Here are some links & notes I pulled together during my last research dive into solar e-bikes. Between the youtube channel, the presentation from the GRIN / ebikes.ca folks, and the info on the GRIN & Sol Mobil websites you should be able to get a pretty good notion of how the Sun Trip bikes are wired up. GRIN sells a
solar conversion kit, and Sol Mobil sells some of the parts, and from looking at their websites I bet both would be willing to answer questions.
Ok, links & notes:
how to charge your ebike with solar panels - https://www.youtube.com/watch?v=X78VCsYJjbA&feature=youtu.be
genasun chargers are expensive - there are cheaper ($50) alternatives, but not as good
use SunPower cells - there are varying degrees of efficiency
he used SunBeam Systems, but any brand with sunpower cells is good
at least 80W panels, ideally around 160W (maybe 200)
lots more videos from this user w/ details about building and testing a solar trike
sun trip presentation from GRIN / ebikes.ca folks - https://www.youtube.com/watch?v=15HHLY4BfA4
1kwh battery max allowed for the trip (about double standard ebike battery?)
400W solar panel max allowed for the trip (550 tandem)
tilting panels didn't make much difference when riding since it's mostly an east-west trip
even on sunny day, never hit more than 80% of panel's power rating
over the course of a sunny day, they could get 3000wh from their 550w panels (=six standard 500wh batteries)
even on the worst, rainiest day, they got 1000wh from the panels
most riders on the trip averaged 4wh/watt (e.g. if you need 1000wh over the course of the day, use a 250w panel)
solo riders get about 1km/8wh (GRIN normally quotes 1km/10wh for average riders - sun trippers were pedaling harder)
tandems get about 1km/14wh
don't expect dramatic improvements in battery tech
do expect significant improvements in photovoltaic tech (currently 25% is really good, but cutting edge is 40% efficient)
the difference between a 22% efficient panel and a 27% efficient panel is doubling or tripling the cost
sol mobil - shop in appalachia owned by Sun Tripper, sells the good charge controller - https://www.sol-mobil.com/
solar bicycle camper / pedal powered mobile home - a little silly, but fun - https://www.youtube.com/watch?v=hR-E55RZqQs
czech solar team - http://czech-solar-team.com/
solar trike conversion in comments - https://www.instructables.com/id/Sun-Basket-Univeral-Solar-Bike-Upgrade/
one sun trip winner - https://www.vanhulleraf.be/cycle
Sorry that's not more organized; I hope some of it is helpful!
-Darin