This is probably one of the most serious and damaging accidents that can happen to any battery owner. Loose cables that are not properly installed can and most likely will damage your batteries. Allowing for loose connections is just asking for a spark/arc to occur which can melt your posts. Those connections need to be tightened down and checked regularly for loosening bolts. Shock and vibration can cause your bolts to loosen alone but even technicians and others that install batteries are not exempt from not tightening down bolts on batteries enough. Remember as well to use those lock washers as they will help to prevent your bolts from loosening. The order from lowest connector to highest is connecting lugs lowest and closest to terminal connection then lock washer and finally bolt. Tighten to specification and you should be good to check back on your connections every year or so. In conclusion save yourself from a very scary experience and from destroying your batteries by doing a little due diligence and checking those bolts to make sure they are tight.
Oct 7th 2020