Why does battery dies when truck sits for a couple of days? on 2008 Hummer H2

When I hook up charger there is a faint buzzing sound coming from a small canister near the fuse box. It will buzz for a few seconds then stops.

Asked by for the 2008 Hummer H2
2 answers
Since all batteries create power by a chemical reaction, we say that the chemicals have exhausted themselves in the reactions. This would mean that a dead battery is exhausted.

have the battery tested (high rate discharge test and or hydrometer test)an inductive amp meter would be needed to see if there is a parasitic draw on the battery (something staying live when the ignition key is off).