The rechargeable batterys exist. And proof that they can EASILY be made to be tradable and such.
So what I am thinking is, selling Bound on Equipt verisons of EVERY Rechargable battery.
Say 500 Per battery, with a 1250 Zen combo that comes with all 4. And as a fix, make the batterys slightly weaker then normal batteries to balance it. And make it so you can Stack them up to 5. If you have a stack of 2, the skill becomes, Dual Charge, and it will have +70 Power, (opposed to 65, 75 is normal bat)
Stack 3, get Speed Charge, +70 power, and -20% Cooldown. Stack 4 get a Hypercharge, +75 power -30% Cooldown, Stack 5 get Power Overload, Which is +100 power for Double the normal battey duration, but with +50% Cooldown, AND after the battery is done, for 10 seconds u get -20 (nonresistable) drain to that subsystem.
This idea would be great, the battery stacking would make it more desirable to have many on 1 character.