Hard wiring OEM inverter to dual battery?

Is it possible to rewire the factory inverter so that it is powered independently, and still controlled by the dash switch? I am looking to power it from my aux battery instead of my starting battery (dual battery setup), so that it doesn't shut down when the vehicle is turned off. Yes, I understand it's a large load on the battery, and I don't intend to run it with a large load for extended periods off time with the vehicle off. But I would prefer that it doesn't shut down if you were to shut the truck off for a few moments to run inside a store or something.

I searched the forum and I found numerous threads about the "anytime 400 watt" mod, but nothing about hardwiring it directly to a secondary power source in order to keep it powered with the ignition off. Just wondering if anyone has any experience. Thanks!

 

to this:

 

Thank you @caribe makaira

 

You'll need to do the 400 always mod also.

 

Did you ever get this set up? Thinking about doing it myself and wondering if there's any feedback/pointers you may have.

 

Sadly, I did not ever get around to completing this. I started to look into it, and then got too worried that the draw from the inverter (in use) will kill my aux battery while the engine is off, and that it's better to just use it while the engine is running.