How much power is lost w/ folding solar panel placed INSIDE cars windshield?


Solar Enthusiast
Jun 28, 2021
I am charging my Ecoflow Delta 1300 “solar generator” with two 100 W panels mounted on the top of my Toyota Sienna minivan. I would like to add more solar so I was thinking about buying a 100 watt (or more) FOLDING solar panel.


1) How much power will I lose if I place the folding panel on my car‘s dashboard against the INSIDE of my windshield? Let’s say in ideal conditions I’m getting 65 watts from the 100 watt folding panel when it’s outside, then how many watts would the same panel produce on the same day placed at the same angle when it is INSIDE my front windsheild?

2) I would still have the two 100 watt panels charging the Ecoflow while using the folding panel. Ideally I would use a short MC4 “Y” adapter that is always plugged into the Ecoflow solar generator so the fixed panels on the roof are always connected and would enable me to quickly connect and disconnect the folding panels. Does that kind of MC4 connector exist? Is that how you would do this?



New Member
Sep 21, 2021

The answer to 1 is: it depends.
It depends on the type of glass your windscreen is, maybe it is covered with metal or has anti heat loss cover.
It is probably comparable to my 100W panel facing south with 2 half dirty glasses in front of it. However, I get maybe more than the normal radiation because of the sea reflecting a lot of light.
So on this setup, i get 35W out of a 100Wpanel in december at midday for about 1 hour.