My GL-500i came with a broken long tab on the battery side cover. The tab was hanging by a thread. Someone had tried to repair it with some kind of rubber glue.
I cleaned it up, and repaired it with Permatex Ultra Black Rubber Seal. I use this for many repairs in automotive and around the house. Worked like a charm on my battery cover tab. Ran it all last year, took the battery cover on and off many times with no issues. The tab flexes a very little bit, but holds fast and firm.
Whatever works, works!