Advice on Best Way to Cool Florida Garage - Prius 4-2016

We also live in the south.
We have a plug in hybrid that we not only keep in the garage but also charge it there. We have no special ventilation, and the car has done just fine. The car is now almost 7 years old and has 78,000 miles on it, battery is just fine.

The car we traded in on the plug in hybrid was a 2008 Prius - it was kept in the same garage- the Prius was 12 years old with 120,000 miles on it - still got over 50 mpg when we traded it in.

A cool garage is of course preferred - but I don't believe a hot garage is going to cause you big problems - many hybrids are parked outside with windows rolled up and the hot sun beating down on them during the day.

 

Not to be argumentative, what’s the source of that, temp that hybrid battery fan starts up, or?

for a personal data point: when I was using a ScanGauge II (discontinued, it’s constant weight on OBD port was apparently triggering alarms), I distinctly remember an evening drive, ambient temp 35C (coincidentally 95F), and fan speed “2”. There’s maybe five speeds, with “1” being slowest.

FWIW, when the car’s on at least, at 95F active fan cooling was deemed necessary.

my garage ventilation project was mostly motivated by a freezer install, but I did have concerns for some years regarding our Prius with hybrid battery. Perfect storm is summer afternoons, parking hot car after a drive, and shutting all the doors, it would get like slow-death in there.

As a renter, I’d consider incremental, easily reversible measures at the least, in hot weather. Say: leave garage doors open a few minutes, pop and raise the hood (accelerates engine cool-down “some”), window fan if practical.

 

You're overthinking the battery......but to break with tradition and actually answer the question:
Attic fan.
A small one will fit into the window unless you live somewhere that encourages security bars instead.

The Home owner or realter may split the cost with you for having one installed - or you can do what my favorite USN Admiral would to to....um.....'debug the issue' and ask for forgiveness later.
Also, if you have a freezer or fridge running in the garage consider relocating it.


Best of luck!