Talesun 320 w 60 cell pv panels

[Peter Kuczynski]

Hi Dacian,

I am down to choosing my panels. They will go on a school bus roof top, 4 panels max.

Just wanted some thoughts as to the specs of these panels, as I understand they need to be 24 v and are to be connected in parallel, to work with the Dssr20's. The price if these panels is nice too.

https://www.signaturesolar.us/products/b3cdc6bfa8/2203789000006324264

https://www.signaturesolar.us/products/b3cdc6bfa8/2203789000006324264?variant=2203789000006324264

I am around the Chicago area so shipping need to be US.

Thanks!

Peter

[Dacian Todea]

Peter,

The panels are ideal for charging a 24V battery and price seems OK (normal price).

[Dave McCampbell]

Peter, prices here in Philippines are also around .50 US/watt, but no shipping from local dealers.  So your price for those panels is certainly good especially since they have a 25 year warrantee.  Competition for market share must be fierce these days.  You might want to check on shipping and import duties if this is not a dealer selling already imported panels.  Also, you might want to look at the mounting rails and fittings for mounting them on top of your bus.  We found those here reasonably priced and make an excellent mounting system.

[Peter Kuczynski]

Hi Dave,

Thanks! and tanks you as well Dacian.

I thought since they were so low priced something was up, but it looks like a US shipper. I'll go thru checkout and hopefully nothing bad will happen.

I thought about mounting rails, but so far haven't found any that I like. Feel free to link any you have seen. I am now thinking of simply making my own using exterior lumber, basically 2 2x4x10 or whatever the length turns out to by, lying them long way on the roof, and fastening them down to the roof w steel L brackets to the bus ribs. With wood I'm going to get a little flexibility in how I further want to mount those panels on top . So, since the concern is NOT to become a air-foil when driving down the highway at speeds and a panel shearing off, I'm going to tilt them forward  just slightly to produce a little bit of down force. Otherwise I'm leaving them relatively flat on the roof. I am reading that I'll get maybe 20% loss by not having a perfect angle to the sun, but I figure quantity of panels [4] will overcome quality of poor angles.

I found this link as well that talks about roof mounting panels. For anyone that also has a need to do this.

Peter

[Peter Kuczynski]

Dang, I spoke too sooon...

"No shipping methods are available"

Looks like they dont ship to Chicago area, we'll at least I know what panels and price to look for.

[Dave McCampbell]

Hi Peter.  There should be many sources of solar panels and equipment in the US on the internet.  Competition is fierce so pricing should reflect that and be close.  Just look closely at specs and warrantee.  Those are big panels so minimizing surface area presented to the wind while driving will be important.  We do the same with our 4 200w panels on our cockpit cover on the boat in case of a hurricane.  I recommend you look closely at the aluminum rails and fittings that are available from most resellers.  They really are an excellent and very strong way to fasten panels down.  They are available at all resellers here in the Philippines as they are used on all home installations.  Dave 

[Dave McCampbell]

Peter.  Some thoughts about panel size.  Many panels built these days are for home use, so are of large surface area.  Since force on a surface quadruples as wind speed doubles there is going to be a lot of force on those panels if they get across the wind.  Driving at 60 mph is almost like being in a hurricane.  I have been in 12 in the past 25 years with our boat, so am a bit sensitive about things flying around in strong winds.  You don't want one of any size panel coming loose and ruining your solar system or worse hitting a vehicle behind you.  200w panels is about the biggest I wanted on our boat's cabin top.  I made sure they were angled down in the front and strongly fastened to the top with the aluminum rail systems.  More panels give you more places to fasten them down.  I have 4 200w panels feeding two DSSR20s and it seems to work fine.  Good luck shopping.  Dave

[Dacian Todea]

Dave,

Peter will have the panels mounted on the roof of a school bus flat on the roof so vehicle speed or wind speed will produce almost no force on the panels. Of course panels will need to be properly attached to the vehicle but there are not the same forces as what a ground system PV array is facing like in my case with azimuth angle around 60 to 70 degree where forces on the panels will be orders of magnitude higher.

[Dave McCampbell]

I only mention these things because there will be wind forces on the leading 2" high edges of traditional panels, understandably not as large as if they were perpendicular to the wind.  Also, they should be mounted an inch or two off the bus roof, allowing ventilation underneath, so wind will get under them.  100 mph (65 bus speed plus maybe 35 wind speed) of wind force is not trivial.   Obviously there will be panel size and mounting choices that can reduce the danger of a panel flying off the bus roof, and these should be carefully considered during purchase and installation.  Solar panels don't fly very well.    

[Dacian Todea]

Most panels are designed to deal with 160mph wind speeds at 45 degree so if properly installed there should be no issue with panels flat mounted on the roof.

Of course that will not mean that panels will not need to be properly installed is just that there is no particular problem with flat mounted panels as they are the least affected by wind.

[Peter Kuczynski]

Thank you Dave and Dacian,

I seem to have located panels that will ship to my area. See them here. The cost is .61/watt at 310 watts. Before purchase,I'm going to make a template out of plywood and see how it looks on the roof.

For mounting, I am thinking of using 2x or 4x 12 plastic lumber, on one each side, running length wise on the roof,  and fastening it to the roof with steel L brackets and lag bolts to the ribs of the roof.

I am thinking of placing the panels on the lumber, and tilting them down slightly to add a bit of down force while driving forward at 60-65 mph max speeds.

Because a school bus has a fairly pronounced curve, most fabrications for roof panels mounts that Ive seen are DIY.

Here's a roof picture so you can see what Im faced with.

Peter

[Dave McCampbell]

Agree mounting method is key to a good safe installation, regardless of how much wind panels alone will sustain.  It would be interesting watching one of those big surface area panels supported only by its frame stand up to the equivalent of a Category 5 hurricane.  Panels look to be of good quality and well documented at a reasonable price.

If not using aluminum rail and bracket system, plastic wood better than plain wood.  It is good stuff and will not deteriorate much in UV.  Think you might have to screw panel lower web to plastic wood first then secure wood to bus top.  Clips that grab the entire frame and then could be screwed into the wood would be better.  Also, you might consider constructing your plywood templates so you could use them as mobile covers in case of heavy snow fall or worse big hail storm.  Not much of that to worry about out here in the tropics, so I have not done that.

[Peter Kuczynski]

re: plywood templates so you could use them as mobile covers in case of heavy snow fall or worse big hail storm.

Thanks Dave, for over the winder storage of the bus this is a great idea. I'm hoping one day soon not to be in the great white north, to have to do this.

I will most likely bolt steel angle brackets down to the plastic wood, and screw the panels to it. Chances of shearing steel are closer to nil then aluminum.

I'll start on this project this weekend, looks like the last of the snow will melt by then.

Peter

[Charlie G]

I have older panels that are 305 watt and 72 cell. Pick them up used for 75 bucks in Florida. 

I had a lot of concerns about the panels coming off and all this above mentioned hazards to other drivers. I built a aluminum rack and headed TIG welded. During a hope in hell the rack or panels are coming off my RV. 

Even got my roof vent to work

[Peter Kuczynski]

Thanks Charlie,

That's a nice custom job, no way anything is coming off there. Looks like a air dam up front to route air over the top of the panels. I'm assuming your using Electrodacus as well, 24volt, so 2 panels on each dssr20?  Whats the charge rate on those panels on a clear day. Where did you pick them up ?

[Dave McCampbell]

Charlie, nicely done.  I like the air dam up front to minimize the air pressure and bugs on the panel fronts.  Looks like you bolted the frame to the sides of the panels on the outsides.  How did you attach the frame to the panels along the inside edge of the frame.  I am interested because some day we will probably be doing this.  Dave 

[Charlie G]

Thanks for the recognition guys. It took a lot of work and I don't do any half efforts. 

I've included more photos of the rack I built. During the construction of the inside I had blocked up on the ceiling and some 2x8 material where I knew the leg s of the solar rack would sit. 

The legs consist of a piece of plate with holes pre-drilled, and a 4-in riser so that I have a gap between my solar panels and the roof. This gap serves two functions, 1) to allow air exchanges in hopes the solar panels can cool easier and create better efficiency, 2) And also the air change which would stop any heat gain through my roof into the living quarter. 

The rack is laid out where the solar panels just sit on top of it, and the edge of the box tubing is flush with the edge of the panel. To secure The panel to the rack, I used 1/8" aluminum strapping 4-in wide and pop rivets. The strapping actually serves a purpose of creating a stealth factor, as walking around on the ground it's impossible to know those are solar panels. Everyone just thinks it's a work van with a ladder rack. Lol.  

[Charlie G]

Two more pics. 

And yes I use the 2 panels in paralle l on each DSSR20. These are 72 cell panels, so I don't know if I'm getting a maximum efficiency. I still got a couple things left to redo on my install. I certainly like the SBMS0 because it's so customizable. Maybe this summer I'll get into working with website developers that I use to improve the basic HTML page provided. I want to turn it into a full dashboard, with separate pages for additional data. 

I see a lot of people ask the same questions over and over in these forms, so I appreciate the people that are preparing these additional install guides. It's great work You guys are doing. I've wanted to do a YouTube channel on my build, cuz it's pretty extreme. Who knows maybe someday I'll get to circle back. 

[Charlie G]

One last thing and I'm sorry it's off topic. I noticed somebody was posting that's living down in the Philippines. Are you doing solar down there and running the SBMS0?

I asked because we're looking at building a home in Bicol, and was thinking of solar. Shoot me an email, I'd love to talk more with ya. 

[Charlie G]

Last post. 

For the 2x6 blocks used for mounting the aluminum rack, you can see them in these pics. I used 3/8" lag bolts of each aluminum footer plate for the rack, as week used polyurethane sealant to bond it. It's now impossible to remove. 

Once the rack was mounted without the panels and bonded to the roof, I had the entire van spray foamed inside with closed cell foam. 4" thick, so that really locked up any movement in my framing, as well all the sheeting used. 

[Dave McCampbell]

Nicely done and a major project!  Email on way to you about Bohol.