Can I Use a Jump Box to Charge a Car Battery?

My car battery died and I never drive it around enough for it to build up a good charge, so I keep having to jump start it using my jump box.

Would it be okay to plug the jump box into the wall with the positive and negative terminals connected to the car battery (out of the car) to charge the battery?

Not a good idea, because those are designed to give the battery everything they have. What you need is a trickle or maintenance charger, to keep the battery topped-off.