Been away from my Niro PHEV for several months. Dealer and factory had no idea what to do, but it was simple. First, I ran the traction battery down to about 50%, or 13 miles of range. Then, there is an on-off switch in the fuse panel which disconnects the traction battery. Last, the 12 volt battery in the passenger side rear was disconnected. When I got back, I just reversed the procedure and the Niro came back to life with battery SOC exactly like I left it. However, I did forget how everything worked!