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.