When the sulfuric acid can no longer hold a charge in order to send an electrical current, the battery is considered to be dead. Your truck battery ages the material from the positive plates sheds, which is caused by the normal expansion and contraction, which occurs during the sending and the receiving of electrical current. The plates lose their capacity and sediment collects at the bottom of the battery case and can short out the plates. The short will then kill the battery immediately. In extreme hot weather climates there can be additional causes of failure such as positive grid growth, positive grid corrosion, negative grid shrinkage, buckling of the plates, or the continued loss of water.

Normally well-maintained and charged deep cycle batteries will die naturally because of positive grid corrosion, which causes an open connection. The shedding of the positive plates is an additional cause. When deep cycle batteries are left uncharged for long periods of time, short between the plates will occur when the battery is being recharged. There is a low resistance bridge in the cell, which will get hot enough and boil the electrolyte out of the cell, which causes a large amount of hydrogen and oxygen. This is the reason the vents are so important and the reason why it is necessary to recharge your battery in a well-ventilated area. Sulfation is the reason for 85% of deep cycle and starter batteries early demise. Sulfation is caused when the battery's state of charge drops below 100% for long periods of time and for undercharging the battery. Harden lead sulfate crystals coats the plates. Trying to recharge a sulfated battery is like trying to take a bath with all of your clothes on.

Hot weather is the harshest condition for batteries. It has been found the average life of a battery in those conditions to be only about 37 months. In a separate study it was found to be 48 months. The study done by Interstate Batteries found the average life to be 30 months. If you live in the area of the country, which has extremely hot temperatures and your battery is 3 years old, you may want to have your battery tested often, so you are able to eliminate it before the projected break down.

Your truck battery may just be the most important thing you ever have to rely on if you are in the trucking industry. What would you do if your batteries went south and you were left stranded with a load? It could get quite expensive and time consuming to rectify the problem, but proper and frequent battery tests with a proven and reliable battery tester should solve your problem before it emerges.