Need a robot-loader. Upgrade to the vehicle recharging device. Installs in the same place; over stuff with storage.
When it’s on, it acts like a vehicle re-charger, but it also detects if any adjacent connected frames have turrets or mountable guns that use non-battery ammo. If they do, and there’s a relevant ammo in the storage space underneath, the robot will use battery to load the turret until full. Would be incredibly handy for something like a slingshot turret, where you can only load 1 lead ball at once.