I stole
this excellent low-profile DIY solution for my 170ext, but should also work for a 144 if you have room.
Materials ordered from onlinemetals.com:
6061 Aluminum Angle (2" x 3" x 0.25")
2 pcs 84" long
http://www.onlinemetals.com/merchant.cfm?pid=19688&step=4&showunits=inches&id=62&top_cat=60
6061-T6511 Aluminum Rectangle Bar (1.5" x 0.25")
1 pcs 36" long
https://www.onlinemetals.com/merchant.cfm?id=997&step=2&top_cat=60
Cost was around $80 plus $25 for shipping.
I used the same panels (qty 4 of Renogy RNG-100D) and they are a perfect fit. Because I wasn't hiding the panels between two MaxxFans, I had to experiment with front-back placement because the array can be seen more easily from behind, due to the subtle curvature of the Sprinter roof near the 3rd brake light. I ended up with the rear edge of the panel frame just slightly overhanging the black plastic end of the OEM roof rail.
Didn't need to cut the 7ft aluminum angle at all. Used a jigsaw to cut down the 1.5" bar to make eight square spacers. Each panel is attached to the angle with 2 bolts per short edge (I drilled into the side of the panel frames), and also to neighboring panels with 2 bolts on each long edge. I used 1/4-20 stainless bolts, washers, and nylock nuts.
I placed both aluminum angles on the roof along with one panel and carefully marked hole locations for drilling. Spent the rest of the day indoors doing "mark, measure, drill, repeat". Had everything bolted to the roof a day later.
I overpaid for eight
roof sliders from Sprinter Store but could have made my own easily (and have since made extras). IIRC they were just 2" long sections of 1"x1/8" aluminum bar (available at Lowes/Home Depot), with a square hole in the middle, and a
1/4"-20x1-1/4" stainless carriage bolt that drops into the square hole. Don't forget SS washers and nylock nuts as well. If you start by drilling a round hole, you can then use needle files to make it square. A little tedious but doable especially if you plan ahead enough to spread the work over several days, making one or two at a time.
The array shades the roof nicely with around 1-2" of airspace from the roof to the underside of the panels. Very noticable in the summertime with no insulation. The roof was too hot to touch from inside, except for the area beneath the array.
The panels weigh about 66 lbs and the aluminum adds around 22 lbs to that. To bolt it all together I lifted up one side of the array at a time, propping it up with yoga blocks to get my hands underneath.
For a cable entry I used the
Linksolar part, mounted underneath the array to keep it out of sight and protect it from dirt, debris and UV.