Wes
I went to ask.com to see any results and it is a myth. Here is the explanation that I found. Hope it helps.
Q: Is it true that concrete will drain batteries left sitting on it?
A: No. This myth had validity back when batteries used glass separators between the lead plates. Then, if you dropped the battery on a concrete floor, the glass separators cracked or broke, thus violating the solid barrier between the plates. That allowed the positively (+) and negatively (-) charged lead plates to touch and the charge leaked off through the connection.
Therefore, people thought that "concrete caused the battery to discharge when, in fact, it had nothing to do with it," says EverStart Batteries of Wal-Mart Stores.
Today?s batteries use paper (instead of glass) envelope separators to keep the (+) and (-) plates from touching. The paper separators are highly unlikely to tear even if you drop the battery on concrete.