Solar, round 3

[Nwcid]

This very long post is mostly meant to inform and not really ask any questions. If I am missing something please let me know.

Today I am working on my 3rd solar system. We are mainly boondocks, and our needs have changed over the years.

My first system was 2 - 6v Trojan T105 batteries, a 1000 watt Xantrex inverter with 20 amp charger and 2 flexible panels that put out 130 watts each (if I recall correctly) using a 45 amp Morningstar MPPT.

These panels were about 1.5' wide and I think about 15' long. They came with a sticky back that you placed right on the roof.

After a couple of uses in poor conditions I added 2 more panels and 2 more batteries. This RV was a converted cargo trailer so the power demand were LED lights, Fantastic fans and charging things like computers and phones. I had no additional source of charging.

This system served me well for about 2-3 years.

I then got a deal a nice car hauler with living quarters but no water. It did have a built in generator. I move the solar system/batteries/inverter to the second tailer where they were still going strong when I sold it about 3 years later.

This brings me up to my current RV which is a 40' toy hauler. I decided to start fresh and build a whole new system. The base of my system is a Magnum MSH3012 wired into 1 leg of my RV. This provides power for our daily lives including high draw cooking appliances. I remote work so it also runs all of my office stuff. This is hooked into 6 - 6v AGM batteries with a total of 675 AH. The inverter is on all the time when it is not in storage for winter.

Our average power draw during the day while I am working is between 25-30 amps. At night with a fan on and CPAP we are typically drawing just over 10 amps.

Now for the solar part. I am using a Magnum PT-100 controller since it integrates with the invert and ARC-50. I did a lot of debating between flexible and solid panels. Since I had good luck with my previous panels I chose to go flexible again. The panels did not have mounting instructions so I used an "X" of Dicor in the middle of the panel and then sealed around the edge to keep water out from underneath.

I originally purchased 4 - 160 watt Renogy panels which at peak is just over 30 amps. A couple of months later, panels were on sale and I added 2 more for total of 6 putting me at 50 amps peak. The first year I had these I routinely saw mid-40's amp. Last year I saw some decrease in performance and assumed they were dirty so I washed them. We also had record breaking heat so I assumed that was degrading performance.

Jump to this year we had the opportunity to pull the RV out and winter in AZ. I had a chance to test my panels. Only 2 were putting out full output and the others were way under performing with 1 not even putting out 1 amp. I contacted the company and after sharing results and images they said I had mounted the panels wrong and heat caused them to delaminate. I searched their website for instructions and found none. They did send me a link saying not to mount them in the way I did and some options. Interesting side note, my bother just got a new TT with "factory" solar and they have 2 of the 100 watt Renogy panels mounted the exact same way I did.......

Renogy did offer me a reasonable % discount if I wanted to purchase new panels. Feeling frustrated I did a lot of looking on "best bang for my buck" for new panels. I looked at 6-10 panel systems ranging from 65 amps to 100 amps that were compatible with my PT-100. Dollar/Watt all came out similar so I ended up buying 8 - 175 watt Renogy Flexible panels with 76.7 amp output.

I looked at a few different ways to mount them. One way Renogy recommend was to run strips of Dicor along the short side to allow heat to escape. I could be wrong but I do not see that making enough difference in heat and I wanted more space.

I looked at some different types of aluminum stand offs. One suggestion I found online used corrugated plastic under the panel and was the main way I was looking. Due to the shape of the panels it would have created a lot of waste and a large cost with 8 panels. Living on a ranch dad reminded me we had bunch of galvanized studs in one of the outbuildings.

If you had to buy new this is likely not a very cheap way to mount panels. For me I was able to do my whole project without a trip to town. I will need to replenish some supplies though.

I am sure I over built this system, however I am hoping for the best, preparing for the worst. I made a "frame" that has channel the mounts to the trailer roof and then the stud lays in the channel. I used sheet metal screws in locations I can remove them with the panels attached. Each panel has 6 holes in them. My plan is to attach them to the studs with tin roofing screws. I do have some concerns about them "vibrating" loose, if they do I will move to some kind of stud system. Again this is why I build the frames like I did.

Even though the panels are only 26.5" wide the center sags without support. I added a 3rd rail just to keep the panels from sagging.

Here are some pics. I have 2 of the old panels up as a test. I only have a couple of my new panels now, the rest arrive on Monday.

[TucsonAZ]

It's been very interesting how much many of my favorite hobbies have changed over the past 5 years, solar and astronomy being two of them.



The system you have is rooted in older tech I would say, SLA batteries as an example are really a great value with the direction LifePo4 has gone. Much of the China stuff is so well made it's not worth messing with the "better quality" brands. For example, I'm selling all of my Midnite, Outback and so on, top of the line stuff from not long ago while I still can and buying cheap China stuff to replace it.



Also, I would personally never mount a panel without 3-4 inches of space below it. I did this one, 2 inches of space with an inch of airflow under the frame and it was so hot under the panels it pealed the paint. I would also only use grid tie panels, the panel tech has gotten AMAZING, 1-2 panels now would replace all of those.



PS Renogy makes trash, good support for horrible products.

[Camper25]

Tucson AZ, what brand of panels if you were ready to buy new one's today? I need 600 watts asap.

Note... I would never buy flexible panels.

[Nwcid]

Originally Posted by TucsonAZ

It's been very interesting how much many of my favorite hobbies have changed over the past 5 years, solar and astronomy being two of them.

For sure.

The system you have is rooted in older tech I would say, SLA batteries as an example are really a great value with the direction LifePo4 has gone. Much of the China stuff is so well made it's not worth messing with the "better quality" brands. For example, I'm selling all of my Midnite, Outback and so on, top of the line stuff from not long ago while I still can and buying cheap China stuff to replace it.

Well my system is in it's 4th year now, so it is "older". I looked at lithium and wanted lithium but the price point was not there. I paid $1300 shipped for 675 AH (yes less usable than lithium) and at the time a "good deal" was $950 for 100 AH of lithium. I spent a month doing pro/con and budgeting.

In my next rig I will be doing lithium. As you said, things are changing quickly.

Also, I would personally never mount a panel without 3-4 inches of space below it. I did this one, 2 inches of space with an inch of airflow under the frame and it was so hot under the panels it pealed the paint. I would also only use grid tie panels, the panel tech has gotten AMAZING, 1-2 panels now would replace all of those.

Again, I mounted these units in the same way previous panels were designed to be mounted. I do not recall the brand, but they had adhesive built into the back of the panel intended to be direct mounted. They were still going strong at 6 years of use.

For my next RV I will be looking at different panels.

Not that it makes it right, but my bothers rv with "factory installed" panels has flexible panels Dicor mounted directly to the roof.

PS Renogy makes trash, good support for horrible products.

This post was really to inform others of my experiences. This is a patch to an existing system. My plan is to get a new unit in the next year or 2 and I will do a different set up for that.

[Nwcid]

Here is the completed project.