Thanks Rob. It is good to know what product was used. It looks like coal tar epoxy is available from a few different manufacturers including Rustoleum
http://www.rustoleum.com/product-cat...coal-tar-epoxy
However, it is only available in 1 gallon cans and larger. The coating in my battery box is still quite good, so I will not redo it at this time. I was kind of hoping to find something in a spray can that I could do a minor touch-up with.
Ill save the complete recoating job for a future time.