From Geelong, Victoria, Australia.
I went away for 4 months and left my 2016 Outlander PHEV outside. It does not have wifi as it is the base model. The main drive battery was fully charged up before I went away (but not connected), which I thought would be fine.
Upon my return and power up (4 months later), I was getting several error messages on the dash, esp the Parking Brake malfunction or stuck, or something like that. Funny things going on with wipers etc. The main drive battery appeared to be fully charged, which I did try to charge again from the mains, but the charger cable was also showing it was full. It would not take any electrons.
Error messages on the dash went on for about 10mins and then nothing, no lights at all, the doors would not even lock. Not a LED light to be seen anywhere.
I rang Mitsubishi service who suggested I get a tow truck and "deliver it to use and leave it with us for a month... we are super busy, but we will get to it as soon possible" ... I consulted google.
I purchased a trickle charger and attached it to the terminal/earth under the front bonnet for about 6 hours. Still nothing. There was perhaps something happening inside somewhere as a faint rhythmic beating could be heard within the inner workings of the PHEV. Still no lights anywhere...
I purchased a jumper cable and pulled up another small diesel-powered SUV next to it, leaving the SUV engine on. Upon careful connection of the jumpers, the Outlander sprang to life and the "don't run me over pedestrian shizzer" started going again along with all the dash lights as per a normal start-up. I left the jumper cables attached for only about 2 mins and disconnected them. The main drive battery was still showing full. I drove to a service station to put some air in the tires which had gone down a little.
So far so good. Everything seems to work fine, although the trip computer and I presume the service computer seem to be reset as the very annoying spanner icon and "service me now" thing is gone, and there is no economy long-term history.
Happy days so far. I will update this post if there are any problems such as the 12v Aux playing up again and needing to be replaced.