Another possible data point.
I parked my pickup truck in the garage for three weeks at the beginning of summer. Wasn't thinking about it, but when I got back and tried to start it, the 2012 OEM battery was darn near flat. It fired, but it was close to needing a jump. Replaced the battery, but now there is a BatteryTender sitting close by, and if I'm going to have it sit over a week, it gets hooked up with the hood up to remind me.
My wife's shiny new 2016 Prius sat for a month, and the parasitic loads killed the 12 volt
battery. Guess what? That fancy pants hybrid system flat won't start unless the old-school 12 volt
lead acid battery is at least mostly charged...the 200 volt traction battery was perfectly happy, but there was no way to close the relays that heat up the electronics in the hybrid controller. Total silence--not even a warning light on the dash when I tried to start it--heck, I had trouble getting the door open!
The dealer was kind and warranty replaced the destroyed battery. The Prius fleet now also has a dedicated BatteryTender close at hand next to each of their normal parking bays.
Rich, KE4GNK/AE, Overkill Engineering Dept.
'The Silver HamShack' ('07 International 22FB CCD 75th Anniversary)
Multiple Yaesu Ham Radios inside and many antennae sprouting from roof, ProPride hitch, Prodigy P2 controller.
2012 shortbed CrewMax 4x4 Toyota Tacoma TV with more antennae on it.