batteries - Would splicing existing wires (from charge controller to battery) to connect an inverter work, and is it safe?

I'm trying to add an inverter in my travel trailer, but wanted to figure out the best way to do it. Because I'm not that familiar with the electrical setup of the trailer, I was only able to access the electrical components of the charge controller; the rest are wired under the trailer somewhere.

I just want to know if it'd be safe to splice the wires going from the charge controller to the batteries, to hook up the inverter. I know that the ideal way to do this is go straight from the battery to the inverter, and not piggy back on any existing wiring; but the wires from the batteries all go under the trailer, and I'm not sure how it's all wired together.

Apologies for the amateur question(s).