You can blame me for the the solar panel
More on that later.
If you watch the CAN bus while driving, you can see occasionally see the DC-to-DC converter running to charge the 12V system. This pulls a bit of energy out of the traction pack and charges the AUX battery. If you have the solar panel, this would happen less often, so you could get an extra bit of range. How far? Here is a quick napkin sketch:
Assuming the panel makes 100Wh on a given day (this is optimistic) and that completely offsets 100Wh from the traction pack, you'd have that much more for driving. Assuming 250Wh per mile, that will get you 0.4 miles.
If your car is kept under covered parking during the day, it would be even less. So the solar panel is a token, albeit an important one I would argue.
I got to meet with Mark Perry and Nissan execs from Japan in 2008 and I told them the story about whenever I had my electric truck at an EV event someone would suggest putting a solar panel on there with a statement like "This runs on electricity, solar panels make electricity. You should put one on there and just drive all day long." I would explain solar related things like available surface area, angle, and efficiency details. Often during this explanation their eyes would glaze over. So eventually, I changed to just saying "Well, I have solar on my house. It works better there since I never park my house in the shade."
I told the Nissan folks that they could avoid a deluge of email in their inbox from well intentioned, uninformed people by adding a solar panel; even if it is just a single small panel that is only offered as an overpriced accessory. It does not need to add any range it just needs a token function such as running a cooling fan. This gesture would make some customers happy.
I also suggested the range rings on map and asked for 3G charging station location updates since the infrastructure would be growing quickly during this time and I would not want to schedule dealer appointments for map updates each month. I was happy to see that Nissan did all of these. I wrote about all the things I suggested here