Tilted solar panels vs more flat panels for off road use

[Short_Shot]

Your understanding is flawed.

There is no requirement to use panels in series with an MPPT controller.

I'm not sure why you think this.

 

[Mcgivor]

Your understanding is flawed.

There is no requirement to use panels in series with an MPPT controller.

I'm not sure why you think this.

There is indeed no requirement to use more than one module , provided the individual module's voltage is approximately 1.5 greater that of the nominal battery voltage, this would ,in most cases, be restricted to a 12 or 24V system, the effects of shading however would still apply to a single module .

 

[fratermus]

From your picture I see you have a Ducato/Pro Master. What panels do you have? Looks like it perfectly uses the available space and it's what I'd like to but I can't find a European supplier with many options and decent prices

In the profile pic they were 3x 190w Topoint JTM190-72M and mounted flush between the crossbars of a Vantech Vantech H3 rack (model H3542W) rack. I bought the panels locally off a pallet in 2017 for $0.63/watt if I remember correctly.

Earlier this year I physically destroyed one of the panels and could not find a replacement. They were already NOS ("new old stock", leftovers/overstock) when I bought them years before. 2x (380w) was not not enought to meet my needs so I replaced them with 3x used 250w Trina SS2550P-60 for $0.32/w. I gave away the old panels to a schoolie camper nearby who only had 100w for the whole family. It wasn't pure altruism - I had nowhere to store the pulled panels.

The Trinas were too big to fit between the crossbars and still clear the roof vent so these ride over the rack on front-to-back rails. Not a pretty installation like the first ones, but I don't mind the extra 180w.

Comparing specs I think they are the unlabeled ones Will got from Santan for $50 each. I bought mine locally off a pallet for $78/each ($60 when buying 10 but I couldn't use, carry, or store the other 7).

 

[12kw_2021]

What vehicle/camper do you have? I didn't quit understand how are you placing the panels.

Flexible solar panels are less durable, reason why most of them have less than 5 years of warranty compared to 20-25 of the glass ones. They are also a bit less efficient, 2-3% and more expensive.
But if I'm not tilting them and they'll permanently stay on the roof, glued with such a low profile and low weight, then I think it's worth it, much lower center of gravity and better for off-roading. Also much less drag on the freeway an noise.

Do you guys know of good suppliers of solar panels in Europe? Both rigid and flexible. I'm struggling to find different options.

I have a Sprinter Based 25 foot long rig made in USA.
Here is an image of what someone else did and liked. They started with the panels flat , then shifted to this mode, they are a really pushing things and installed 10Kw of Tesla Model S Batteries , and have a large plastic container with RV antifreeze that they heat and circulate through the batteries.. It's a pretty expensive setup with ~$6k invested in all the hardware, but they claim they can boondock and run the AC for 6 hours each day with no use of the generator which is pretty impressive.

Here is an image of how they mounted the 4 200w panels, I plan on using a similar layout.
Note that the panels are secured with 3M VHB tape, then the feet are coated in a silicon based adhesive to keep water away from the tape . This eliminates the need for any holes in the thin fiberglass roof, and has been done hundreds of times on these rigs. I have a single 280W panel on an older rig for 5 years with this tape, no issues.

 

[Short_Shot]

This is giving me a lot of confidence of running AC in a custom slide in if I can cover the roof in solar. I'm thinking 1200w worth.

Ahh long term dreams.

 

[chrisski]

This is giving me a lot of confidence of running AC in a custom slide in if I can cover the roof in solar. I'm thinking 1200w worth.

Ahh long term dreams.

I'm pretty condident I will have the power to run AC when I'm complete with my 24 volt lithium battery bank.

Now the big problem will be keeping the Inverter and battery cooled in the non-airconditioned pass through storage. My RV living space will be air conditioned, but not the pass through storage. I'm wondering how big a problem this will be. May force me to relocate some equipment.

 

[fratermus]

There have beem many studies done on the subject, a simple Web search will link to them, it's worth the time to study the effects, particularly if shading is an issue in one's situation.

Studying the effects should include both reading & testing with one's particular setup. I've A/B tested the following setups in partial shade (forests while boondocking):

• 2x 100w 18Vmp panels <-- portables
• 3x 190w 36Vmp panels <-- previous mounted array
• 3x 250w 30.1Vmp panels <-- mounted array

While harvest was variable due to changing conditions, there were clear enough differences that I could make an informed decision how to wire each array for partial shade. I will say that there was no absolute winner; parallel worked best on at least one, and series worked better on the other (or others).

For onlookers planning their system I'd say:

• avoid shade*
• if you can't avoid shade use mutliple/separate controllers
• if you can't use multiple controllers then A/B test parallel and series arrangements under your real conditions** to see what works best overall for you. It only takes a few seconds to change the connections.

----
* Not trying to discount the challenges of finding relatively-unshaded spots. I drove about 2 miles further up this mountain in the San Isabel NF to find a clearer spot. Then the Sun Surveyor app helped find the specific spot to park the camper within the general site.
** and series/parallel if one has sufficient even-numbered panels[/S]

{edited to fix rando strikethrough}

 

[chrisski]

Solar panels have an efficiency of about 17-20% Is all the other 80% waster in heat?
If that's the case 600W of solar energy will have 2400W of heat to dissipate, sounds like really a lot of heat that could melt plastic to be honest.
I'm very interested in understanding this.

I was on the roof and measured some temps today.

I found 20% efficient does not mean that 80% extra heat. It just means that things still heat up. I actually found my flexible black solar panels taped to the roof to be slightly hotter than a white roof they mount on, but cooler than other things on the roof like black vents. The Flat glass panels were just barely cooler than the roof.

It's not 2400 watts of heat melting plastic.

==========
Outside temp was 104
Flexible panels mounted on a roof 135
Flat Glass Panels on aluminum Frame over roof Not producing power 129
Flat Glass Panels on aluminum Frame over roof producing power 119
White EDPM Roof 129
Black Plastic Roofing Vent 141

I do think slight angles to the sun made more of a difference to the heat of the Flat glass panels than whether it was producing power.

 

[Boondock Saint]

I'm pretty condident I will have the power to run AC when I'm complete with my 24 volt lithium battery bank.

Now the big problem will be keeping the Inverter and battery cooled in the non-airconditioned pass through storage. My RV living space will be air conditioned, but not the pass through storage. I'm wondering how big a problem this will be. May force me to relocate some equipment.

I'm not coming out of the closet, I'm GOING INTO the closest. Literally. I spent hours at the home depot hell today and picked up some wood, white board, 2x1/2" and 3x1" foil back insulation. I'm sacrificing 1/2 the wardrobe closet space for equipment and using 8 x 120mm fans to circulate air from the bedroom through some ducting made from the foam boards. I'm insulating the 2 large bays to lesson the heat coming in from them.

I just spent days filling in the RV windows in the large slide wall with insulation and made a 1.5" thick insulating wall behind cabinets etc. That already makes a huge difference in the wall temp and overall inside temp.


.

 

[Zwy]

I don’t think its worth it for a vehicle mounted system. I have it and don’t use it.

I don’t want to climb on my roof and spend an hour Adjusting six panels that have six screws each every time I stop. I did find in the late part of the year where the sun is low to the horizon my output was increased up to 40%, which is matched by what the site in my signature block tell me for improved efficiency in the later parts of the year. That same site shows me much less of an improvement in the summer months when the sun is directly overhead. Some of the winds I experienced would be shaking the RV and I did not want my panels extended During those.

I only tilted my panels once. That was my first trip. After that the novelty wore off.

I do put out portable panels and adjust those throughout the day if my roof panels are not giving enough power.

Mine lock and unlock with just holding the button. https://diysolarforum.com/threads/l...ecommendation-for-motorhome.20943/post-261683

Blow the photo up and you can see the locking rod and how the actuator moves it.

 

[chrisski]

Mine lock and unlock with just holding the button. https://diysolarforum.com/threads/l...ecommendation-for-motorhome.20943/post-261683

A how to thread would be nice. I see the strut, but don’t really see how its activated.

 

[Zwy]

A how to thread would be nice. I see the strut, but don’t really see how its activated.

Linear actuator from Windy Nation. If you look closely, there is a milled slot in the angle. The linear actuator pulls the rod back to unlock the assembly, when it gets to end of slot it raises the panel. When lowering, the panel comes down to a saddle stop, then actuator keeps running and pulls the rod back until it kits the internal switch of the actuator and shuts off.

I have an actuator on each side of the camper. The actuators stay in sync due to the internal switch.

 

[Zwy]

A how to thread would be nice. I see the strut, but don’t really see how its activated.

Here is a closeup photo.

And I simply used a trailer connector and cord for the control panel wiring.

 

[Boondock Saint]

Linear actuator from Windy Nation. If you look closely, there is a milled slot in the angle. The linear actuator pulls the rod back to unlock the assembly, when it gets to end of slot it raises the panel. When lowering, the panel comes down to a saddle stop, then actuator keeps running and pulls the rod back until it kits the internal switch of the actuator and shuts off.

I have an actuator on each side of the camper. The actuators stay in sync due to the internal switch.

Can you PLEASE post a comprehensive thread with a parts list and exacting details showing every pics you ever snapped and a general description of how you mounted, measures, attached, contemplated and just every damned thing about this whatsoever?

There's been several threads talking about a tilt mechanism and it would be easier for your investment than if we try to nickel and dime you with questions in perpetuity.


.

 

[Zwy]

Can you PLEASE post a comprehensive thread with a parts list and exacting details showing every pics you ever snapped and a general description of how you mounted, measures, attached, contemplated and just every damned thing about this whatsoever?

There's been several threads talking about a tilt mechanism and it would be easier for your investment than if we try to nickel and dime you with questions in perpetuity.


.

I kinda have a full time job in my business that takes up over 12 hours of my day. I merely put this out there to show how it can be done. I don't use a print to make anything. My friend who is a design engineer tells me it is amazing how I visualize the whole mechanism in my head and just start building it with nary a mistake.

Everything except the linear actuator is fabricated out of just common aluminum angles and flats. Even the hinges.

The length of the slot is the length you need to move the rod that locks the assembly down. As every application and mounting is different, that length will vary. Length and orientation of solar panel itself would affect dimensions dependent on how it was mounted also. There is not a one size fits all.

You do have the choice to purchase the SolarVector which is similar but tilts panels on the side which I didn't have that option. https://www.solarvector.net/

 

[chrisski]

You do have the choice to purchase the SolarVector which is similar but tilts panels on the side which I didn't have that option. https://www.solarvector.net/

Thanks. At $500 per panel, a bit more than I want to spend. Not bad for one panel, but six gets pricey.

 

[filippomasoni]

Here is a closeup photo.

And I simply used a trailer connector and cord for the control panel wiring.

I think this is the simplest and most effective system I've seen so far!
You have one actuator in the middle of each panel right? Because they go up on the longer side.

Do you know roughly how heavy it is?
I'd like to understand how much weight is needed and if it's worth it for the advantage of tilt compared to just "overpanel"

I totally get you don't have time to write a comprehensive thread and that's probably too much to ask. I think I got the basics of it, then of course every system is different based on the space and size of panels, so we all need to do our part.

 

[filippomasoni]

I have a Sprinter Based 25 foot long rig made in USA.
Here is an image of what someone else did and liked. They started with the panels flat , then shifted to this mode, they are a really pushing things and installed 10Kw of Tesla Model S Batteries , and have a large plastic container with RV antifreeze that they heat and circulate through the batteries.. It's a pretty expensive setup with ~$6k invested in all the hardware, but they claim they can boondock and run the AC for 6 hours each day with no use of the generator which is pretty impressive.

Here is an image of how they mounted the 4 200w panels, I plan on using a similar layout.
Note that the panels are secured with 3M VHB tape, then the feet are coated in a silicon based adhesive to keep water away from the tape . This eliminates the need for any holes in the thin fiberglass roof, and has been done hundreds of times on these rigs. I have a single 280W panel on an older rig for 5 years with this tape, no issues.
View attachment 58448

Kudos to them for the tesla system, but too complex in my opinion.

The solar roof in the photo looks really cool, but tilting on both sides aren't they wasting energy on the panels tilted the opposite way of the sun? Although I think since they have stuff that creates shade it makes sense.

I've seen the mounting both with VHB tape and with sikaflex. Isn't it easier to use sikaflex if there's a need for silicon as well after the tape? Or maybe VHB and silicon are just cheaper and easier to source... Also, do you know which type of VHB? I recently used it at home for other purposes and it clearly stated on the box "bot suitable for use on PE, PP, PTFE and silicone". It's the 5952F Although the silicon only seals it.

 

[filippomasoni]

Studying the effects should include both reading & testing with one's particular setup. I've A/B tested the following setups in partial shade (forests while boondocking):

• 2x 100w 18Vmp panels <-- portables
• 3x 190w 36Vmp panels <-- previous mounted array
• 3x 250w 30.1Vmp panels <-- mounted array

While harvest was variable due to changing conditions, there were clear enough differences that I could make an informed decision how to wire each array for partial shade. I will say that there was no absolute winner; parallel worked best on at least one, and series worked better on the other (or others).

For onlookers planning their system I'd say:

• avoid shade*
• if you can't avoid shade use mutliple/separate controllers
• if you can't use multiple controllers then A/B test parallel and series arrangements under your real conditions** to see what works best overall for you. It only takes a few seconds to change the connections.

----
* Not trying to discount the challenges of finding relatively-unshaded spots. I drove about 2 miles further up this mountain in the San Isabel NF to find a clearer spot. Then the Sun Surveyor app helped find the specific spot to park the camper within the general site.
** and series/parallel if one has sufficient even-numbered panels[/S]

{edited to fix rando strikethrough}

So that means it can vary with different kinds of panels and configurations? Or based on the kind of shading we can get?
Sorry if I missed an obvious point in your explanation.

 

[filippomasoni]

I was on the roof and measured some temps today.

I found 20% efficient does not mean that 80% extra heat. It just means that things still heat up. I actually found my flexible black solar panels taped to the roof to be slightly hotter than a white roof they mount on, but cooler than other things on the roof like black vents. The Flat glass panels were just barely cooler than the roof.

It's not 2400 watts of heat melting plastic.

==========
Outside temp was 104
Flexible panels mounted on a roof 135
Flat Glass Panels on aluminum Frame over roof Not producing power 129
Flat Glass Panels on aluminum Frame over roof producing power 119
White EDPM Roof 129
Black Plastic Roofing Vent 141

I do think slight angles to the sun made more of a difference to the heat of the Flat glass panels than whether it was producing power.

That was a hot Sunday!

Interesting, I thought there was a bigger difference. I assume it was sunny with direct light when you measured.

Are the flexible panels directly glued to the EDPM roof? That's such a small difference that's not going to really heat up the camper much more than it would do without them. But it looks like the active glass panels are actually reducing the heat and therefore "cooling of the roof"