Trench torch - how to change the battery?

[Decapitare]

I have two batteries and a torch with (I assume) a dead battery now, but I can't seem to combine the two. What am I missing here?

[BudgieGaming]

You don't combine them, instead, with the torch equipped, you select the Insert option of the battery in the inventory.

[Decapitare]

Ah thank you very much.