Empty fuse slot on drivers side?

[The_Ghost]

I've been looking for an empty fuse slot that is powered by ignition on only. I have a twin camera system that runs off of a backup battery, but I only want it to charge the battery when the ignition is on. On the drivers side fuse panel, slot 25 is for a 10A USB, but the fuse slot is empty. Has anyone used this slot and is it powered on only with ignition?

 

[shbox]

I'd check it with a meter to see, regardless of feedback.