backed off , seconds later the top of the battery blew off. Luckily I had stepped back. I knew a guy who was not as lucky and had a battery do that as he was leaning over the battery. Sulfuric acid went right into his eyes. He could not see and was working alone. He crawled up his front walkway groping for the sidewalk with his hands. Groped his way into the house and to the kitchen sink to flush his eyes out. Lucky , no permanent damage.

Before you spend money on better cables or another box, buy a new battery you won't have to jump.

(I'm not being smart)

The once a year NAPA battery sale is best I have found.
I did not say cheapest. <-- garden tractor too
Single digit cold here.

But!!!

Check your connections first, those side mounts can be tight but still not connect.

The side terminals are terrible. Remove the black and red plastic protectors on the terminals and through them in the trash. You'll likely find the terminals on your cables covered in white/green corrosion. Just sand it off.

New fasteners are cheap.
The longer ones fit jumpers better.

Like he said, be mindful of exploding bats.

General jumper cable advice here-sometimes the wire to gator clamp connection gets rusty/dirty/corroded. Take a chisel or punch and whack the little metal piece that holds the cable to the clamp. If real bad disconnect and cut down to good wire and re attach. When you can, like a tractor, put jumpers on starter and do away with the middle man.

X2

I never was able to get a good connection on a.side terminal battery with the standard clamps. Heaviest cable you can get will drop the resistance giving you more juice to the battery. But it may not matter if the connection can't carry it. I changed all the terminal bolts to add extensions to all the side terminal batteries.

you can jump an average vehicle with a 20 volt drill battery if connections are good.

Thanks everyone for the replies