The pokemon sapphire game for game boy advance has an internal battery. If this battery runs down, you lose certain features of the game and you will get messages on the screen complaining of a dead battery. The battery is not really meant to be a user replaceable item but if you have a soldering iron and a little soldering experience it isn't too bad. Do be aware though that you have to be a little careful as you can damage the game. If you have worked on circuit boards before it isn't bad but if not, you may wish to practice soldering and desoldering a little on something else first. Please note that one reader has commented "you can lose your save data". I do not have sufficient data to confirm or deny that so I'm putting it out there as a warning. I am not sure if the data is saved in flash memory or if it relies on the battery fully to preserve the save data.

You will need:

- tri-wing screwdriver for removing the cover
- CR1616 replacement battery with solder tabs (Batteries Plus carries the battery and will put the solder tabs on for you). Note, it appears that amazon also now carries CR1616 with the tabs on it already.
- soldering iron and a small amount of electrical use (NOT plumbing use) solder
- desoldering wick
- tweezers, needle nose pliers, or a toothpick
- old scissors (you will trim some thin metal so leave your sewing scissors in your sewing table!)

Step 1: Remove Cover

Before starting on this step you should find a good place to work. Solder contains lead and as such a kitchen or dining room table really is not appropriate. Also there is some concern over static electricity. If you have an anti-static electronics workbench that is the best. However most people don't have this in their house. I don't and I work in electronics.... I just work on an old plywood top work bench in the basement but I don't pet my cat at the same time (or do other things which would generate a lot of static electricity).

To remove the cover you will find you need a special screwdriver. I used this screwdriver http://www.amazon.com/gp/product/B000S6AG9G from amazon. If that link doesn't make it search for "Tri-wing Screwdriver for Nintendo Wii, Gamecube, Gameboy Advance". I paid about $5 for it.

Cover removal is simple. First take out the screw and then slide the back up relative to the front and they will easily lift apart. You do not need to pry anything. The second picture shows the back and front slid relative to each other.

Step 2: Desolder the Battery

To perform the next step, you should first lift the circuit board out of the plastic case to avoid melting it. Then desolder the battery. What I did was to take some metal tweezers that are dedicated to electronics use in my shop and apply gentle upward pressure on the far right battery terminal while heating the solder joint with the soldering iron. Once the solder melts that battery tab will lift right off. The key is gentle lifting here because you don't want to pull the board apart by pulling hard before the solder melts. If you don't have tweezers, you can use a toothpick to lift.

After the first corner is desoldered, heat the 2nd joint with the soldering iron and when the solder melts, just lift the battery off. Again, I used tweezers. Needlenose pliers are also appropriate tools and if you don't have either, you can use your toothpick again.

Note that the top of the battery is labeled as the "-" (minus) terminal and goes to the upper right pad on the board.

Step 3: Prepare the New Battery

The battery is a CR1616. These are fairly common place. The trick is that in this game cart the battery has 2 solder tabs which have been spot welded on. You really don't want to try and solder directly to the battery (due to the heat and questionable ability to make a decent solder joint anyway). Also you probably don't have a spot welder in your basement. I know I don't. Luckily I found that my local Batteries Plus store was able to add the solder strips for me. If you don't have that store locally, I'd suggest looking at a hobby shop or other dedicated battery store. You may be able to get this online from Batteries Plus. I'm guessing you'd have to call them for it.

The solder tabs (strips of metal) that the battery shop spot welded on for me were fatter than the originals and not shaped the same. It was fairly easy to trim them to size using some scissors for trimming and needle nose pliers for shaping. Also you will want to add a small piece of electrical tape on the right hand edge of the battery to make sure that the top tab won't ever short to the edge of the battery.

Step 4: Prepare the Circuit Board

There are likely blobs (that is the technical term) of solder left on the pads where the old battery was. These should be cleaned up. The right way to do it is use some desoldering braid (also known as desoldering wick). This is some thin wires woven together usually with a chemical in it and when you place it on the solder blob and heat with the tip of the soldering iron it will wick up the solder. You can by the wick at any electronics store and probably also your local Radio Shack. You don't need super clean, just wick up the bulk of it. Also you don't want to keep the iron on the board for a long time or you can soften up the adhesive which holds the copper pad on the board. An appropriate amount of time is just a few seconds (2 or so) after the solder begins to flow.

Step 5: Solder Down the New Battery

Being very careful to not let the battery leads touch other parts of the circuit board (they may not appreciate it), set the battery in place. Carefully solder each of the two joints. After soldering the first joint, wait a bit for it to cool before soldering the second. The reason for the wait is so that you don't disturb the first during cooling which would compromise it somewhat.

After soldering down the battery, there will be some rosin (a.k.a. flux) left on the board near the solder joint. That is the darker gunk in the picture. This should be cleaned off. Some solders use a water washable flux. I used a Q-tip dipped in rubbing alcohol (90% isopropol alcohol) and scrubbed lightly. Make sure you let it dry, however you clean it.

Put the board back in the case, put the lid back on, slide it into place, and put the screw back being careful to not strip the plastic threads.

All done!

In Pokemon Sapphire the way you can tell it worked is the "internal battery has run dry" message no longer appears when you start the game.