Solar panel location

[Steve F]

So I got given a 167W 24V panel today and it's big. My question is how critical is the location, obviously there are some ideals but with the size of it and my requirements it may be a non issue.

Here's my setup, 100AH sealed battery, all LED lighting, car stereo and fold down DVD player (lucky to use 1hr a day) and the occasional charging of laptops and phones etc. The fridge stays in the Jeep most of the time hooked to it's second battery but may occasionally come out and hook up to the camper if I dont drive anywhere for a few days and the second battery starts to run down.

I was planning on mounting the 167W panel on the roof behind the RTT and pretty much have it setup there permanently. I also have a 30W panel that I place in the best spot as the sun moves around, so all up I'll have 200W on separate regulators, the one for the big panel takes a 24V input and gives an output suitable for 12V batteries its also a MPPT regulator. I have no provision for 240V (none of that 120V here)

Anyway, here's a pic of my free panel and the size. A quick test at 3:00pm on a winters afternoon with dappled sun and it was putting out just over 3A



Cheers
Steve

[Shadow Catcher]

From what I understand the only constraint is to eliminate shadowing on the panel as much as possible. Being able to tilt the panel toward the sun is a plus and I am trying to come up with a design that will allow me to do that in four directions with the panel mounted on the roof.
I need to be able to actually play with the panel on the trailer to be able to visualize a design with sufficient flexibility. Hopefully that will happen this week.

[dreadcptflint]

For me after last years test, panel location doesn't matter too much. I am running a 135 and usually under some pretty poor conditions. i.e. the panel was shaded, it was over cast etc. My battery was fully charged around 11 AM. This was after full use of my CPAP at night, water pump and lights (my wife needs the light on to cook). I have the tilt option on my panel however I don't think that I will ever use it.

You might want to just hook everything up in the driveway one weekend and test it with the panel flat on the roof. With a panel that big, you might be able to get away with running everything and not having to move the panel.

[bdosborn]

From what I understand the only constraint is to eliminate shadowing on the panel as much as possible. Being able to tilt the panel toward the sun is a plus and I am trying to come up with a design that will allow me to do that in four directions with the panel mounted on the roof.

Ditto on the shading, even a little bit (like from a single leaf) will cripple the panel's output. Your panel's big enough that you probably don't have to worry about tilting it. The 30% reduction in panel output from lying flat will still allow you to charge your batteries easily. I've only tilted mine once while camping, just to see if it worked right. Here's how I tilt mine, I use legs and a swivel:



The front panel doesn't tilt because it would shade the back panel. I have a jumper cord that runs from the trailer to the truck if I'm going to stay somewhere a few days. That way I don't have to take the fridge out of the truck but I can run it off the solar panels.

Bruce

[Yota Bill]

Shadowcatcher, here is one way you could make a mount that would tilt in 4 directions:
build 3 squares out of angle steel that match the outside dimensions of the panel. On the first one, weld a tab in the center of the N and S sides. On the 2nd square, weld a tab on the E and W sides. Each tab would have a single hole in it. Stack the squares on top of each other, and spaced apart to allow for them to tilt, then mark and drill a hole to align the hole in each tab with the corresponding angle above it. The panel would mount to the top square. The amount of tilt would depend on the separation of the squares, and the length of the tabs, in respect to the overall size of the square.
It would work, but would be limited on how much it tilts without getting extremely tall.

I would think a better option would be something similar to what bdosborn posted (pivot at one end, stiff arms to raise the other end) and then just make the whole thing spin (scavenge some pieces from an old office chair for that). Put some stops on it to keep it from continually spinning and wrapping up the wires, and maybe a "pigtail" coiled wire so that it stretches as needed. That would allow you to point it much more accurately, and would not be excessively tall.

[Shadow Catcher]

Based on Bruce's experience I will see if there is a need to tilt before doing anything. The mounts I have are ABS that will be attached using 3M VHB tape so no holes in the roof. I have a 25W separate panel that can be set up out in the sun when we are in shady areas with its own PWM controller.
At this point I do not know what our usage will be all of the lights are LED but there will be the water pump, Sirius/stereo radio and the TV and or Satellite receiver (not likely to get used much except for nasty weather or checking weather).

[Steve F]

I ended up using some H profile aluminium with angle bracket on top to make a raised platform that guides the panel off and on. I'll add some carpet on it so I can slide the panel on and bolt it down in each corner. Then when I reach my destination I'll either leave it on the roof or unbolt it and slide it off and put it in the optimum spot.

My regulator reports how many amps have gone into the battery so I'll see what I get in a day with it on the roof and if it isn't enough then I'll take it off and place in the better spot.



Cheers
Steve

[bdosborn]

Boy that's a big panel, I think I have panel envy.

Let us know how it works, I bet you'll be very happy it...

Bruce