In a recent rig incident a 12 volt battery exploded while being jump started. The 12 volt battery was fitted to the Pressure Test Pump. Booster or jumper cables were connected from the 12 volt battery to the 24 volt battery of the Forklift. The Pressure Pump was in the vicinity of the Catwalk at the time. The individuals who attempted to jump start the batteries were obviously unaware of the difference in voltage and the correct method of jump starting a battery. Fortunately the battery was the only casualty and there was no injury to personnel.