What would cause my battery to go completely dead

Hello, no matter what the vehicle, a battery that loses its charge can do so for the following reasons. First, the internal lead plates and sulfuric acid mixture that makes up the lead acid battery could lose its ability to create and hold a charge. This means a surface charge could be present but under any kind of load, fails. Secondly, the charging system of the vehicle may fail to properly recharge the battery. Third, a parasitic draw may be present, causing the battery to be drained while the engine is off. I would check for each of these 3 issues in that order, and you will determine what is needed to be done to resolve your issue.