You don't need to use (take out) the chargers from the Inventory. The Inventory only lists them.

You use your chargers right from your Collections. Open your collections and see there's a box with chargers against each collection that shows the total of each type and the required number to complete a collection.

Simply tap the Assemble button against the collection that has enough chargers and all items found. The chargers will be used and recalculated automatically in your Inventory and against other collections that require this type of chargers.