Hi,
Well I have the laptop and it's running at well under 30W (from mains).
I have the remaining hardware to make up this switchover unit on order and should be delivered tomorrow, including the DC/DC converter.
And I got a new solar panel (62W) powerful enough to power the laptop at least while the sun is out for experimental purposes: I'll need a bigger battery and some more power (solar or wind) to be able to run it full-time even at this time of the year.
Rgds
Damon