If you’ve been using Zonai items in your Tears of the Kingdom creations, you’re undoubtedly familiar with the battery icon representing your Energy Cell’s power. You’re also probably familiar with how quickly it whittles down to nothing, sending your fan-powered planes crashing down to the Hyrule surface. If you want to increase your power output, you can do that, but you’ll have to brave the Depths underneath Hyrule to do it in the most time and resource-efficient way.
How do you upgrade your Energy Cell in Tears of the Kingdom?
To upgrade your energy cell’s power, you’ll have to find the Crystal Refineries, but to get the supplies needed to upgrade them, you’ll have to find the Forge Constructs. Here, Zonai robots will offer services tied to Zonaite and the Crystalized Charges you’ll find throughout Hyrule. At the Forge Constructs, you can trade Zonaite for Crystalized Charges, which can be converted into additional power for your Energy Cell by Crystal Refineries. To upgrade this bad boy, you’ll need 100 Crystalized Charges. These can be acquired by trading Zonaite found by defeating enemies in the Depths who carry it like the Bokoblin, or by mining it from black rock formations you’ll also find in the underground.
There are some other means of pocketing Crystalized Charges, such as being gifted them during quest lines like A Mystery in the Depths, but the easiest way to farm the stuff is to spend a lot of time in the Depths and trade for them with a Forge Construct.
Where is a Forge Construct or Crystal Refinery?
There are a few Crystal Refinieries in Tears of the Kingdom, but the most immediately accessible one is on the Great Sky Island in the southern area. If you fast-travel to Nachoyah Shrine, you’ll spawn right next to an early Crystal Refinery, but it lacks some of the same services as the ones you’ll find in the Forge Constructs in the Depths. There’s also a Forge Construct on the same part of Sky Island, which is accessible through a cave system beneath Nachoyah Shrine. Just jump down (and use your Paraglider to land safely) off the east cliff right outside the Mining Cave entrance and you’ll see a cave entrance that links to the Forge Construct. Here, you’ll be able to trade some Zonaite for Crystalized Charges.
While those are more easily accessible, there are several of these establishments throughout Hyrule’s underground with more abundant Crystalized Charges in stock. The easiest one to find is one you’re guided to in a quest. If you do the Mystery in the Depths quest (which begins in Lookout Landing), you follow a series of statues throughout the Depths in order to track down the final Ultrahand ability in the game. This quest line takes you to a Forge Construct, and you can transport yourself to it via fast travel. It’s just below the Great Plateau’s place on the land map.
What do I do when they run out of Crystalized Charges?
If you’ve stocked up on a lot of Zonaite, you’ll likely buy out the Forge Construct pretty quickly. It will restock periodically, so your best bet is to just go do something else and then come back. Whether that be mining more Zonaite or doing a different quest, you can’t seem to manually restock the Forge Construct’s Crystalized Charges without killing some time. Also, try rotating between different Crystalized Charges sources. If one place has run out, try one of the others. Don’t spend all your Zonaite in the same place.