Solar Panels and Controller Mounting

Topic: Solar Panels and Controller Mounting (Read 1425 times) previous topic - next topic

Solar Panels and Controller Mounting

May 13, 2013, 08:17:48 pm

I just bought 3 Yingli 280 watt panels (perhaps a fourth) for the roof of our U300. They are huge at 3 x 6.5 feet. The good part is the panel price. $170 each or $0.61/watt for new panels but they are 35.5 volts working or 45 volts open. The mppt charge controller was $600 out of Flagstaff delivered. I looked at the controller that John Haygarth recommended but it would not handle the wattage so I had to go with a different company (MidNite Classic 150) and a couple of hundred more. Does have a nice application for Macs and PCs with a excellent display.

Question: where have others mounted the controller where it's easily visible and looks good? Will probably bring the MC-4 wiring down behind the fridge. Have got the fridge R&R down so it should not take too long.

More info on the panel at: 280W - SOLAR PANELS Manufacturer info at: Power Your Life | Yingli Solar

My best friend has owned a solar engineering firm for many years and is frequently in China at all the factories. I asked him about the quality. Not pushing these panels but for anyone in California, the price seems right. His quote: " Yingli is a well known good quality chinese manufacturer and the price you paid is a high volume wholesale price." Again, I just noticed the ad on Craigslist and thought I would pass it along.

Pierce

Re: Solar Panels and Controller Mounting

Reply #1 – May 14, 2013, 12:39:31 am

mine is on the centre bay wall so the wiring comes straight down behing fridge. Your coach is different .
John H

Re: Solar Panels and Controller Mounting

Reply #2 – October 25, 2013, 02:36:19 pm

Pierce... I am about to pull the pin on buying the 150 Classic MTTB controller because that series wiring is a brilliant idea and I can't find anything better.

My panels (two 240-watt 24vdc nominal) are about the same size as yours. Did you post photos of your actual installation and I missed them? I'm not going to install these until spring so it's not an issue... but I do want to get an idea. You're 6" wider than I am, too.

Craig

Re: Solar Panels and Controller Mounting

Reply #3 – October 25, 2013, 09:11:29 pm

Craig,

Northern Arizona Sun & Wind is still the best price wise and offers excellent tech advice. Solar Electric Power Systems For On & Off Grid Everything is working fine except I have to keep the top food/can door open for ventilation. There are about a million items to consider that take lots of time but in the end, it's worth it. Cost was well under $2K for 1140 potential watts on the roof and all accessories with the exception of batteries I already had.

They had only one customer's unit malfunction and MidNite had another on a plane that day. The controller is made in the U.S. and very helpful when you call them directly.

Yes, series is the way to go with your 24V panels. They will produce about 60 volts wired in series on a cold morning so you could add a couple more panels with everything in series and still have your max volts under the 150 the controller is rated for. PV panel voltage is rated at 77 degrees (panel temp, not ambient) so cold mornings will bring it well above that.

Don't think you will have trouble with space on the roof and could install four like I did without much trouble. I can climb the ladder and walk to the front without stepping on anything. I did have to turn the bat antenna 90 degrees and remove the rear radio antenna. The only clearance problem might be between the AC and the aluminum grab rail (lacking a better word) at the right rear.

Here are the photos but call me when you are ready to go. I still like my installation but it could be done several other ways. Controller readout was just after the sun came up over the mountains so voltage/watts were down as the controller had just switched itself on.

Pierce

Re: Solar Panels and Controller Mounting

Reply #4 – October 25, 2013, 10:33:01 pm

The arrangement of your panels was one thing I wanted to see. Sue would not be happy about losing that can cupboard so I might have to see about that. My Raspberry Pi will have a web site on it for access remotely or locally and I might configure a tablet to get to the readouts.

Thanks for putting these pics up. I'm going to put the 30-Amp MPPT controller in the Streamline Princess for use with its 60-w panels. We'll be selling that in the spring anyway.

Craig

Re: Solar Panels and Controller Mounting

Reply #5 – October 25, 2013, 10:56:13 pm

Craig,

You can remotely mount the display or use your Mac or PC and download the Classic local app found toward the bottom of this page: http://www.midnitesolar.com It's free so you can try it with a tutorial example. Will need a router for WiFi (recommended) or set up with a supplied IP and Ethernet.

Pierce

Re: Solar Panels and Controller Mounting

Reply #6 – October 25, 2013, 11:01:37 pm

Pierce,

Excellent looking installation and you sound very pleased with the results. Thanks for the pics and detailed instructions. With that much solar power it looks like you could stay off the grid for a quite a while. It should pay big dividends as I believe you built your system for about half of what a similar system would cost built by somebody else. However, I would have to locate the controller somewhere else as Cindy would never give up her cupboard drawer space, lol !

Would this system be easy to maintain and are you going to carry extra panels in the event one gets damaged or goes bad for some reason? Are the panels easily removed or replaced for maintenance to the roof?

Thanks,

Jerry aka Murph

Re: Solar Panels and Controller Mounting

Reply #7 – October 26, 2013, 12:22:16 am

Quote from: coastprt – October 25, 2013, 11:01:37 pm

Would this system be easy to maintain and are you going to carry extra panels in the event one gets damaged or goes bad for some reason?

One of the attractions of the "series" connected solar panel grid is that if one goes bad you can take it out of the system and wire around it. All you get is reduced voltage/current (power). In a parallel system you need to more carefully match the panels. When you get a chance you simply buy another panel that fits the space. This is why I'm going to get that same controller and toss the one I have.

Craig

Re: Solar Panels and Controller Mounting

Reply #8 – October 26, 2013, 11:17:45 am

Quote from: coastprt – October 25, 2013, 11:01:37 pm

Pierce,

Excellent looking installation and you sound very pleased with the results. Thanks for the pics and detailed instructions. With that much solar power it looks like you could stay off the grid for a quite a while. It should pay big dividends as I believe you built your system for about half of what a similar system would cost built by somebody else. However, I would have to locate the controller somewhere else as Cindy would never give up her cupboard drawer space, lol !

Would this system be easy to maintain and are you going to carry extra panels in the event one gets damaged or goes bad for some reason? Are the panels easily removed or replaced for maintenance to the roof?

Thanks,

Jerry aka Murph

Jerry,

Thanks.

No, I figure there won't be much to go wrong on the roof unless a tree branch falls on it or we go somewhere there is large hail. We have lots of trees here and a couple of cars have been damaged the last couple of years. A screw gun can pull a panel in less than a minute. I gave the panels a couple of inches clearance on the roof so they would run cooler than if placed flat as higher temperature on the panel means less output. Plus, I wanted to be able to run the wiring through flex plastic conduit where it is in the sun. The electrical connections up top are all the sealed quick connectors and all are inside of the flex conduit. Raising the panels above the roof vs. a flat installation cost about $200 more for the aluminum rectangular tubing and brackets/hardware.

Where the panels could be connected to a controller and a battery on any outside field in five minutes, it can take days or weeks to figure exactly where to run wires, mount components, fireproof the area, etc. Finding the best prices on everything also takes time. Example: the plastic flex conduit was over $3/ft at a hardware store but at an electrical supply company, only $1 a foot. Same with the aluminum rectangular tubing.

The guy that sold us the panels had just finished an installation near Palmdale where they installed 80,000 of the exact same panel. The company has installed 500,000 so far so I'm pretty sure I can get another one from him in case of damage.

Craig makes a good point that it is no problem to take one off line if necessary when wired in series. The MidNite MPPT controller does not care if it sees 18 volts or 150 volts. It automatically makes proper charging voltage out to the batteries. The higher the voltage, the least amount of loss PV panel to controller. I have over 70V in the small compartment behind the controller and can personally tell you it can be shocking to work on.

Pierce

Re: Solar Panels and Controller Mounting

Reply #9 – October 28, 2013, 12:13:39 am

Reading the comments re-series or parallel connections made me jump to AMSOLAR sight as I remembereed some mention of the reasons for one over the other and found this comment.
"A couple of methods exist for overcoming the voltage drop described above. One of them is placing two or more standard 36 cell solar panels in series with each other. This increases the operating voltage of the solar array while keeping the amperage low. This higher voltage is then fed to an MPPT type of charge controller which can step the voltage down and boost the amperage up. This is a viable way to overcome the voltage drop but it comes with some real drawbacks. One is that when you series out two or more solar panels, you run the risk of dramatically reducing the available power if any part of that solar array has shade on it. Another drawback is that the higher the voltage entering the controller, the less efficient the conversion process is to lower the voltage coming out of the controller.

Case in point ... We have two customers who both have the same solar panels and controllers. They ended end up parking side by side in the desert by chance. One of them had four 100 watt solar panels in series and the other had four 100 watt panels in parallel. They decided to see how the two systems compared since they were both in the same climatic conditions. They looked at the charging amperage when both systems were in full sunlight with no shade on the panels and found the guy with the paralleled panels had a slightly higher charging amperage. Then they had their wives monitor the charging amperage while they went up on the roof of their RVs. They stood so that their shadows fell on one out of the four panels on each of the arrays. The guy with the four panels in series had a drop in charging amperage that was very dramatic, almost to the point of having none! The guy with the four panels in parallel found that his charging amperage only fell by one quarter. The three unshaded panels kept on cranking out their power. The message here is that in the world of RVs (where shade can happen depending on where you park and where you place the panels), it is better to have your solar panels wired in parallel."
These guys have been doing Solar for a long time and as our coaches are not usually in the full clear sun when parked they suggest (and automatically install) them in Parallel.
John H

Re: Solar Panels and Controller Mounting

Reply #10 – October 28, 2013, 01:47:20 am

Commercial solar fields run their panels in series up to several hundred volts before they get to the controller. The MidNite Classic 150 is 150 volts max and is the lowest voltage model available. The others are 200 and 250 volts. In talking to both MidNite and Northern Arizona Wind and Sun, they both recommended running the voltage as high as possible but not exceed 150V on a cold morning with our controller. Otherwise, I would have run all in series. The higher the voltage, the less voltage loss between the panels and the controller. In all their testing, this generated the most watts each day.

Here is a link to a forum from Northern Arizona W & S: RV Solar wiring help needed They suggest just the opposite is true about shading.

All the new high wattage panels are 24, 36 or 48 volts. Only the 110 watt or so panels are available in 12V.

Pierce

Re: Solar Panels and Controller Mounting

Reply #11 – October 28, 2013, 09:51:00 am

I don't understand the fixation solar companies seem to have on voltage drop. If you're running 36 volt panels and each one is producing 9 amps max, your voltage at the end of a 40' run thru #12 wire would be 34.9 volts, a loss of 10 watts. Seems insignificant. If that's too much drop then use #10 wire and the drop will be reduced to less than a volt.

Seems like the most advantage would be had by running panels in parallel, if one goes t.u. you can easily disconnect it at the controller rather than having to get on roof and break into all your watertight connections to wire around a panel. As far as partial shading of one or two panels out of an array, parallel seems to hold a clear advantage. Commercial installations don't have to deal with shading, they have the advantage of ideal siting and tilt.

Re: Solar Panels and Controller Mounting

Reply #12 – October 28, 2013, 11:21:46 am

Chuck,

Both my sources quoted earlier sell to both home and RV customers. The manufactures as well as retailers have looked at all possible combinations and seem to like a series installation best. They publish charts with voltage loss, wire size, shading, etc for the best result at the end of the day. In talking to every company, no one recommended a parallel installation. N. Arizona sells almost every brand of controller and besides the tech forum, they have great phone support for any possible question that may come up. Aside from the fact that no other single controller could handle our roof wattage, I was also impressed with the MidNite tech telephone support. They are made in Arlington, Washington and answer the phone quickly with a very knowledgeable tech guy at the other end that will spend as much time as necessary answering questions.

Solar fields are able to install so they can tilt and not worry about shading. On the other hand, large solar panels are dirt cheap now and with the tax advantage, everyone is installing them on homes and RVs. (Tax advantage for RVs as second homes also.) Very few homes are able to tilt the panels or avoid shading sometime in the day.

I am running #10 all the way to the bus behind the controller.

Just before the sun comes up, I have about 70 to 75 (4 36V panels in series/parallel) volts at the controller but really no amps until the sun is on the panels. Once the controller sees the amps it switches on. With a low sun angle and shading on part of each panel once the sun clears the horizon, it still does well and starts charging. Blocking part of a panel only slightly reduces the wattage. I use industry standard MC4 connectors on all connections. They are waterproof but also quick connect so sliding the connectors out of the flex conduit and disconnecting takes very little time.

While I did read individual comments on forums, I based my purchasing as well as installation decisions on the recommendations of large companies that have crunched the numbers with a ton of real world experience thrown in.

Pierce

Re: Solar Panels and Controller Mounting

Reply #13 – October 28, 2013, 11:54:00 am

N Arizona W and Sun is as you may know just a warehouse selling parts, they do not do installs and I have been there in Flagstaff to talk to them before doing my wiring change this year. The "tech" I spoke to on some issues was not quite as informative as I had wanted him to be. I have bought parts from them before and did again but his comment on some items was "we sell a lot of these -----to people so they must be good"???
They have a very busy 'phone bank for selling, that I did see.
Now, when I visited AMSOLAR in Springfield first time (been there 3 times now) Greg and Dave both spent quite a bit of time explaining to me about RV solar, quite a bit different than static panel installs. Greg has (and keeps updating) his own mega panel roof setup on his Winnabago so is very in tune with what the real world is like with RV Solar while travelling, plus they are a VERY "hands on " sales and install place. They started this business ( Greg and Deb) when solar was in its infancy so do know something about it,and, have a very steady business.
I have changed all the wiring on the install they did so that I can minimize out any loss of volts from roof down all the way to batteries, from their #6 to #2, even though #6 is sufficient for my distance of wires. With the set up I have I feel happy with my investment as we have been able to enjoy "non CG " living as most scenery in N America is not next to a camp ground!!
Solar info seems to be a very mixed thought and there seem to be many "experts" out there so this kind of discussion can only help those that follow it. I had absolutely no ideas on what to do at the beginnig and did read a lot of comments online, then decided to go talk to the people whose livelyhood it has been and see what they suggest. AMSOLAR was the place to go for that info, and it is only 400 miles from me.
John H

Re: Solar Panels and Controller Mounting

Reply #14 – October 28, 2013, 12:21:25 pm

John,

I have also heard very good things about AMSolar. My problem in talking with them was that they didn't sell a controller that would handle the wattage of our panels without buying a second controller. Their Tri-Star 60 amp MPPT controller is $540 compared to the MidNite 150s ability to control 96 amps for $610. And our panels need almost all of the 96 amp capacity. So, it was $610 vs $1080 for the two Tri-Star controllers cost plus the extra wires, breakers, cables would have made the two controllers twice as expensive. I also didn't have any extra space for a second controller. The MidNite has a 5 year warranty with a fixed cost for repairs beyond that period.

Our four 280 watt panels only cost $680 total new so was not pleased with the thought of spending twice as much to control them. Hard enough spending $610.

Pierce

Re: Solar Panels and Controller Mounting

Reply #15 – October 28, 2013, 12:35:10 pm

I found 4 grade b sharp 300w panels for 960. I have a150 controller also, so is the final answer series or parallel. Thanksjc

Re: Solar Panels and Controller Mounting

Reply #16 – October 28, 2013, 12:58:45 pm

I had a MidNite 150 shipped to AM Solar and they installed it no problem along with their panels.

Greg and Deb are fine folks. Greg is very familiar with the MidNite designer.

best, paul

Re: Solar Panels and Controller Mounting

Reply #17 – October 28, 2013, 01:20:46 pm

Quote from: hotonthetrail – October 28, 2013, 12:35:10 pm

I found 4 grade b sharp 300w panels for 960. I have a150 controller also, so is the final answer series or parallel. Thanksjc

Since you already have the 150 controller, why not contact the manufacturer for their recommendation for your Sharp 300 watt panels? When I did, they recommended a series/parallel configuration with each set of two panels wired in series and the two sets of panels wired at the bus in parallel.

So, two 36 volt panels wired in series equal 72 volts. The two sets of 72 volt panels are then brought separately to a combining point (bus, bussbar, etc.) behind the controller where they are wired together in parallel, the voltage stays at 72V but the amperage doubles. I could have wired all in series but would have 144 volts. While this is under the 150 volt Classic 150 rating, this is also figured at a 77 degrees panel temperature. On a cold morning, the voltage could exceed 150 volts. While the MidNite 150 is protected from over voltage, it will not turn on until the voltage drops to 150 or less. On a cold winter day, the temperature might never warm up and the controller might never see 150 volts or less. From what I have read, other controllers may not be protected from over voltage and could (and have) fry.

Attached is a four panel series series/parallel installation diagram. In the junction box, the two reds are tied together at a bus connection and the two negatives also tied together. This is exactly how I did our installation.

Pierce

Re: Solar Panels and Controller Mounting

Reply #18 – October 28, 2013, 02:52:02 pm

JC, as you can see by this discussion it all depends on you!!!
Pros and Cons for both ways and with that many watts as long as you have some decent Batteries of good quality either way is good IMHO.
If you have figured out what usage there will be ie, what you total needs in amps are, then if it takes 5 hrs versus 4 hrs to fully charge the system back what the heck? I spent $5k on my system which includes the new AGM batteries from Lifeline and figure it small change to be able to do what we want and go where we want without paying a CG for inferior power and follow their rules!! Last winter alone I bet we saved $1500 by not having to rent a campsite so we had power. Next spring we will be on the road again across Canada and States so another big saving coming up. Now if I could only make my own Diesel fuel!!!!
John H

Re: Solar Panels and Controller Mounting

Reply #19 – October 28, 2013, 03:11:48 pm

Good wording John! What a boring world we would have if we all dressed the same. John makes a great point bout not having to rent a camp site plus paying for inferior power. When he says inferior power, the damage it can do with way too high voltage, spikes, incorrect wiring, can not only be dangerous to you but easily pay for a solar installation if the campground electrics damages your coach equipment.

For those on a tight budget, Craigslist frequently has batteries that will work great on solar setups and for pennies on the dollar. Just takes a little ingenuity.

Now if only they could figure a way to run at least one roof AC from the panels.

Pierce

Re: Solar Panels and Controller Mounting

Reply #20 – October 28, 2013, 03:27:12 pm

Get a small mobile 120VAC air conditioner.

In my 1999 40ft U320 I could close the bath door and cool the salon only. (I use the word "cool" as a fond hope ;o)

Don't know if it would work, but it might exercise the 1200 watts on the roof.

best, paul

Re: Solar Panels and Controller Mounting

Reply #21 – October 28, 2013, 05:03:31 pm

Would the grade b 300w sharps for $960 be a good deal? Thanks jc

Re: Solar Panels and Controller Mounting

Reply #22 – October 28, 2013, 05:58:45 pm

Pierce, I do not worry about ac as we have never used them. I know, strange, but we just use 2 small fans to move the air around. I would not go to an area that is humid or? and need A?C, but wait till another time of year. The noise of them drives Ruth nuts.
I should have a garage sale of the roof a/cs and generator. 3 useless items on our coach
John H

Re: Solar Panels and Controller Mounting

Reply #23 – October 28, 2013, 06:02:51 pm

If you divide the price by the watts, you get the per watt price. In your case, that would be $0.80/watt. Not a bad deal for a good panel. We paid $0.61/watt but had to look for a while. Right after we bought ours, there was an even better deal. You can run down the list and figure the cost per watt but do the research on the panel before you make the deal. The ad should have a closeup of the spec sheet on the back with the model number, voltage and other specs. It pays to be familiar with the terminology but not hard to find websites with all the info with Google. The manufacture of ours, Yingli and Sharp are good companies. Some others have gone out of business and in the event of a problem, it may be hard to get a replacement on warranty or a replacement period. Here is the list from the Sacramento Craigslist for today. Good to do a practice search, calculation and web site for the manufacturer. sacramento all for sale / wanted classifieds "solar panels" - craigslist

Pierce

Re: Solar Panels and Controller Mounting

Reply #24 – October 28, 2013, 06:15:26 pm

John,

Agree about the noise. At least the AC is not off and on like the noisy heater. We are close to Mexico and the Southwest so travel to hot locations a lot in summer. I can't pass up the warm ocean even though I don't swim well. I can take the heat (unless it's really humid) better than Gaylie but she rules the roost when it comes to AC. I love to travel with the window open in cars or the U300 regardless of the temp but...

I remember a trip to San Felipe over spring break. Everyone was playing music, riding four wheelers and not 30 seconds went by without a big firecracker. We ran the air just to drown out the outside noise. Think the movie "Dusk till Dawn" got it's name from the celebration. In Europe in my youth, there was a big dorm room in a youth hostel where at 2am, a couple of guys from a unnamed southern country came in, turned on all the lights and laughed for an hour.

Pierce

Affiliate Notice