Having been involved with the handling of this and other similar chemicals, I take safety seriously. I urge you to read the MSDS on any chemical you may use.
Here is one copy
http://rrworthogs.tripod.com/archives/percarbonate.pdf
In partcuar note....
Storage and Handling
• Store in a dry location away from heat and out of direct sunlight in containers fitted with a
safety valve or vent. Storage temperature: <104°F (40°C).
• Store in an area away from acids, bases, metals, metal salts, reducing agents, organic
materials or flammable substances.
• Never return unused product to the storage container.
• Rotate inventories - first in, first out.
I would urge you to store only a small quantity in a suitable container within the RV.