Long story short, a bottle of wine popped open in my trunk. Went on to clean the flood, only to find severe corrosion under the battery.



Looks like water has been collecting in there for quite some time (besides being under a battery with all battery acid related issues). Plan is to wire-brush it as clean as possible, rust convert, etch primer and paint it. However, I would like to prevent this happening again. I have already ordered the removable tray (mine was missing), and I also came across this that supposedly helps with battery acid (although I am worried about trapping moisture)

https://www.batterymart.com/p-battery-mat-black.html

However, my question is, are there any factory water drains in there? Being behind the wheel well, I can see why possibly not; on the other hand, being a low point behind leaky tail lights, it should.