Newbie here! Great to discover this forum, very useful for novices like me!

Question regarding battery draining.

I am planning to park my 1 year (8k miles) X3 for about 24 days. I will roll up all the windows and lock the car. It will be parked inside the garage, where the temp should be between 55 and 70.

I am assuming that no electronics run in this "shutdown" state. Is that correct? Either way, do I still need to connect a battery tender/maintener while I am gone? In case I do, any opinions on the Schumacher 1.5amps maintener?

Thanks!