I recently purchased a used 2015 Pro-4X. It has the power inverter. I am an idiot when it comes to electricity and the owner's manual is useless in regard to how to use it. So my question here isn't technical. Just wondering what this is useful for and what it isn't useful for. I'm assuming I could charge my cordless tools with it (with engine running) but not run a circular saw, etc? Does that sound right?