I did not make the art. I'm using pre-made assets I got for free from the unity asset store. I was in a rush just to publish what I had so I didn't get a chance to credit the people of who's assets I'm using. I'll be sure to do so on the playable version.
The batteries will blink when charging. Right now I have them blinking one at a time but it's not as obvious as it needs to be. I'll have them turn on in a sequence which should help convey the message of "charging".
Thanks for the feedback! I'll be sure to let you know when I have a playable version available!