Originally posted by: Nesmaniac
I would just buy good name brand CR2032 batteries & either wired holders (or if you want to spend a bit more time board mount holders) I've recently went through about 20 copies of Zelda's some that date back to 87 & all but 2 had saved data and the 2 that didn't I think were just empty to begin with. I don't recommend buying cheap ones because I can say that the sunbeam ones from dollar tree don't last near as long in my wii fit meter & their expiration date is like 5 years less than the energizers I bought at walmart. 2 pack of energizers were like $4.50 ish. I'd prefer panasonic, maxell, sony, or duracell but all wally world had was energizers & I was switching out batts in zelda 1 and 2 so I wanted to go ahead & get a couple. You probably saw my post of changing them using 2 different methods & even retaining my save. Really simple. I wish someone would make something that would go between the NES & cartridge (think Action Replay which I have one but never tried since it won't fit nes without modifying) that would have save points using modern components that are reliable & based off flash memory. I can't believe it's not been done since I know the tech to do so was around all the way back in the early 90's with action replay.
There are options on several platforms:
Retrode
Hyperkin Retron5
INL Kazoo (well, I know it can dump the ROMs at least)
Far Front East Super Wildcard DX2
Bung Game Doctor SF7 (and earlier)
Naki Game Saver+ (tricky but possible)
Bung PCjr (use with NES to Famicom adapter?)
Mr. Backup Z64
Bung V64
Bung V64jr
Super UFO CD64
GameShark/Action Replay + ProCom or whatever PC cable/card they used
GameShark Pro/Action Replay Pro + Dex Drive and/or parallel port cable
Bung GB Xchanger
GB Transferrer
...about a million GBA flash linkers
Definitely have a few options for different platforms with battery saves.