Posts: 113
Joined: Sat May 31, 2014 1:59 am
Delivery Date: 24 May 2014
Leaf Number: 339296

Re: Idea for Nissan

Sat Aug 02, 2014 10:47 pm

Zurc wrote:There is about 3000 Watts in a square meter of Sunlight to be had.
Not quite. The actual figure at the surface of the earth is about 1000 watts per square meter. If you go above the atmosphere, it is closer to 1366 watts per square meter. Neither comes close to 3000 watts.
so assuming 44% efficiency, that's about 1320Watts which at 12V would be around 110 amps.
So if the entire leaf roof was used, it could probably do some serious charging of that 12V battery.
It would be nice to know what that panel on the Leaf is capable of.
The roof is not normally aimed direcly at the sun. (The sun is not directly overhead. If the sun is 30 degrees above the horizon, you would only get half as much energy. Actually less, as it goes through more atmosphere.)

The maximum efficiency of a single junction solar cell is only about 37 percent as I recall, and the real panels are lower, around 18 - 20 percent, even less in implementation due to gaps between the cells, etc..

If you get 150 watts from the top of a leaf, you would be doing pretty good.
Normally there's about 2A on a trickle charge so unless there's a really efficient panel there, I seriously doubt it can do much.
More realistically, the trickle charge panel likely produces about 0.04 amps.

Posts: 89
Joined: Sun Sep 11, 2011 8:19 pm
Delivery Date: 06 Aug 2011
Location: SJ, CA
Contact: Website

Re: Idea for Nissan

Sun Aug 03, 2014 12:08 am

You can get the same trickle charge by keeping a small panel on your dash. I got a couple of them from Harbor Freight, just to keep my pickup ready for use. Cost around $15. Truck sits for months and the parasitic draw from it's alarm system eventually drains the Optima battery. One panel is enough, but once I left the dome light on after a trip and needed to actually put it on a charger to use it a few weeks later, so now it has 2 hooked up directly to the battery. They are about 6" X 12" or so and come with suction feet and some different connectors, including the lighter size and a pair of clamps.

Maybe I should replace the dome light with an LED...
'11 Volt and '14 Spark (with QC) in SJ, CA

Posts: 1219
Joined: Thu Mar 08, 2012 9:13 am
Delivery Date: 08 Mar 2012
Location: Plano, TX

Re: Idea for Nissan

Sun Aug 03, 2014 7:34 am

and don't forget the extra weight you add due to the generally much heavier solar panels compared to the material the body is generally made of.

In the end you will end up getting less range due to lugging all the extra weight. Solar panels are good for stationery use, except only in space in satellites where the surface area is so large the weight really doesn't matter what with zero gravity.
2011 Leaf, 30K miles, returned after 24 month lease.
Currently leasing 2014 Leaf SV.

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