I was going to blow this off as an old man tale, but really if the battery is in long term storage, say for the winter, and the concrete was cold, I suppose the battery would stay cooler due to conduction of its heat into the floor. The wooden block would have a slight insulating value and keep the battery temperature closer to the air temp in the area it’s stored. If you think that’s a good thing go ahead and put a wooden board underneath.
If I pull the battery out of the vehicle for some reason, I sit it on the concrete floor. If I plan on leaving the battery out of the vehicle for a long period of time, I will place it inside a container of some kind in case there is a leak of battery acid.
I dont believe the myth but does putting it on a board HURT anything.....
I put it on the block so its easier to pick up.. ever try picking up a battery off concrete floor with no handles? oh and extra props if you are 6'2" and have bad knee that pops out.
I stopped doing the wood block thing when I saw that they don’t go dead from it.
But I will long term store a battery (or several group 49 and 94) that I have on a shelf or pallet. Why? Because the concrete surface will scuff the h&ll out of the casing if it gets moved or shoved around a lot. Otherwise do what you want: there are no “Battery Police” to stop you.