So I let both my packs charge, my 3k and 5k 7.2v. I let them cool down like I always do and get ready to go outside. Turn the truck on and I hear a very half effort beep and then I smell burnt electronics. freak out and turn it off, little bit of smoke. The battery wire is now off and smoked a bit. Both the battery and the ESC smoked up. This happened to both my batteries. What the heck did I just experience.