Originally Posted by
Blitzwing256
its been my expereince that a game will generally hold the saves for about a half hour without the battery.
(tested this with a batteryless ultima exodus) the chip will retain the charge for about 2-30 minutes without a battery attached, so in theory if you're swift you can retain your saves (again only done this with the nes but I assume other systems are the same)
another good option is to get a snes copier and back up your save ram (some of them are capable of this) so you don't run the risk of losing it.