The Power Sources table lists the years of use for each power source, even those typically used to power discharged weapons. This gives us an approximate value of how much energy each power source contains. So going by this, we'd probably see options like this:
Power Source | Energy Weapon | Powerful Energy Weapon | Radiation Weapon |
Power Clip | 10 | 1 | 0 |
Power Beltpack | 25 | 2 | 1 |
Power Backpack | 50 | 5 | 2-3 |
Minifusion Cell | 80 | 10 | 10 |
Plutonium Clip | 160 | 10 | 10 |
Radioactive Battery | 330 | 40 | 20 |
NOTES:
1. Radioactive Battery is included mostly for S&G, but also because it gives a rough idea of how many shots androids, cyborgs, and robots would have available.
2. Energy Weapons refers to those weapons listed as being powered by Power clip/Beltpack/Backpack.
3. Powerful Energy Weapons refers to those weapons listed as being powered by a Minifusion Cell.
4. Radiation Weapons refers to those weapons listed as being powered by a Plutonium Clip.
5. The low number of shots available to "powerful energy weapons" makes for an interesting use of low power treasures, in other words, giving the PCs a powerful weapon with only a few shots left, early on in the game.
6. With using Minifusion Cells and Plutonium Clips in standard energy weapons, I might include a chance of the weapon exploding when fired, probably something simple, like rolling a Natural 1 on an attack roll, or some other fumble type mechanism.
Non-Discharged Items
Before my thoughts on alternate power usage in energy weapons, I was actually looking at the power sources and how they'd work in powering robots. Let's face it, in the Post Apocalypse, there's still crazy tinkers, (mad) scientists, whack-jobs, (crazed) inventors and the like who think making robots would be useful, and not all of them are going to have access to a Radioactive Battery. Now sure, I could just say, each type of power source can be used to power a android/cyborg/robot for the listed amount of time, but is that really the case? Also, what happens if the robot maker decided to use several of the same power sources (like, say, five Minifusion Cells) to power the robot?
ADDENDUM
Note #5 inspires this quick table for how many shots are left in that Power Source (roll 1d6) [Of course, one could always roll 1d10 for most power sources.]:
Roll Shots Remaining (based on base capacity of Power clip/Beltpack/Backpack, Minifusion Cells and Plutonium Clips use the first number)
1 1/2/5
2 2/5/10
3 4/10/20
4 5/12/25
5 9/20/40
6 10/25/50