You do not need a tender for 1 week!
There are a few ways to test, depending on your skillset. But first, have you installed anything lately that would have a draw on the batt?? Is this a new problem or just the first time she sat for a week?
A volt meter is easy to use or even a test light can be used, depends on what you have at hand.
Watch this:
https://www.youtube.com/watch?v=zdIKNnwEjIs
Hybrid Mode
