The only way to use it 100% of the time is to get the CBM internal change (not sure of the name, maybe …), it allow gain power from hunger for a ridiculous number. Other way cost too much.
Power armor is inefficient about its fuel sources to say the least. Amazing stuff while powered, though.
Advanced power interface bionic plus joint torsion ratchet, metabolic interchange, and solar panels with lots of power storage makes it feasible for the short term but still impractical for constant use.
Best bet is to get as much of those things as you can and then drive to where you need it with the armor in your trunk. It makes you into a walking tank but it’s crap for overland treks.
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.
I put on power armor as soon as I find it and never take it off.
Heat is only a problem when you’re outside in the summer, but I’m in a vehicle or indoors 99% of the time.
Eventually I raid a couple of mansions for books and get electronics to 9 to craft the MKII interface (which also works with basic power armor) and then you can have it powered through metabolic interchange 24/7 at a cost of a couple of squirrels per day.
The key is to wear light power armor set (only 4 encumbrance, so you can travel while your armor if diengaged) and to use advanced UPS that lasts for ~5 hours with only 5 plutonium cells loaded.