Additional fee by weight

Hey!

I live in Norway, and we are obligated by the state to add a specific fee for certain products, for example we have a environment fee for batteries. Lets say its 0.6$ per kg.

I’m trying to add this fee only to batteries. And for the site to calculate the total fee based on the battery’s weight.

To simplify; Lets say i have a 3kg battery, then I want woocommerce to multiply the fee and the weight itself. 3 * 0.6 = 1.8$.

I’m also trying to make this fee showing up on the checkout area, so the customer can see the fee themself.

Been trying for 3 days, and nothing. Can’t find any plugin that supports this, and i don’t know how to make this work.