Mileage effect solar panel minivan roof?

[WalkaboutTed]

Hokey squares, folks,
The question of the hour, for a friend. Roughly, how much will a solar panel, mounted with the Renogy type z brackets, cut into  the mpg of a minivan? 

I couldn't find anything in a quick search.
Thanks,
Ted

 

[Spaceman Spiff]

There are a few dependancies based on how the windshield pushes air over the roof but the general answer is that if the panel is mounted back away from the leading edge of the roof there should be no easily measurable milage effect.

 -- Spiff

 

[minimotos95]

More so with Z brackets it will be close to the roof, I wouldn't even expect to see a loss of 1mpg(5% of what I would call average minivan MPG). It's the tall, Yakima, Thule, or ladder rack style racks and accessories pit om those that really drop your economy by 5-30+%

Of course it also depends on other factors like speed, at 55mph it may not be measurable while at 75 it devastates the fuel economy.

 

[Vanholio]

More so with Z brackets it will be close to the roof,  I wouldn't even expect to see a loss of 1mpg(5% of what I would call average minivan MPG). It's the tall, Yakima, Thule, or ladder rack style racks and accessories pit om those that really drop your economy by 5-30+%

Of course it also depends on other factors like speed, at 55mph it may not be measurable while at 75 it devastates the fuel economy.

I've got panels mounted on the Z brackets atop a rack on my minivan. I also have a wind faring. At 55mph, I do close to the van's spec mileage. At 75, I lose 30% efficiency. But then, I'm not sure how I'd do at 75 without anything on top.

 

[Trebor English]

My 100W panel is bolted to the original Ford suppled luggage rack. The rack is all the way forward due to the Maxx fan. No difference in mpg. All the back seats are out saving 200 lbs causing rear to be a bit higher than original.

 

[SternWake]

My full size van with TV top roof, seemed to take a slight highway MPG hit with a panel near the back of the roof, but there could have been other contributing factors to that 10 year old observation.

I try to look at it as this

Each 25 amps the alternator has to make requires 1 HP from the engine.

My 198 watts solar can make 13 amps in summertime at noon, thus reducing the work load on the alternator and thus engine, when batteries are depleted.

 

[makenmend]

Just before leaving E Texas for the RTR I installed solar using Ford factory bars and 'L' brackets. I have not noticed any significant change in fuel consumption.
Now wind noise ( at freeway speeds ) is another issue altogether, but have a wind shield/fairing on the way.

MM

 

[akrvbob]

Just before leaving E Texas for the RTR I installed solar using Ford factory bars and 'L' brackets. I have not noticed any significant change in fuel consumption.
Now wind noise ( at freeway speeds ) is another issue altogether, but have a wind shield/fairing on the way.

I'd be very curious to know about your windshield/fairing for your panels when you get them!