Temporary pole mounting

[lkruper]

I have been considering setting up solar panel at my cabin on some sort of ground mount, getting it all working and then storing the panel for an emergency. The wiring will all be tested and ready to deploy in the event of a prolonged power outage. My reasons for doing it this way include:

1) I am not always there and how can one secure a panel that could be stolen?
2) There are restrictions for modern looking devices on Forest Service Land.
3) We get potential high winds in the location I think is best.
4) I would like the flexibility of taking this somewhere else, on a trip either camping or RV.
5) I am looking for something like a 300w panel to maximize amperage with MPPT.

Is it possible to set up a secure ground mount that is also convenient to deploy or store quickly? The ground is extremely rocky and digging a large hole would be very labor intensive, but I don't see a good alternative.

[SunEagle]

I have been considering setting up solar panel at my cabin on some sort of ground mount, getting it all working and then storing the panel for an emergency. The wiring will all be tested and ready to deploy in the event of a prolonged power outage. My reasons for doing it this way include:

1) I am not always there and how can one secure a panel that could be stolen?
2) There are restrictions for modern looking devices on Forest Service Land.
3) We get potential high winds in the location I think is best.
4) I would like the flexibility of taking this somewhere else, on a trip either camping or RV.
5) I am looking for something like a 300w panel to maximize amperage with MPPT.

Is it possible to set up a secure ground mount that is also convenient to deploy or store quickly? The ground is extremely rocky and digging a large hole would be very labor intensive, but I don't see a good alternative.

Having a ground mounted pv system does not mean needing a permanent structure.

I built one out of 80 and 90 watt panels that can be moved and tilted to multiple angles. They can be weight down with something like sand bags but will not stand up to high winds. I am sure you can build something similar with a 300 watt panel.

Attached is some pictures along with the combiner box which can accommodate up to 5 panels.

[lkruper]

Having a ground mounted pv system does not mean needing a permanent structure.

I built one out of 80 and 90 watt panels that can be moved and tilted to multiple angles. They can be weight down with something like sand bags but will not stand up to high winds. I am sure you can build something similar with a 300 watt panel.

Attached is some pictures along with the combiner box which can accommodate up to 5 panels.

Thanks, that looks nice. I have not researched combiner boxes.... something on my list of things to understand. If I had more than one panel and they were wired together would you need a combiner box? Also, while I would probably have just one big panel, my area is wooded but has a few spots that get exposure from a certain direction during parts of the day. I have one area with pretty good southern/western afternoon exposure and one with mid-morning eastern exposure. If power was out completely and I was trying to conserve generator gas, could I use a combiner for these two panels even though they would likely be 50 or more feet apart from each other?

[inetdog]

Thanks, that looks nice. I have not researched combiner boxes.... something on my list of things to understand. If I had more than one panel and they were wired together would you need a combiner box? Also, while I would probably have just one big panel, my area is wooded but has a few spots that get exposure from a certain direction during parts of the day. I have one area with pretty good southern/western afternoon exposure and one with mid-morning eastern exposure. If power was out completely and I was trying to conserve generator gas, could I use a combiner for these two panels even though they would likely be 50 or more feet apart from each other?

If you have only two panels in parallel you can just use a wye cable or splice in a junction box.
But for three or more parallel panels or strings you need to have an individual fuse or breaker for each string. The combiner box is the easiest way to provide for that overcurrent protection.

[SunEagle]

Thanks, that looks nice. I have not researched combiner boxes.... something on my list of things to understand. If I had more than one panel and they were wired together would you need a combiner box? Also, while I would probably have just one big panel, my area is wooded but has a few spots that get exposure from a certain direction during parts of the day. I have one area with pretty good southern/western afternoon exposure and one with mid-morning eastern exposure. If power was out completely and I was trying to conserve generator gas, could I use a combiner for these two panels even though they would likely be 50 or more feet apart from each other?

You only need a combiner box with over current devices (fuses) if you have more than 2 panels wired in parallel.

I have to wire mine in parallel because I am using a PWM CC which does not have the voltage range for me to wire my panels in series.

You are making the correct move to use a higher wattage grid tie panel then a number of smaller wattage ones I used. The $/watt is lower for those bigger panels.

If you have 2 of those 300 watt panels they could be apart from each other but I would make sure they are the same distance to the charge controller. Just be careful with low voltage DC wiring. It is easy to exceed a 2% voltage drop if your wiring distances are far and the wires are not big enough.

I hope you are looking at an MPPT charge controller. You will get more out of your panels going that way then with a PWM type like I did.

[SunEagle]

If you have only two panels in parallel you can just use a wye cable or splice in a junction box.
But for three or more parallel panels or strings you need to have an individual fuse or breaker for each string. The combiner box is the easiest way to provide for that overcurrent protection.

Do you have any idea why my attached pictures are much bigger then when I use to attach them to a post? Before they were no bigger that then small ones at the bottom of my post.

[inetdog]

Do you have any idea why my attached pictures are much bigger then when I use to attach them to a post? Before they were no bigger that then small ones at the bottom of my post.

The Forum software behavior is not clearly defined, AFAIK. At least not publicly.

If you attach an image file and it is above a certain size the software will also generate thumbnail pictures/links in the original post only.

In your case, for some reason the code of the post is sending the browser to a URL on solarpaneltalk.com to get each image by attachment number rather than rendering it inline using the ATTACH tag set.
Not sure what makes the difference.

[SunEagle]

The Forum software behavior is not clearly defined, AFAIK. At least not publicly.

If you attach an image file and it is above a certain size the software will also generate thumbnail pictures/links in the original post only.

In your case, for some reason the code of the post is sending the browser to a URL on solarpaneltalk.com to get each image by attachment number rather than rendering it inline using the ATTACH tag set.
Not sure what makes the difference.

I have to find a way to fix that because it takes up too much page space the way it shows my pictures. Especially if someone responds to my post.

[inetdog]

I have to find a way to fix that because it takes up too much page space the way it shows my pictures. Especially if someone responds to my post.

You can try reducing the number of pixels in the original image using editing software.
Remember the forum software cannot really tell the difference between a small high resolution image and a large low resolution image. It goes entirely by pixel count in each direction.

[lkruper]

You only need a combiner box with over current devices (fuses) if you have more than 2 panels wired in parallel.

I hope you are looking at an MPPT charge controller. You will get more out of your panels going that way then with a PWM type like I did.

Yes, with MPPT the 36v 8a turns into 12v 24a for a 300w panel.

[jimindenver]

I've been using GT panel portables for three years with my travel trailer. The down side is they are bulkier and harder to store than the smaller folding portables. The upside is that they can make a affordable portable portable if you can handle the size. I started with a 230w GT panel I found on craigslist for $50, a simple but functional 20a MPPT controller for $100, a pair of 25 ft 10 gauge MC4 cables for $33, a few short run to the battery with a fuse that I already had and we had more power than we could use in fair weather. I used a pair of pine slates and C-clamps for support, making tracking easy. Lots of power but we had no inverter.

The next year I created two 245w systems the same way. One for a inverter bank, one for the trailer except when we ran larger loads. Then both systems were stacked on the inverter bank. That gave us use of the microwave, coffee pot, hair dryer but the bank and systems were not enough to run even the smallest of A/C. All three systems could but it was a mess of wires, controller and such that I was never going to mount. So I sold them off for enough to buy the system I am going to mount. Until that happens they too will be portable but only flat like they will be mounted. Tracking spoils you and it would be a downer once mounted. Luckily even flat they can run the 5000 BTU A/C on sunny days which is the only time we need it.

One thing I'll add is I could have gone with 300w GT panels to mount. I didn't because they were 45v @8a and I believe you can push the higher voltage/ lower amps to a point that it cost you in the end. I've seen it in comparisons to the systems I have built vs others as well as testing the new system in parallel or series. Lower voltage/ higher amps produce more to the bank. In the case of my 750w system parallel peaks at 55a, series at 48a.

[inetdog]

One thing I'll add is I could have gone with 300w GT panels to mount. I didn't because they were 45v @8a and I believe you can push the higher voltage/ lower amps to a point that it cost you in the end. I've seen it in comparisons to the systems I have built vs others as well as testing the new system in parallel or series. Lower voltage/ higher amps produce more to the bank. In the case of my 750w system parallel peaks at 55a, series at 48a.

Lower efficiency at the higher voltages for your particular CC I wonder?

[jimindenver]

I believe most MPPT controllers are less efficient converting higher voltages down to 12v. I seem to remember a graph by Morningstar with that result.

[Mike90250]

I think the sweet spot is about 5-10V above the desired equalize voltage, thru to about 2x battery voltage. Above that, DC-DC conversion losses start adding up. That has to be balanced against length of wire run & gauge of wire, and complications of Combiner boxes. I now have found that my 165V array, into 66V charging of the batteries, with the 200V controller, runs near the thermal limits of the controller. But I could not get larger wire into the pre-existing conduit. So I live with the thermal losses.