I like this idea a lot. How many spare batteries do you think a laser or scrambler should carry? I'm thinking 7 for laser rifles, and 10 for scrambler rifles.
An assault scrambler rifle should overheat when about 70-80 automatic shots have been fired to keep it consistent with the current magazine size.

By the title, I mean that all Amarr weapons use batteries instead of magazines/clips/whatever, which are destroyed when you overheat your weapon. So, if you carry Amarr weapons, you will also have a few spare cells

So if you are smart enough to not let your weapon overheat, it would literally have infinite ammo? Idk if you have used the AScR before, but I have literally never overheated it, unless they bump up overheat rate on all weapons it might get out of hand.

By the title, I mean that all Amarr weapons use batteries instead of magazines/clips/whatever, which are destroyed when you overheat your weapon. So, if you carry Amarr weapons, you will also have a few spare cells

Chances are in the future super compact nuclear cells, or very efficient hydrogen fuel cells, will lead to these types of weapons having an infinite set of ammunition.

So if you are smart enough to not let your weapon overheat, it would literally have infinite ammo? Idk if you have used the AScR before, but I have literally never overheated it, unless they bump up overheat rate on all weapons it might get out of hand.

I suggested in an earlier comment that the ASCR should overheat after firing 70-80 automatic shots to be more consistent with its current magazine size.
Also the amount of spare batteries could be much lower than the spare magazines of regular weapons as a tradeoff for the potential infinite ammo.

Would also like to add that overheat is much less penalizing than simply reloading, so that's also a balancing feature.

By the title, I mean that all Amarr weapons use batteries instead of magazines/clips/whatever, which are destroyed when you overheat your weapon. So, if you carry Amarr weapons, you will also have a few spare cells

I think Amarr weaponry should work similar to EVE Amarr weaponry; Frequency Crystals.

So instead of this battery you talk about maybe the battery could be a crystal pack instead. Depending on the crystal type you use, would change its effective ranges and the way to know if someone is using close quarter or a long range crystals would be the colour of the beams. This could also add a new skill subcategory under weaponry = Ammunition; including the different racial ammunition types; Laser, Projectile, Explosive, Plasma and Magnetic (Rail Gun Weaponry)

Frequency Crystals.
Basic
Yellow = Average RoF & average damage.

Advanced
Not too sure if Advanced ammunition type would be needed. Instead the ammunition skill would increase the longevity of the crystals. (Larger clip size.)

Prototype
Red = Long Range - Low RoF but high damage.
Green = Medium Ranged - Balanced between the two.
Purple = Close Quarters - High Rof but low damage.

Also scrambler pistol should get overheat as well