Battery terminal melts

[WalterM6]

"All the terminals are clean, not loose, snug fit, not over tightened and cables are new." Plus you have new batteries. If all of this were true you wouldn't be having a problem. Check again for loose connections. Be sure to torque terminals to 100 in/lbs. Also try moving connections side to side. If it moves it means the bolt is broken free of its lead casing.

[ThreeCW]

Originally Posted by Robert L.

New battery main negative connection melted and exploded battery after 6 months ... All the terminals are clean, not loose, snug fit, not over tightened and cables are new.

As other have said, melted terminal are caused by excessive resistance ... which causes heat buildup ... which can result in a melted battery post.

I bought new Trojans earlier this year ... and followed their install recommendations of when torquing up the connections (see attachments). Most golf cart Trojans have the embedded stainless steel posts which are only torqued to 95 to 105 inch-pounds ... which converts to ONLY 8 to 9 ft-lbs. I have a 50 to 250 inch-lb torque wrench, and torqued them accordingly and I could not believe how LITTLE 100 inch-lbs is ... if torquing without a torque wrench, I would have surely over torque them.

The problem with over torquing is that the stainless steel stud can break away from the lead in the terminal ... which in turn will cause a poor connection between the stainless steel stud and the lead post ... which will result in resistance ... which will cause heat build up ... which can lead to a melted post.

If not over-torquing, then the connections between the battery cables and the connectors on the battery cables could be a problem. Look at the attached Trojan thermal plots for more information. Trojan says in the attached guide:
"Connectors that are mechanically crimped to the cable’s end will create a high resistance area.
At high discharge rates, this resistance can create enough heat to melt the terminal post on the battery and/or melt the adjacent insulation on the cable.
Faulty connection can negatively affect the performance of a battery system and is the leading cause of most battery terminal post meltdowns."

As others have suggested, it is perhaps time for new, high quality cables.