Thinking of making a "aluminium tray " for underneath of roof rack mounted solar panel to cut down on wind noise,maybe?, The bottom of tray will still be 50mm above Landcruiser roof to give some heat relief and leading edge will be shaped a bit to blend into cross bar as well as hold it there. A bit like sitting panel in a baking dish. Any thought please appreciated. cheers Craig
PeterD said
07:54 AM May 30, 2017
Is this for storing your portable panel whilst travelling or are you mounting the panel there as a permanent spot for use? If it is for use in that location what obstructions will be across the top? Anything under the panel will impede the airflow to the bottom of the panel and thus raise its operating temperature. A diagram would be handy, draw it on a piece of paper, scan it as a JPG file and attach that file to the thread.
Bagmaker said
09:42 AM May 30, 2017
Apart from increasing the heat -as Peter mentioned - do you have any water drainage happening?
Aus-Kiwi said
12:47 PM May 30, 2017
If under rack it should be fine . With atleast 50mm gap between roof and planel . It obviously won't work with things stored on rack . I guess the support to hold panel can be off rack ? Which MAY require some strengthening..
Craig1 said
01:19 PM May 30, 2017
Shocking sketcher Pete, I want to keep the panel permanently mounted to maintain 2nd battery when not doing enough km's. The tray will need drain holes and each end will go up over the two rack bars. I would only ever have something light wight or small on other side of panel, not carrying a tinny. Panel is 1200 x 600. Thanks again
The aluminium tray will act as a heatsink transferring the heat from under the panel to a flat surface where the air can actually move across the surface. Keep the aluminium clean without painting either surface and it will be fine, the heat will transfer through the aluminium and the air between the dish and the roof will carry the heat away.
Aluminium makes a great heat transfer medium, that is why modern engine radiators are now aluminium rather than copper, copper absorbs a lot of heat energy but not very good at releasing it where aluminium doesn't store heat very well.
T1 Terry
Jaahn said
06:21 PM May 31, 2017
Hi Craig
My 2 current panels on my minibus are mounted to two roof racks. I have a piece of aluminum angle 50x50 screwed to the ends on the panels then the angle sits on the roof rack with some screws too. Works OK and been there for some 10s of thousands of Ks now. Was a fast easy way when they were put there for the first trip.
Jaahn
macka17 said
06:44 PM May 31, 2017
Angle Ally is better way.
I have two surf bars with Roll out hanging off nearside.
2 x ally angles fr to back. with panel sitting in them. Good airflow.
Mounted on 4 x Z brackets with lock nuts.
And swivel legs at front. that sit up alongside panel.
Remove Lock bolts. Slide panel forward so rear mount holes in front mount holes.
replace one set of bolts.
Front swivel legs do so. Down to top of Nudge bar and bolt on there.
For when gear on roof and still wanting to use panels.
either driving, or parked.
Also made a set up for mate coming out the side of racks.
Angle sliding in angle. and props drop to door sill.
There's lots of ways with a leetle thort.
If you want to HAVE a tray.
Thik about some ally angle and slide panel in out UNDER tray. so Tray still usable
And if you want panel usable while travelling. Slides Forward to bull bar
with short risers.
Nice visor for screen too. If you mount across car. (shrug)
Warren-Pat_01 said
09:56 PM Jun 4, 2017
Hi Craig,
A while ago one of the members was selling his solar panels & at the time I thought the setup on his roof rack was great. Have a look at the post (thegreynomads.activeboard.com/t62526617/solar-panels/).
Warren
---------------------------
Craig1 said
08:40 PM Jun 5, 2017
Thanks again all, still getting mucked around by supplier for roof racks,bullbar stuff. The main theory was to try to minimize wind noise for SWAMBO,cheeze & kisses, 46 year partner etc. Previous hd square racks on bt50 were quite noisy, so I figure with wind whistling up under solar panel frame I may not be too popular. (Extra cold riccadona may help , can only hope).
Will report in once fitted. cheers Craig
Reed said
05:55 AM Jun 26, 2017
We had 315 W panel ripped off in 60 to 70 mph winds (90 to 110 kmh) in Isthmus of Tehuantapec which is world famous for winds (3 km high mountains on either side of Isthmus where it is a maximum of 200 m so that high pressure on one side and low pressure on the other (Gulf of Mexico and Pacific) creates these winds. This occurred near the town of Los Ventos "The Winds" where seven 18 wheelers were rolled by hee winds in one day and where there are many km of wind farms. Had to use tie-down straps and Gorilla Tape to hold onto the back of the Roadtrek. We were asked how well this setup worked and had to admit it might work going north but we were headed south to Yucatan.
Younger son and family flew down to spend a week on the beach near Tulum and I got some 1.5" extruded aluminum channel. Bolted one section of channel to the frame of the panel after placing 5' x 1" x 1/8" alumiinum stripping inside the channel of the panel to prevent bolts pulling loose. It went a lot easier with a 36 year old son who completes in Brazilian Jiu Jitsu and teaches skiing. Screwed and silicone glued another 1.5" aluminum channel to the fibreglass roof of roadtrek and then bolted the channels together. Called older son in New Mexico about this concept (he has been in solar engineering since 1991) and he thought it a good idea. He examined it when we returned (we are at his place at 7800'/2300 metres in mountains of northern New Mexico) and said that this is how he would do if he ever does another RV installation (our rigs are the only ones he has done). Have examined mounts on our 34' (10.3 m) and looks as if we need to replace several of the 235 W panel mountains this fall.
Waste water system got knocked off soon after this and son and I repaired this on the beach (OK, Charlie did most of the work). Had to dig a ditch under the Roadtrek to get under. He brought down a section of sewer hose to do the repairs.
Reed and Elaine
um stripping so that bolts would not pull out. Bolted and silicone glued another
Why do you want to put anything under it / them at all ? Why not mount them on an right angle running longitudinaly , a channel in the middle between the roof bars slung such that you have the level of the panels below the level of the top of the roof bars? In case you want to put something ON the roof bars and want clearance for the panels ? All you really want is cooling under the panels and a bit of an air gap to keep the roof cool. Just make sure there is a bit of "give" in the mounts so they dont couple too much vibration and crack the panel to edge mount bondings and crack the panels ( unlikely but worth considering) .
Thinking of making a "aluminium tray " for underneath of roof rack mounted solar panel to cut down on wind noise,maybe?, The bottom of tray will still be 50mm above Landcruiser roof to give some heat relief and leading edge will be shaped a bit to blend into cross bar as well as hold it there. A bit like sitting panel in a baking dish. Any thought please appreciated. cheers Craig
Aluminium makes a great heat transfer medium, that is why modern engine radiators are now aluminium rather than copper, copper absorbs a lot of heat energy but not very good at releasing it where aluminium doesn't store heat very well.
T1 Terry
Hi Craig
My 2 current panels on my minibus are mounted to two roof racks. I have a piece of aluminum angle 50x50 screwed to the ends on the panels then the angle sits on the roof rack with some screws too. Works OK and been there for some 10s of thousands of Ks now. Was a fast easy way when they were put there for the first trip.
Jaahn
I have two surf bars with Roll out hanging off nearside.
2 x ally angles fr to back. with panel sitting in them. Good airflow.
Mounted on 4 x Z brackets with lock nuts.
And swivel legs at front. that sit up alongside panel.
Remove Lock bolts. Slide panel forward so rear mount holes in front mount holes.
replace one set of bolts.
Front swivel legs do so. Down to top of Nudge bar and bolt on there.
For when gear on roof and still wanting to use panels.
either driving, or parked.
Also made a set up for mate coming out the side of racks.
Angle sliding in angle. and props drop to door sill.
There's lots of ways with a leetle thort.
If you want to HAVE a tray.
Thik about some ally angle and slide panel in out UNDER tray. so Tray still usable
And if you want panel usable while travelling. Slides Forward to bull bar
with short risers.
Nice visor for screen too. If you mount across car. (shrug)
A while ago one of the members was selling his solar panels & at the time I thought the setup on his roof rack was great. Have a look at the post (thegreynomads.activeboard.com/t62526617/solar-panels/).
Warren
---------------------------
Will report in once fitted. cheers Craig
We had 315 W panel ripped off in 60 to 70 mph winds (90 to 110 kmh) in Isthmus of Tehuantapec which is world famous for winds (3 km high mountains on either side of Isthmus where it is a maximum of 200 m so that high pressure on one side and low pressure on the other (Gulf of Mexico and Pacific) creates these winds. This occurred near the town of Los Ventos "The Winds" where seven 18 wheelers were rolled by hee winds in one day and where there are many km of wind farms. Had to use tie-down straps and Gorilla Tape to hold onto the back of the Roadtrek. We were asked how well this setup worked and had to admit it might work going north but we were headed south to Yucatan.
Younger son and family flew down to spend a week on the beach near Tulum and I got some 1.5" extruded aluminum channel. Bolted one section of channel to the frame of the panel after placing 5' x 1" x 1/8" alumiinum stripping inside the channel of the panel to prevent bolts pulling loose. It went a lot easier with a 36 year old son who completes in Brazilian Jiu Jitsu and teaches skiing. Screwed and silicone glued another 1.5" aluminum channel to the fibreglass roof of roadtrek and then bolted the channels together. Called older son in New Mexico about this concept (he has been in solar engineering since 1991) and he thought it a good idea. He examined it when we returned (we are at his place at 7800'/2300 metres in mountains of northern New Mexico) and said that this is how he would do if he ever does another RV installation (our rigs are the only ones he has done). Have examined mounts on our 34' (10.3 m) and looks as if we need to replace several of the 235 W panel mountains this fall.
Waste water system got knocked off soon after this and son and I repaired this on the beach (OK, Charlie did most of the work). Had to dig a ditch under the Roadtrek to get under. He brought down a section of sewer hose to do the repairs.
Reed and Elaine
um stripping so that bolts would not pull out. Bolted and silicone glued another
Why do you want to put anything under it / them at all ? Why not mount them on an right angle running longitudinaly , a channel in the middle between the roof bars slung such that you have the level of the panels below the level of the top of the roof bars? In case you want to put something ON the roof bars and want clearance for the panels ? All you really want is cooling under the panels and a bit of an air gap to keep the roof cool. Just make sure there is a bit of "give" in the mounts so they dont couple too much vibration and crack the panel to edge mount bondings and crack the panels ( unlikely but worth considering) .