Have not used the MC3 for several months. Just lug it around in the flight bag. Pulled it out with one battery left to use. I'm bad when it comes to "maintenance " of it. All other hardware I check monthly regarding charge level. After all these months it still had 4 LEDs light up. Cool. Powered up the quad. No MC3 connection. Powered it off and back on. Still no go. Powered off and on the MC3. Still nothing, but I had a connection in the goggles. Oh well. No big deal. It's just a back up to the FPV RC3 and I'm not fond of it. Slipped the goggle off and there sitting on the bag was my RC3 still powered on. Switched it off. Powered on the MC3. All was good.