Yeah, without a large power source it’s very impractical, if you’re lucky you can get a bunch of UPS items and double their power. Or using the CBM for them, which is a bit more feasible, a few passive power sources and something like an Ethanol Burner or Internal Furnace would allow you to use it for longer periods.
But finding or making enough power upgrades to sustain it without running into town drop-dead drunk or weighed down from wood would be quite a feat, and a Metabolic Interchange would cause you to be eating almost constantly. The Internal Climate Control CBM accomplishes temperature control, and in the case of the first Power Armor Interface, is much more effective. However, if you can find light or heavy power armor, the CBM that interfaces with them is much more efficient.
Basically keep unpowered power armor off the body until you need it. It’s armor is just as effective without power, and if your skills are above 3, you should be fine.
