Solar Panels in windshield power loss

BurntTech Registered Users Posts: 8 ✭✭
I'm curious if anyone has or still puts solar panels in their windshield. The main reason for looking for putting them in the windshield is for them not to get stolen. I'm currently looking at flexible 100 watt panels(no glass). My thoughts are if you leave out at campsite some would take a panel or two at that size without thinking(minus people with morals). If we left for hiking or what not for the afternoon to throw 2 of the flexible solar panels in the Winnebago Paseo 48p windshield. Its based on the Ford Transit 350 HD Chassis and the windshield doesn't "look" tinted. From my research I've heard 10-40% loss but no real tests from what I could tell. If anyone has tried this I would be curious on the amp loss?


  • BB.
    BB. Super Moderators, Administrators Posts: 33,409 admin
    A simple test. Get any solar cell and connect it to an DC amp meter. Measure the current in full sun, and behind the windshield glass.

    Plain window glass (not tinted/UV limiting) will probably cut the solar panel output by 40%. Add tinting/UV/IR reduction, probably even quite a bit more.

    For larger panels, I would suggest permanently mounting to the roof (possibly with the ability to angle, depending where you camp and how far north you go, winter/summer), is a better solution.

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BurntTech
    BurntTech Registered Users Posts: 8 ✭✭
    I'll try it with my rigid 100 watt and see what I get. The roof already has one 100 watt rigid panel on the roof, i'm also in addition looking at what panels would fit on the roof. Its not looking with most areas with free space is 14 by 30 inches or get taller mounting brackets to go over the water vents and such. It uses zamp 500 watt controller and hub (3 plugs on the roof) and one portable on the side. I figured the rigid panel would end up farther away from the glass then the flexible ones. Not sure if that adds to the loss with having space between them.
  • Solray
    Solray Registered Users Posts: 246 ✭✭✭
    I'd just put them on the roof. No one is going to climb up on a roof to get something that cannot be seen.
  • BurntTech
    BurntTech Registered Users Posts: 8 ✭✭
    Just a quick update for those interested in trying this. I'm using two light weight folding 100 watt panels(4lbs a piece) in the front windshield of the RV and appears to maybe a 10% or less loss. The biggest problem is the panels aren't at the best angle for the sun. Second problem is the sun moves and normally shades one or both panels at some point. Even at the wrong angle 200 watts worth of panels its producing 10-30 percent more then my permanent 100 watt panel on the roof of the RV. If I can't park the front of the rv horizontal to the sun it makes for a rough solar day. Project is to get 2 more 100 watt rigid panels on the roof and keep using folding 100 watts for total of 500 watts. Having the portable ones does make a difference in our tests for supplying power for the fridge as the more sun out the more the compressor kicks on. So I would recommend looking into these lightweight (don't think they are totally weather proof) if you need little extra power. Takes only 1-2 mins to throw them up front when we go hiking or if we hanging around the site just throw them in the grass. Also for reference my windshield really does look like it doesn't have any tint even compared to cars.

    100 Watt rigid mounted flat = Avg 3-4 amps
    100 watt folding panels = Avg 2.5 (while sun fully hitting windshield)
    so a average day is 2.5 x 2 + 4 = 9 amps, low end about 7amps, high end so far 10amps

    If I could get the angles setup I could get closer to their 5.5amp rating but that is a different possible project
  • oil pan 4
    oil pan 4 Solar Expert Posts: 767 ✭✭✭✭
    Yes I have also found athat least 40% to 50% reduction in power also when placing solar panels inside vehicle glass.
    That's why mine are on top of the vehicle.

    Solar hybrid gasoline generator, 7kw gas, 180 watts of solar, Morningstar 15 amp MPPT, group 31 AGM, 900 watt kisae inverter.

    Solar roof top GMC suburban, a normal 3/4 ton suburban with 180 watts of panels on the roof and 10 amp genasun MPPT, 2000w samlex pure sine wave inverter, 12v gast and ARB air compressors.