Solar Blvd puts a flexible 120 W solar panel
on sale frequently as low as
about $120.  Right now it is $139, regular $179.
https://www.solarblvd.com/products/solar-cynergy-flexible-bendable-120-watt-12-volt-solar-panel-3/

Two things make it perfect for a Westy.  1) It
fits on the roof between two raised sections:
http://jones.colorado.edu/VW/VWsolar/roofpanel.jpg

and 2) it stores very nicely on top of the folded top
bed when you drop the top.

It puts out ~6 A
http://jones.colorado.edu/VW/VWsolar/label.jpg

If you park so that the pop top isn't getting much
sun, it works fine on the ground with a longer cable.

Richard
'87 Westy Syncro