So when looking at things like Security Robots, or Ahavs, are they like golems in that they have functionally endless operation times? Do they have their own reactors or other form of long term battery storage? I mean apparently for things like Sec bots, they can have things like infinite breath weapons (jolt arc every 1d4 rounds) and assuming they aren't destroyed 'fast slow healing of CR per hour' for hitpoints.
Statbox wise they then get listed with things like 'weapon + 2 batteries" but their own 'jolt' not taking any battery requirement. The AHAV listed has ammo using weapons but we don't see any 'lasgun' variants to compare with.
The question i'd draw would then be, "if they can do this otherwise with no real time limit or power draw, can they recharge their own weapon batteries?"
But if you can have bots that do it..I could see a problem in that there's no reason people in power-armor couldn't do it too. Attach a bot-level power pack to your power armor and it now recovers more charge per round or unit time that it expends and can recharge its own weapons.
I've always figured robots have an internal battery as well as several methods for generating power. Either by connecting to charging stations within the facilities where they operate or even being solar or nuclear powered. The power packs may take up too much space within the robots overall fuselage to be co-opted for other reasons.
Power armor has to not only move but has to fit a person inside it. That space where the person is likely where the super-awesome-robot power sources are in an equally sized robot.
I can see this for Sec-bots intended for limited areas. AHAVs tho, warbots, maybe they run mini-nukes? They seem big enough.
Using thermoelectrics and nuclear fissable material you can have a very effective small scale generator without very much complication and that is with today's technology and no magic. It's very easy to believe that you could have something like this in every robot in starfinder. It is also telling that SROs from the pact worlds don't need a power source, but do need to "rest" 8 hours each day. You could flavor this as a time to recharge internal batteries from a low output generator.