Hi there are a few games I WANT to replace the battery for and a couple I NEED to the questions are what do I need to be able to replace the battery
what type of battery should I replace it with and where do I get it?
The games are:

-Pokemon Gold
-Pokemon Gold (2)
-Pokemon Silver (Will probably die very shortly if it hasn't this past month)

Quotes wiki "A common problem found in the second generation of games is a problem with the internal battery after roughly six years. The internal battery is located inside of the cartridge which allows the game to save the user's progress. Many people have reported that their games no longer save due to this problem, and any save file that remains before 2006 will be deleted.

It is possible to fix this, but the cartridge must be opened and the battery must be taken out, and a new battery must be soldered in. The battery model is model CR2025, although a larger CR2032 fits as well and will last longer. An inexpensive replacement battery can be purchased with the same welded tabs and insulating ring already attached such as the Panasonic BSG series (part # BR2032-1F2) available from Digikey. One will need to be able to use a soldering iron to remove the old battery and install the new one. One should get a battery with welded tabs such as the one mentioned above; it is difficult and unsafe to solder directly to a lithium battery without tabs.

With a new battery, the game's save file lasts a much longer time; however, any previous data saved on the game when the battery is replaced is lost."

but they just say second gen. (This is from the G/S article) they don't say
anything about it in the Crystal article so is Crystal okay? and I can't find the batteries on ebay either

-Pokemon Red (Hasn't died but I plan to temporarily transfer my pkmn to another game file then replace the battery and trade them back to my new file since whats left'll be gone after battery is replaced) I got all 150 (and three mews)
WITHOUT a cheat device (got the mews by using the Mew trick on a different file caught it transfered to Red game new gamed other file and redid etc.)
so I wanna make sure it can last a long time