Before you crack open a cartridge with a soldering iron, it's worth knowing whether you actually need to. Battery replacement is the right fix for some GBA save problems and completely irrelevant for others. This guide covers both — what the battery does, how to tell if yours is dead, and how to replace it without destroying your save.

Which GBA Games Use a Battery and Why

GBA cartridges that use SRAM for saves require a battery to keep that memory alive when the cartridge isn't powered. SRAM is volatile — cut the power and the data is gone. A small coin cell soldered onto the PCB provides a trickle of current to maintain the save data when the cartridge is sitting in a drawer.

Games that use SRAM saves and therefore have a battery:

• The Legend of Zelda: A Link to the Past / Four Swords
• The Legend of Zelda: The Minish Cap
• Classic NES Series games (most of them)
• Various third-party titles that shipped with SRAM chips

Most GBA games use Flash memory for saves, which is non-volatile — it retains data without power and therefore doesn't need a battery at all.

The Pokémon Battery Situation

Pokémon games on GBA (FireRed, LeafGreen, Ruby, Sapphire, Emerald) use Flash memory for the main save file. The battery in these cartridges powers the real-time clock (RTC) chip — not the save data.

When the RTC battery dies, you get the infamous message:

"The internal battery has run dry. The game can be played. However, clock-based events will no longer occur."

This means: berry growth won't trigger, the lottery won't reset daily, and other time-based features stop working. Your main save file is completely unaffected. The save is on Flash memory and doesn't care about the battery.

A lot of people replace their Pokémon battery thinking it will fix save corruption or a missing save file. It won't. If your Pokémon save is gone, the Flash chip has failed — a battery swap won't recover it.

The short version: replace the Pokémon battery if you want time-based events to work again. Don't bother if the save itself is your concern.

Signs Your Battery Is Actually Dead

For SRAM-based games (Zelda, etc.):

• Save data is erased every time the cartridge loses power (pull it from the GBA and the save is gone on next boot)
• The game boots but shows no existing save files despite having saved previously
• The cartridge is old — CR1616 cells typically last 10–20 years, so original batteries in GBA carts are approaching or past end of life

For Pokémon / RTC-only batteries:

• The "internal battery has run dry" message appears at boot
• Berry plants never grow
• Time-based encounters and events have stopped occurring

Battery Types Used in GBA Cartridges

Most GBA cartridges use a CR1616 coin cell. A smaller number use a CR2025. If you're not sure which your cart uses, open it up and look — the battery type is printed on the cell itself.

The critical detail: you need a tabbed variant for soldering. Standard CR1616 and CR2025 cells sold in blister packs at pharmacies don't have solder tabs. You need cells that come with metal tabs pre-welded to the positive and negative faces. Search specifically for "CR1616 tabbed" or "CR1616 solder tab" when ordering.

Soldering directly to an unmodified coin cell is dangerous — coin cells can rupture or vent under heat.

Tools Required

• Tri-wing screwdriver (Y0) — GBA cartridges use tri-wing screws, not Phillips. A standard screwdriver set won't work. A Y0 tri-wing is the correct size; Y1 is too large.
• Soldering iron — a temperature-controlled iron is ideal. 320–350°C works well for the tabs. A basic fixed-temperature iron works but gives you less control.
• Solder — 60/40 or 63/37 rosin-core works fine. Lead-free solder requires higher temperatures and is harder to work with for a small job like this.
• Flux — liquid or paste flux makes the solder flow properly and prevents cold joints. Not strictly required but makes the job cleaner.
• Isopropyl alcohol (90%+ IPA) — for cleaning flux residue after soldering.
• Replacement tabbed battery — the correct type for your cartridge (CR1616 tabbed in most cases).
• Cotton swabs or a small brush — for applying flux and cleaning.

Optional but useful: a phone camera or a loupe to read battery polarity markings clearly before you desolder.

Step-by-Step Replacement

1. Open the Cartridge

Use the Y0 tri-wing screwdriver to remove the single screw on the back of the cartridge. The shell should come apart easily after that. Set the PCB aside on a clean surface.

2. Photograph Battery Orientation Before Touching Anything

This is not optional. The battery has a positive face (usually marked with a + and the cell type) and a negative face. The PCB also has polarity markings. Photograph both from a close distance before applying any heat. Reversing polarity when you solder the new battery will prevent it from working and could potentially damage the PCB over time.

3. Desolder the Old Battery

Apply a small amount of flux to each tab connection point. Heat each tab joint with the iron until the solder flows, then gently lift the battery away. Don't yank — if one tab releases before the other, you could damage the pad. Work each tab alternately until the battery lifts free.

If the solder is stubborn, a solder sucker or desoldering braid can help clear the pads before you attach the new battery.

4. Understand That the Save Is Now at Risk

The moment the old battery loses contact with the PCB and before the new battery makes contact, the SRAM loses power. For an SRAM-based game, this will erase your save data.

If preserving save data matters to you, read the hot-swap section below before you desolder anything.

For Pokémon / RTC-only carts: the RTC chip losing power briefly is not a problem — it just means the clock resets. Your save file is unaffected.

5. Solder the New Tabbed Battery

Place the new tabbed battery in the same position as the old one, matching the polarity you photographed. The tabs should overlap the pads on the PCB.

Apply flux to the tabs, then touch the iron briefly to each tab where it contacts the pad. The solder should flow and form a clean joint. You're not applying a lot of heat here — the tabs are thin and the PCB traces are small. A couple of seconds per joint is plenty.

Don't press down hard on the battery with the iron. The goal is to heat the tab and pad, not to squash the cell.

6. Clean with IPA

Flux residue is mildly corrosive over the long term. Use a cotton swab dampened with isopropyl alcohol to clean around the solder joints. Let it evaporate fully before reassembling.

7. Reassemble

Place the PCB back in the shell, align the two halves, and reinstall the tri-wing screw. Don't overtighten — the plastic threads strip easily.

Boot the game and verify the battery works. For SRAM games, create a new save and check that it persists after removing the cartridge from the GBA for a few minutes. For Pokémon, the "internal battery has run dry" message should no longer appear.

Advanced: Hot-Swap to Preserve Save Data

If you want to replace a battery in an SRAM-based game without losing the save, you need to keep the SRAM powered continuously throughout the swap. The technique is straightforward but requires steady hands:

1. Strip the ends of two short lengths of wire.
2. While the old battery is still in place, hold the two wires against the positive and negative terminals of the old battery, then tape them in position so they maintain contact.
3. Connect the other ends of the wires to a fresh battery (same voltage — 3V), maintaining continuous power to the SRAM circuit.
4. Now desolder the old battery while the backup cell powers the circuit through the wires.
5. Quickly solder the new tabbed battery to the PCB.
6. Remove the backup wires.

The SRAM stayed powered throughout, so the save data survives. It's fiddly, but it works. A helping-hands tool or a second person holding the backup battery makes this significantly easier.

Alternative: FRAM Mod

If you want a permanent solution that never needs a battery again, a Ferroelectric RAM (FRAM) mod replaces the SRAM chip with one that retains data without power. FRAM is non-volatile — it keeps data even with no power source, the way Flash memory does.

This is a more involved soldering job (chip-level replacement rather than a single battery) and requires sourcing a compatible FRAM chip. The full guide covers this in more detail if you want to go that route.

If You Have a Repro Cartridge

Reproduction cartridges are a different situation. Most repro carts do have a battery and SRAM, but if your saves aren't persisting or behaving correctly, the battery is usually not the problem. Repro carts frequently ship with the wrong save type configuration — the ROM expects Flash saves but the cart's SRAM isn't being mapped correctly by the ROM's save code.

The fix for repro cart saves is an SRAM patch applied to the ROM before it's flashed, not a battery swap. Replacing the battery in a repro that has a save type mismatch will have no effect on the save problem.

See our guide on fixing GBA repro cart saves with SRAM patching for the correct approach.

Battery replacement is a legitimate repair for original GBA cartridges with genuinely dead cells. For SRAM games, it's the difference between a working save and losing your game every time you put the cart down. For Pokémon specifically, it's optional quality-of-life unless you care about berry farming or time-based events. Either way, with the right tools and a photograph of the polarity, it's a 20-minute job.