Not sure how or why – but I wonder if charging through solar panels somehow conditions the battery more effectively – Ian has always had good range and the only one that I am aware of who has solar panels that can be directed to charge car !!??!
If @Ian Websell as you say is connecting his solar panels to charge the car and say he only has a 4/5kw system it will condition the battery better. Even on a 8kw will also likely condition the car better by design of the system
A little experiment mate. When your battery levevel is low and your not going anywhere that day, use the granny charger to fully charge the battery 🙂