Hi Dave, you may want to have the battery load tested. Terminal voltage test of 7 (or so) volts is NOT GOOD for any period of time. If it 'sulfated' the capacity would be diminished. A load test would answer this question very quickly. If it went south because of it self discharging too long, you might have to replace it. Hope the load test comes out OK!


A battery 'exploding' can be a number of reasons. An internal short, a charger incorrectly hooked up (have seen this happen way too often), a 'short' across the terminal posts (dropping a wrench/screwdriver, happens a lot as well). Sometimes, while high current charging, too much hydrogen gas is present and if a slight spark (checking the chargers clamps on the battery being charged) and 'BOOM'. I reference a wiki article for the prior sentence " Car batteries are most likely to explode when a short-circuit generates very large currents. Car batteries produce hydrogen, which is very explosive, when they are overcharged (because of electrolysis of the water in the electrolyte). The amount of overcharging is usually very small and generates little hydrogen, which dissipates quickly. However, when "jumping" a car battery, the high current can cause the rapid release of large volumes of hydrogen, which can be ignited explosively by a nearby spark, for example, when disconnecting a jumper cable. When a battery is recharged at an excessive rate, an explosive gas mixture of hydrogen and oxygen may be produced faster than it can escape from within the battery, leading to pressure build-up and eventual bursting of the battery case. In extreme cases, battery acid may spray violently from the casing and cause injury. Overcharging—that is, attempting to charge a battery beyond its electrical capacity—can also lead to a battery explosion, in addition to leakage or irreversible damage. It may also cause damage to the charger or device in which the overcharged battery is later used."


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