That's strange. Manuals should have sealed off batteries although I have seen a few that have open batteries. It depends on where the hole that you're talking about is, though. I don't know whether you're talking about a hole beside the threads or the very center of the battery where you could stick a paperclip in and touch the actual battery... Either way, I don't like unsealed batteries because juice can get in there too easily and F up the battery really quick. If you're talking about a hole right next to the threads, that's for ease of draw.
Well, the manuals really are sealed, I think that even though there is a hole in the manuals, that the battery itself is sealed with slicon or silicone, I can't remember which. It was silisomething heheh

, but I really think it's just a vestigual hole in my batteries

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I think it's supposed to be a very thin sealing layer tho, but yes Xanax, I was referring to the centerpost hole.
I wonder if it helps anything. Could it help keep the juice away from the centerpost surface itself so as to try to keep the centerpost contacts as dry as possible perhaps?