I had the same thng happening - the battery exploded half-way through charging it, one of the connecting clips must have moved and produced a spark. Initially I heard a loud bang and then smoke and smell. By the time I went around to check I could not see anything obvious. Then I saw liquid on the ground and tracing it back it was the battery that had split in half, still intact at the bottom, so held together, and still capable of running the car...