Why does my Pokémon Gold cartridge seem to forget saved gameplay?

I recently bought a copy of Pokémon gold version at a car boot sale. I played it for a while but then I had to stop, so I saved and then turned the game boy off, and took the game out. The next day when I put it back in my Game Boy and switched it on, all my save data was gone and the only options were New Game and Cancel.

I checked online to see if it was fake, but it looked the same as all the real ones. I also compared it to my Pokémon red which I know is genuine, and all the details of the cartridge were the same (except for colour and sticker of course) here are some pictures of the comparison between the two games

Does anyone know whether this copy of Gold IS fake? How can I tell? Or is it just broken?

Solution 1:

The memory card in Game Boy games needs power to run. It contains a small battery to do this when it's not in a Game Boy.

Pokemon Gold was released 15 years ago. The cartridge is very old and the battery has run out. This means that the memory card cannot hold data unless it is actively being powered (which somewhat defeats the point of saving the game).

It is possible to change the battery. Here's a guide on how to do it. It's worth noting that the type of battery the Pokemon Gold cartridge uses is a model 'CR2025' battery.

If you are not comfortable with changing the battery yourself, many stores, especially those focused on retro or vintage video games, are capable of replacing the battery for a nominal fee