I'm at the airport. Daughter calls to say the jeep died. Lights etc... come on but the car does not attempt to start. A friend goes to jump start the car. When they connected red to dead and black to frame, the cables melted. 2 sets. No other obvious heat/melting/smoke under the hood.

I had him inspect the red cable for fraying. None.

Can a battery fail across the terminals like that without exploding?

Or do I have bigger issues?

Got to be hooking it up wrong, if the lights come on. Ask for pics, show where they are hooking up.
Everyone has a cell phone.

That is my thought too but the guy helping her is no dummy.

In my experience, if the positive and negative of the battery internally short, you would visually see it’s not okay to jump the battery. My experience is solely in batteries, multi farad capacitors, and isolators. I used to have a stereo system most normal people would find either a nuisance, aggravating, or annoying. Possibly all of the above.

What you are describing is almost as if they are putting the positive jump on the negative terminal, and the negative to the frame. A vehicle with a good battery and solid alternator would cook the cables. It would be hard to do it much if any other way.

Pull the battery out if the Jeep. Hook cables directly to battery cables. Should start right up, and not bake the cables.

If that’s the case, the battery is only good for a core charge.

Have him touch the battery. If it’s internally shorting and not visible, it’ll be hot AF.

Sounds like a dead short inside the battery and the jumper cables are going to the dead short......and cooking them. Bypass the battery in the jeep and hook the jumper cables only to the Jeep cables......red to red and black to black.

I suggested the same. They have to go get new cables so they're getting a new battery too.

Sounds like a good plan so that the delicate electronics are not damaged.

If the lights came on, there wasn't a dead short in the battery. Check cable to the starter.
It may be shorting to chassis when the starter solenoid engages.

It was the battery. When they removed it, it was leaking from the bottom.

O'Reillys confirmed bad battery.

Thanks everyone!

I love it when all ends well!!

If a cell shorts out in a lead-acid battery, you'll still have voltage passing through it. It may put out 10.7 volts if one cell goes bad, but the other five can remain unaffected.

Good enough to keep the lights lit, but not much else. Now the question remains is what caused the battery to fail? Battery age? Physical damage? Thermal runaway?

Thinking that if the electrolyte was leaking from the defective cell, it may have overheated and melted the internal platelets causing the short.

With it leaking, there may be something (loose nut or stray 10mm socket) in the battery tray that caused the damage to the case.

Have her check the tray when she has time. If nothing else, clean the tray area with water and baking soda to neutralize the acid and prevent corrosion.

At this point , be happy she made it home ok .

Be sure to flush the battery area with a lot of water too, and all the stuff below the area.