From the latest (v1.4) manual for the PP outdoor:
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• The battery can be installed against a flat wall, but the weight of the battery should not be fully supported by the wall. To help with this requirement, the battery comes with pre-installed feet that should be used to allow some of the weight of the battery to rest on the ground.
• If the battery is installed against a wall, EG4 insists the wall to be made of non-combustible material. If this is not possible, then the unit MUST have a minimum of 2 in. (50.8mm) of clearance from the wall to prevent heat transfer to the wall surface. Also note that whatever mounting solution that is used to grant the 2 in. clearance from the wall MUST be a non-combustible material.
• If installing on flat ground as a standalone unit, ensure there is proper drainage on the ground surrounding the battery to maintain integrity of the module over time and prevent damage from flooding. If installing against a wall, ensure at least a 12 in. gap on each side of the unit for adequate airflow and operations.
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Check the latest PP Indoor manual to see what it says, but there’s clearly enough ambiguity above to throw the final decision on the AHJ.
