Crystallized Charges are an item from The Legend of Zelda: Tears of the Kingdom. They are able to be purchased using Zonaite from some of the game's vendors, many of which are located at the various mines in the Depths.
You will need to progress through the game to find the right chasm leading into the depths, as well as defeat one of the game's many boss enemies, before you can buy anything. Once all the conditions are met, you will be able to return to The Great Abandoned Central Mine whenever you find yourself in need of Crystallized Charges.
Updated by Chad Thesen on July 29, 2023: This guide has been updated to feature new embedded links that can allow easier navigation for readers. These embedded links include one for a guide for one of the game's many lightroots, as well as a guide for using the Zonai dispenser to have many of the parts you may want at various points in the game.
Great Plateau North Chasm
On the map, look to the south of the Hyrule Field Skyview Tower in Hyrule Fields and zoom in. You should see Lake Kolomo on your map, and below this lake will be the Gatepost Town Ruins. Southwest of these ruins will be a chasm you can jump down. You will see the “Great Plateau North Chasm” when you approach it while traversing in the game.
Great Abandoned Central Mine
Once you have made your way down the chasm, you will see a room with one of the game's Lightroots. Passing through this room and heading straight will lead you to the Great Abandoned Central Mine. This location will be listed southwest from where you dropped on your map with several markers.
Defeating Master Kohga
Before you can get any Crystallized Charges from here, you will need to defeat this boss. This boss appears several times in the game. If you have had fun making all sorts of vehicles using the game's Fusion System. This is one of the many Zonai abilities you will be able to play around with. This will put you on the opposite end of every enemy you have driven over in the game, as Master Kohga will come at you with a vehicle of their own.
To defeat him, you will just need to dodge his vehicle, shoot arrows to knock him off, and then use your best weapon to deal damage while he is on the ground. Later in the fight, his vehicle will become a lot more sturdy, you will need to lure him into hitting a wall when he charges, then climb up to deal damage.
Using The Forge
Inside The Great Abandoned Central Mine will be lots of shelves with Crystallized Charges. Approaching one of these shelves will begin an interaction with the vendors about how many you would like to buy. Be sure to have enough Zonaite when you arrive.
Increasing Energy Wells
You can use these Crystallized Charges to increase the number of batteries displayed while using the many kinds of Zonai devices you will create along your journey.