The fumes from batteries will corrode metal. And
battery boxes should have a venting system.
As for the inverter, it needs to be well ventilated, especially if it'll be used often. Follow the instruction book for
installation, especially the wire size. If anything, go up one size for full efficiency.
And install it well above the waterline. Mine was set up to run a submersible
pump for dewatering, just in case.
Is it a 'true sine' wave? Some
electronics will not run properly unless it is.