it's a form of memory retention that utilizes a battery to power a RAM chip while the rest of the computer system is powered off.

Battery backed SRAM was popular in the 80’s and 90’s as a way to circumvent the fact that Mask ROMs used in video game cartridges aren’t rewritable. As early as 1994, new methods of video game data retention were introduced, and by 2004 or so, they’d completely stopped using it. Game Boy Advance for example, only has a few games that utilize it. Even going back to Nintendo 64, they weren’t exactly common. However, some extremely heavy hitters like Ocarina of Time and even Super Smash Bros. use them.

The NES started using it around the time the console was introduced in the United States, albeit sparingly. The console wasn't designed with this technology in mind, so games will often tell your to hold reset while powering off to prevent corruption.

Game Boy/Color and Super Nintendo Entertainment System utilized this method of data retention almost exclusively. If the game saves data, this is how. I can only think of one Game Boy Color game that doesn’t, and it’s Kirby’s Tilt & Tumble of all things.

the technologies reliance on batteries meant that any data saved has a lifespan tied directly to said batteries. When those batteries weaken and die, the data stored on the SRAM chip it's powering goes with it. Permanently.

If you’re a collector, or prefer using your cartridges over an Everdrive, you’ll need to know how to replace these batteries. The great thing is that it isn’t very difficult to do, and if you’re learning from scratch, you’ll learn a new skill that’ll benefit you in ways that’ll only become apparent later on.

These are all off the shelf 3 volt coin cell batteries. Nothing about these components are proprietary. Hell, you can install a battery holder in your game and put a battery you bought at Walgreens in it if you'd like.

Between the various consoles discussed here, voltage is the same. They’ll often say 3.0v, but they read 3.29v to 3.34v on a multimeter. There’s nothing wrong there, and even under load, they’ll usually read well above 3.0v. That’s just the way it is with these SRAM circuits. The part number for the battery refers to diameter and thickness. That said, the larger the battery, the more draw it can handle, generally speaking.

Yes. Soldering is easy and fun. I don’t know why so many people view it as some kind of barrier. If you’re unsure where to start, Voultar makes incredible videos on Youtube, and I suggest you watch them. At the very least, will familiarize you with good techniques and what the final product should look like when you’re finished. Soldering, while easy, is a precise art that requires practice, kinda like riding a bike. You won't be good at it at first, but with practice and motivation, you’ll be set for life. Once you learn, you’ll never forget. It’s muscle memory in its purest form.

There is no scenario where you can perform a battery swap successfully without soldering. I’ve seen idiots try to brute force this by ripping the old battery out and using electrical tape to fasten the new one in. This is actually more difficult to do successfully than simply learning to solder and doing the process properly. You can easily damage games board doing this. If you refuse to do things properly, you have no hope of fixing the board you've damaged. Might as well not bother at all.

If you're looking to simplify the process, learn to solder, and install a battery holder in place of a tabbed battery. I don’t do this myself because I’d probably have more problems removing the battery from the holder than simply desoldering a tabbed battery. I'm telling you, once you learn, you'll never forget, and you'll ask yourself why you didn't learn sooner.

No. Don’t just put any random battery you buy off of Amazon into your game. You’re gonna realize fairly quickly that many of them are garbage, and won’t last anywhere near as long as the original did. I learned this lesson the hard way, multiple times, actually. I replaced the batteries in my copies of Wario Land and Tetris DX in 2016 and 2018 respectively. I’d used whatever cheap crap I could find, and those both needed to be replaced again in 2024. I have a copy of Super Mario Deluxe that had its new battery die in under two years. All of them had one thing in common, I’d used cheap, chinese batteries.

My copies of Link’s Awakening and Super Mario Land 2, both replaced in 2017, are still running to this day just fine. Removing and inspecting both batteries revealed I used Maxell and Panasonic batteries at the time. Readings taken off of them both under load and out of circuit show they’re pretty much perfect still. Meanwhile, the cheap Chinese batteries seem to have amperage issues so those of you looking solely at voltage will find your batteries failing while the voltage is still well within spec. It’s ridiculous that these things are failing like that, but I’m not surprised.

Cheap batteries will die within a couple years. look for Maxell or Panasonic batteries if you’re looking for actual longevity. If you’d like to use something like Duracell or Energizer, you can install a battery holder.

You’ll need the following to properly replace your cartridge's battery.

• Soldering Iron
• Solder Sucker or Desoldering Gun
• Solder and Flux
• Quality Battery
• Game Bit Screw Driver Set
• Your Game

The stuff linked above are all things I use or have used in the past. Yeah, it's expensive, but it'll all last you years and years.

If you’ve got the equipment on hand, back up whatever save file is still on the game cartridge. Once the original battery is removed, all save data will be lost.

1) Disassemble the cartridge, place the plastic casing, any shielding, and especially the screws in safe location. The front of the board wont always face the label side of the cartridge, so make note of how everything is oriented inside before you begin.

2) Test your new battery with a multimeter to ensure it’s good. Ideally, it’ll read somewhere between 3.29v and 3.34v.

3) Add fresh solder to the batteries solder joints. This'll help whet the solder holding the battery in place. Heat the solder joint and use your other hand to lift the battery out of place. Do the same for the other side.

4) Remove excess solder. If solder is stuck in a via, add fresh solder and suck it out.

5) LIGHTLY coat the battery tabs in flux and install the battery. Keep polarity in mind. Your joint should be shiny and smooth; never jagged. Don't blow on it, you'll oxidize it.

6) Gently pull the battery to ensure you're properly installed and test battery with multimeter one more time.

7) Put it all back together.

Always keep in mind where your iron is while it's on. You'll hurt yourself or break something if you don't. Don't touch it to test for heat.

NEVER touch the coin cell with your iron.

Be mindful of surrounding components and traces. This is especially true of Game Boy and Game Boy Advance. The shaft of your soldering iron is just as hot as the tip. You will destroy things if you're not careful.

Most solder has built in flux. You may read that and think "I don't need flux". Yes, you do. Always use it, but never in excess.

Take your time and be patient. If you try to rush things, you'll break something.

You can buy replacement batteries for your NES cart through this link Console5 is a wonderful resource and I've been purchasing parts from them for years.

before you do anything, check the list of games that utilize SRAM saves. Most games in this era used passwords, tape decks, or other crazy crap.

Games in the NES Programmable Series do not utilize a battery to save. They were meant to be used with a tape drive that was never released here. There are ways to reintroduce that functionality to the NES, but they're a pain in the ass.

Some NES games have unpopulated battery sections on their board. No, putting a battery in there will not enable saving. Don't do it.

You can buy replacement batteries for your SNES cart through this link Once again, Console5 is a wonderful resource and I've been purchasing parts from them for years.

Super Nintendo games are more straightforward than NES games in terms of saves. Virtually every game that allows you to retain data between sessions will use battery backed SRAM.

For the Nintendo Power cart, games are stored with Flash memory, and only save files are lost when replacing the battery.

Use this battery For both your cartridges and any controller paks you have laying around.

There are several methods that N64 games will use to save data. Most games that save to cartridge will simply use EEPROM or FlashRAM, which don't require batteries. Check out this list to see if your game needs a battery swap.

Most third party N64 games utilize the Controller Pak for saving. The controller Pak does have a battery, and it will need to be replaced at some point. Better now than later.

Like the Genesis, if you're finding that your game has lost it's save file, clean it and reseat it before you consider the data truly gone. Chances are, it'll pop back up.

You can buy replacement batteries for your Genesis carts through this link Console5 is great, buy stuff from them. No, they aren't paying me to say this. I mean it.

There's a large list of Genesis games that use battery backed SRAM.

Several games like Sonic 3 use EEPROM chips for retaining save data. EEPROM is far more reliable than battery backed SRAM, but you can occassionally boot your game to see your data is gone. Reseat or clean the game, and it'll usually come back.

Sega CD Memory cart uses a CR2450. Get one here.

Batteries for Game Boy are all surface-mount. A battery for console games might work in a pinch, but I wouldn't rely on it.You can buy a battery for CR1616 games here, and a battery for CR2025 games here.

Games that use a CR2025 can safely be rigged up with a properly tabbed CR2032. Don't try to use a battery holder meant for CR2032, it'll almost certainly not fit once the cartridge is reassembled.

Be vigilant! Some games use a CR1616 battery. Others use a CR2025. You won't know which one you need until you open the game. Sometimes, a Game Boy Color revision of a game will use a different battery than the original Game Boy version. B&W Wario Land II uses a CR2025, while the color version uses a CR1616.

Pokemon Red, Blue, Gold, Silver, and Crystal all utilize a CR2025 battery. Pokemon Yellow uses a CR1616.

Some games utilize a real time clock or "RTC". This'll significantly reduce battery life, and when that battery does die, your entire save file will go with it. There are individual flash carts available that separate the RTC circuit from the save circuit. When the RTC battery dies, your save file will remain in tact. They're also compatible with Pokemon Stadium. Consider using these instead of paying a scalper big money for extremely common games just to have it die on you in five years and lose everything.

Most Game Boy Advance games save to flash memory. There's no reliable list of them. There are a lot of bootleg GBA games floating around. Be sure to check what the board should look like, and compare it with what you've got on hand before opting to replace any batteries you find. Replacing the battery in a bootleg is pointless. You can use a GB Operator to determine whether or not your game is authentic to save yourself time. If you're doing this kind of thing, you should have one anyway.

Pokemon Ruby, Sapphire and Emerald will not lose saved data if the battery inside dies. The battery is solely for powering the Real time Clock (RTC). When you replace your battery, you'll need to reset the RTC so that berries can grow again. Starting a brand new save file after a battery replacement will also reset the RTC so this is only necessary if you wanna continue with your old pre battery death save file.

Virtual Boy carts use a CR1616 battery just like the Game Boy.Get it here.

Please make note of how things are oriented so that you put everything back together properly.

If you use a good battery, then I’d presume several decades. Now, there are some caveats to consider. Games with Real Time Clock capabilities will last 5-10 years at best. Practically speaking, the less information the game saves, the longer the battery will last. The Legend of Zelda on NES will last longer than any Pokemon game. I think most of my copies still have original batteries in them. They’re almost 40 years old and still work fine. Zelda saves a few variables regarding what you do and do not possess. Pokemon though? Do I need to explain?

If you’re worried about it, install a battery holder.

Yeah, dump your game and run it in an emulator or flash cart. Remember, this is a hardware problem. NesterJ doesn't care that your copy of Kirby's Adventure doesn't hold a save. The biggest problem with this is the cost. You'll spend a pretty penny on dumping hardware for anything other than Game Boy. You could emulate the traditional way, but that completely defeats the purpose of owning the game to begin with. Just replace the battery and be done with it.