Battery box from a Coleman ice chest?

Just my thoughts on this, based on my experiences, Alan.......you didn't mention what kind of inverter it is, but in my case, the inverter has relays for switching power, and yes, they do make sparks.  My inverter also has a cooling fan for battery charging in "low battery transfer" mode and needs open air to provide cooling.  The charge controller is the same.....has a heat sink and needs to vent for cooling the semiconductors in the controller.  I have my batteries in a semi-enclosed box with insulation on the wall side of the box, and find that the battery temperature is a more-or-less constant 60 degrees (live in a northern climate), since the batteries generate some heat of their own with chemical reaction, and internal resistance when working a load.  So, I am thinking that it is not a good idea to enclose the inverter in the box?  If you employ hydrate caps for the batteries or have the maintenance free type of battery, the hydrogen should be  contained and returned to the battery as water.  (All things in life are variable and subject to change...wink)