Peterbilt 379 Smoke from battery wires

That truck is probably OOS until the basic battery pack is load tested and examined with test equipment electrically for health and damage if any. This may require a shop.

Starting there. You basically will need to have a mechanic go over each of the big wires and eamine them, follow them and hunt for the short that is a problem.

Im sorry I cannot offer a answer, only a starting point. It's a huge can of worms when something that basic shorts. These are not car batteries we are dealing with deep cycle packs that if not treated with respect can seriously and absolutely put one or more people into the chemical burn ward for weeks and months, rob vision pernamently and light that truck on fire. There is a gawdgum bunch of power in them things.

Be very careful.

 

Obviously a cable near the battery is rubbed raw. Further down it would be fused. Start chasing.

 

There are times when people need to step up with the money and have professionals deal with issues, this is one time.

IF he can't afford a few hundred to ensure the truck doesn't burn to the ground, then he needs to be a company driver and get rid of the truck.

 

∆∆∆ what @Ridgeline said. And maybe the truck doesn't burn. Maybe you fry a $3000 ECM

 

Was it wires burning or the batteries boiling?

 

One hit wonder or he figured it out.

 

Or even battery positive and negative terminal bolts not tight. When was last time he serviced his batteries?

 

Had a Freightliner Classic that did this just when I shut down for the night.
In my case, it was a wire that went to a boost post that was rubbing on a bolt.
So I’ll probably be something like that.

 

where they leave the battery box in back of box mine are wrapped in rubber so they don't rub through good luck