While it's true that weapons don't generally come with ammo, they do generally come with a single magazine/etc. to hold the ammo you get later.
While our group decided that yes, you had to get the restricted gear quality a second time to pick up power packs for an energy weapon (as a way to keep it from becoming the default gun of the team), the argument could be made for a power clip to be included.
Now, if you are either required to (or choose to) take restricted gear again to get a good power supply, I'd go ahead and get the backpack unit. Only costs 2,200 and holds 80 power points (Ares Redline only spends 1 per shot). And with an availability of 20F, it falls within the limits of the quality. Now, because of the 'F' part you might want to consider dressing it up a bit to look more like a more normal backpack since it's not easily concealed like the clip or satchel pack are.