xon wrote:Ironically there are some theoretical designs for non-thermal nuclear batteries which amount to using a photovoltaic cell wrapped around a radioactive source with a mediam which converts beta radiation into light.
Got a link? I'm intrigued by this.
I apologise profusely if I'm underestimating your physics knowledge here, and what you're actually asking for is information on actual designs of batteries like this, but the concept itself is fairly simple - hell, I have right now, attached to my keyring, effectively half of such a device.
All you really need is to take some transparent material, the stronger and more transparent the better (graphene would come to mind here . . . ) and then coat the inside with a scintillator, then fill it with as much tritium (radioactive isotope of hydrogen) as you can without it rupturing. You then surround this with a photovoltaic cell, presumably tailored to the product of your scintillator's emission spectrum with your case-material's absorption spectrum (i.e. if your case absorbs a load of ultraviolet light, you want to use a PVD that will absorb more lower-energy light to maximise efficiency). Once you have this, bam, constant power for a long while. Tritium has a half life of ~10 years, so you may want to use something that'll last longer, but it illustrates the principle.
As I mentioned earlier, I have half of such a device in my pocket - a little resin case containing tritium and scintillation material. Helps find keys in the dark!
Just to not be completely off topic, it seems there's two camps in this thread; those who like an armour progression leading to Power Armour being practically required in the end-game, and those who want your choice of armour to be an important factor tactically.
I don't see any reason why you can't have both - as people have mentioned, have a range of armours at each 'stage' of the game. At the start, maybe you're choosing between solid metal plates bolted together to clank around and soak up bullets, or hardened leather/suppler materials for stealth/ambush based tactics. Later on you'd be choosing between military-grade combat armour and perhaps some kind of kevlar-or-similar based infiltration gear. High end, there's no reason you can't have multiple grades of power armour, from the walking tank who becomes a bullet/plasma magnet, to the nimbler, thinner-but-still-heavy power armour with padded joins for noise suppression, and perhaps some kind of optics-based camouflage?
Essentially, multiple different 'trees' of armour progression depending on character archetype.