GravelRider wrote:
How many mounts should I use on a panel this big (80" x 40")?
4 mounts for the panels themselves. You need to determine what is adequate for your roof.
I used 4 for my 60 cell panels (slightly smaller) which should have been adequate and in fact drove many miles with the 4. However as a result of the install I had a way to pull up on the roof and discovered that in the center it was not attached to anything. Later I installed 4' al angle and long screws to reach the flat ceiling cross beams and added 2 more panel mounts.