Glowing battery cable

[Jedon]

I take it that's bad? I immediately cut power and disconnected that battery from the bank as soon as I saw it.
I checked the voltage this morning on that battery and it was 6.38V so perhaps it was just bad wires?
I had used 4 smaller wires since I ran out of big cables, I guess that was a bad idea.

[mike90045]

That's a reason soldered connections are bad ideas for large currents.  They would have come loose, and not stay attached.  Nice pic too!   What was the load they were driving?

[Jedon]

I ran out of good interconnects when wiring up this spare battery bank so used 4 smaller wires that just had crimped on connectors.
I forgot to turn the well pump off before shutting the generator down so the load was around 18A @ 120V
Since money is tight I think I'll just replace that battery, it seems okay voltage wise but the post is loose so I would have to clamp something on the lead base or something.

[Lloyd]

Batteries sure hold a lot of opportunity to do some damage.

Another issue I see in the picture is the ground cable, it appears to be welding cable. It also looks like it has a very high resistance due to to corrosion.

Even though welding cable is capable of carrying very high amperage, it has one fault that leads to trouble. The copper strands are sheathed in paper,before the insulation. The heating and cooling of the cable in use, especially if used in an uninsulated space...Results in moisture wicking  far up the cable(paper draws the moisture up like a straw), and corroding the copper causing more high resistance.

I have personal cut apart welding cable on 4 or 5 installations that I have been on to re-wire. When I tell owners that they have a potential problem they are in disbelief, until I cut the cable mid run and drain water out.

Next issue is the multiple stacking of lugs on a battery post will also result in high resistance. The codes say you can stack up to 4 lugs, but this is bad practice. I find a better solution is to take one cable to each battery lug then to pos and neg buss bars, make your multiple connection there.

Battery lugs; use lead coated copper crimps, tin plated lugs are not compatible with the the battery acid. Acid spills and fogs will eat away the tin and leave a bare copper lug that will corrode in to a high resistance connection. Be sure not to use the automotive lugs, the kind that are open at the end, use a closed end lug, with heat shrink. As Mike pointed out don't depend on a solder only connection.

Fuse at the battery with a terminal fuse. They are very inexpensive and can save lives. They come in sizes 30 to 300 amp. if you need higher current use a class t fuse as close to the battery as possible.


Last but not least, using multiple conductors to carry a high amperage load is a bad idea also. As you can see by the picture if a high resistance develops in one or more of the conductors, that leaves an under sized cable trying to carry a high amp load, which results in a glowing wire and melting insulation and possible fire.

Electrons follow the path of least resistance, as the old saying goes...but don't forget they will follow all paths they see. One being a wet and dirty battery top.

Lloyd