Running a van's ac without the engine running without adding a roof unit

A friend of mine who is a very mechanically talented is talking about completely removing the belt driven compressor from his charger, replacing it with an electric compressor from an EV, moving it out of the engine bay to make room for other ridiculous mods and beefing up the alternator. A side effect of this mod is that if one were to add a storage battery grid to this setup and run the AC off the storage battery grid, wouldn't that be ideal for a camper van? His entire budget is less than the cost of a roof AC, not even including installation. What would be wrong with doing this same mod to my van? (he's willing to help)