Electrical - battery drain

[Larry Herman]

Most modern cars have quite a bit going on, even when shut down for the night.  Little systems draw power from the ecu to the radio etc.  You can use a digital meter with a DC amp function to measure the current draw at rest to see if it is excessive.  It is possible that something is not going into its "sleep mode" and is continuing to draw power at a normal "on" rate.

In any event your car should easily last a month or so between charges with the battery connected.