Light Transport pilot reported a complete loss of avionic systems resulted in a return to the departure airport.

Narrative

On the evening of Date; I was on an IFR flight from ZZZ to ZZZ1. On departure I was leveling off at 6;000 feet and had a complete avionics shut down. I had a dark cockpit and back up Attitude indicator with no heading reference. I was in moderate turbulence and full IFR conditions. I turned on my Flashlight and ran through quick check and reset procedures. I was hand flying and getting bounced around pretty good. The one passenger sitting behind the co-pilot seat asked if she could help in anyway. I asked her to open up Google earth and pass me her phone. She did so and I was able to make turns away from terrain and back towards ZZZ. I had no radios and stayed along the south side of the inlet and made my way for a downwind outside of ZZZ to set up for an approach. Around [then]; my avionics began to come back alive and approach control called me immediately. I informed them of my situation and they set up a plan for a PAR into ZZZ. After several minutes my equip continued to reboot during the turns for ZZZ. I informed them of the changes and requested to continue with the PAR. Once on final Approach to Runway X Right my localizer needle centered and my flight director appeared to be giving me normal indications. At the final approach fix the glide slope came into position and I requested the ILS to get lower. I broke out and had the runway at 1;400 ft. and was transferred to Tower. I continued and made a normal landing and was instructed to taxi to parking and have a goodnight. Talking with aircraft manufacturer and Maintenance we have not settled on what happened to the panel. Manufacturer suggested possible static discharge which kicked system offline. It was a taxing ten minutes while I was on standby systems with no radios. I was happy for Google earth. The take away from this is training; training; training. I reverted back to basic IFR mode straight and level and situational awareness. Google earth allowed me to bake safe directional changes. As the Chief Pilot I will share this experience with my pilots and work it into training and run refreshers procedures.