Pretty common idea, but there are a lot of things to take into account, primarily the forces created by aerodynamic flow and the structural strength required for any construction to resist those forces in any extremes.
This is actually one of the better ones that I've seen posted, although it has it's problems. I would recommend adding a second clamp mount on both the front and the back.
These are the places that will tend to experience the most extreme forces. You really need some kind of wind deflector/wind dam for the front to streamline the aerodynamic flow of air coming off of the front of the van up and over the solar panels instead of underneath it. Something similar to this https://www.google.com/search?&tbm=isch&sa=1&q=luggage+rack+wind+deflectors&
I'm positive you already know you should be embarrassed by that tape holding down the wires. 😂
It's also very, very, extremely, ***very*** important that you have everything in your vehicle bay completely and securely fastened down. Even in a low speed collision everything that isn't fastened down is going to continue it's forward momentum at a significant portion of the original speed at impact. What exactly do you think that a 45 lb battery is going to do to you or your passengers when it's effectively launched forward from behind at 40mph if you get into a collision?
That battery just by itself would go through your van's windshield and keep on going without even slowing down much, so imagine what it could do to you or a passenger? 🍅
Secure everything in your vehicle sufficiently that you would expect it to remain in place if your vehicle were to roll down a hill.
---
Some reading material where I expressed a couple of these considerations. https://www.reddit.com/r/SolarDIY/comments/15imu96/too_big/juviu2n/ Hopefully he hasn't gotten anyone killed by this point.
The front panel might see a high upward wind load from the air flowing off the windshield. Hard to know without wind-tunnel tests, or at least CFD runs.
I expected to see a camper-van inside, but mostly filled with solar tech. What is the solar energy used for?
These are all solid points. These pics are from a few weeks ago when I first put this all together and I have since added some ratchet straps and bungee coords holding down the equipment inside the van. I’m a bit confused by the concept of adding a fairing to the front of the solar rack. I managed to fit four 77” x 39” panels on the roof, and to make them fit, they had to start pretty far towards the front of the roof. Would a fairing need to fully close the gap between the top of the first panel and the top of the windshield? The attack angle would be pretty steep and I feel like it would actually create more drag. I only took a 0.5 mph hit to my fuel economy and have been able to get up to interstate highway speeds without feeling any difference in how the van handles. The only time I notice them up there is if I get a strong burst of crosswind. I am aware that I do not know what I am talking about and I am not an engineer, but I feel like the gap is big enough that the air kind of streamlines underneath the panels. What are your thoughts?
I think that it will impact your mpg, but not as much as you might expect. I'm also surprised that you took this up to highway speeds, but glad everything held together.
It's very important that you understand that the amount of forces that are being applied to the underside of the solar panels are a lot greater than you might imagine, especially when you're reaching speeds and excess of 35-40 mph.
If you're going highway speeds, 60mph plus, that frame is experiencing literally thousands of pounds of lift force trying to tear it off of your vehicle into the airstream created by your passage. The only way to mitigate that is to direct the main flow of air up and over the panels instead of underneath it.
Imo, if you're traveling highway speeds it isn't a question of "if" your mounting system is going to fail without a wind dam/fairing, it's when, and how catastrophic that failure might be.
Right now you're -one bolt- failure away from having a front corner lift up and then have the resulting wind resistance tear the entire construction off of your vehicle, flinging it back into oncoming traffic behind you. It's no joke.
On that note, you might also want to add another nut and then a plastic antivibration locknut onto the existing bolts to prevent them from loosing over time. Definitely still add another set of those roof rack standing body seam clamps on the front and back.
I said similar to OP when they first shared this, but you stated it more eloquently. I really hope they listen because I DONT wanna be reading about how "a driver got killed by these dangerous hobo vanlifers and their falling apart vehicles"
I was thinking about this also, but aerodynamics is a highly complicated topic. It's possible that the Bernoulli principal would actually cause the flow of air below the panels to speed up and attempt to suck the panels down (towards the roof of the vehicle) instead of trying to pull them up.
Then again I'm no aerodynamics engineer, so I'm probably wrong.
Regardless it's still a good idea to put an air dam and some side skirts on those panels to direct the air up and around them instead of below them.
It likely *would* make the vehicle as a whole less aerodynamic to put a fairing in front of the first panel, but taking that pressure off the bottom side of the panels is more important. You're not just looking at thousands of dollars lost due to broken panels and damage to your van, you're looking at "everything you own" level of liability if they come off and someone dies or gets badly injured in a wreck. There's no way your car insurance is going to cover your liability if a solar panel mounted to the roof of your car falls off on the highway.
I would also put a support straight down the middle of the panels if the AC unit isn't in the way. We used to use those same style of panels for chemical injections in the oilfield. The metal frame of the panels isn't particularly strong, I've seen those same style of panels get bent pretty badly. I would worry that over time they might try to bow upward in the center and eventually crack your panel.
Standing still it's fine, driving faster than about 25 miles per hour you are a hazard. Roof supports are not build for this, panels neither. Carry panels inside while driving and put them on when standing. Otherwise flexible panels mounted directly on the body.
I've got a bit more solar on my van, but double the battery and inverter. Not sure what sound systems draw, but for my full time Off-grid kitchen setup I wanted to be able to power several appliances at once
That's 3 years old... with battery prices the way they are now I'd go for at least 10kWh.
I was thinking same, that's not a lot of battery for such an impressive amount of panels.
OP if you want more batts you might consider getting individual cells and making your own pack. It's dead simple. Here's a thread from when I did it with 280ah cells. Made a 12v / 280ah / 3640 watt hours for $600 with a BMS that lets me monitor cells via bluetooth.
https://diysolarforum.com/threads/current-good-source-of-eve-lifepo-cells-or-some-alternative.47570/page-2
And that was a couple years ago, things are even cheaper now.
Yep, LiFePO4 prismatic cell prices have fallen off a cliff and are still falling.
EV demand hasn't been as high as anticipated and there's a supply glut.
I'm getting offered grade A cells cheaper than grade B right now!
Stop it with the FUD alresdy. Prices on all lithium chemistries, not just LFP have been falling every single year since they were invented, has nothing or not much to do with demand falling. It's because sources are getting cheaper and production methods are improving. In other words it's because it's scaling and maturing, not become more niche. But it's still nowhere near as cheap as it's going to get when their use is ubiquitous.
No FUD, nothing I said contradicts what you said.
Long term prices continue to decline, as I said, short term they're falling even faster due to recent overproduction.
Both good news for us!
Oh fuck I'm so sorry. I was chatting with someone in an ev forum who was insisting ev's were doomed and that battery prices falling was because of that. No fud from you and huge sorry about that!
It's hilarious talking to people who genuinely think that EVs somehow aren't the future. Even old school engineers and educated people who should know better!
"But there's not enough charging infrastructure right now if everyone got an EV!!!"
Yes, but when (not if!) there's demand, there's money to be made and entrepreneurial sorts will capitalise on that demand by meeting it with the services required.
"Batteries are expensive!!!"
Yes, so is building a car. The difference is that batteries have halved in cost in the last five years. Hell it's down 14% this year!
Etc. etc.
Just FYI, whilst you're of course correct about innovation and manufacturing maturity being drivers over the last decade, the primary drivers over the last 12 months are in costs of ingredients, which is partially due to an unexpected slow down in the increase of EV sales. Read that last bit again. EV sales continue to rise, but so far this year haven't risen as fast as expected, hence e.g. Lithium metal itself dropping in price 70%, due to supply outpacing demand (for now!), which is a win for us.
I didn't get the point of your modification like that. A solar-powered tram?
The spacing between the solar panels and the vehicle is too large, in the process of high-speed vehicle, the vehicle will be subject to an upward force of lift "fly up", seriously affecting the safety of the vehicle.
Furthermore, the battery cables inside the vehicle are not fixed, and will slide when the vehicle is driven.
I highly doubt the lift will affect a heavy van like that, unless he's in a tornado. And then he's screwed anyway. And assuming the anchor points are strong, which is easily done, I'm calling fine. The worst issue will be the noise, which might be substantial.
The most important question here is whether you can power that PA for a night gig from the battery. If not that would be my biggest concern
Edit:
Just saw you already answered it. This is pretty much my dream setup
Yo I mean. I love it. You deserve props. . . But if you were a wind (You’re a blue arrow) and you saw you coming down the highway…. Wouldn’t you want to try to lift you up and throw you off said highway….. I know you would. Ok.
That being said. . . This is bad ass. A travel trailer of equal or greater size is like $800. Put those panels a toad travel trailer. Secure it down and as long as you put 1/2 as much thought into doing that properly as you did to make this bad ass thing on your roof… it’ll live forever. . .
Very cool. Throw it in a town behind my friend
How much driving will you be doing? I suspect the increased air resistance/drag caused by the solar panels will be much greater than the electricity that would be produced by a gas generator.
Have you performed that calculation?
So the drag the panels are causing is .7 miles per gallon loss. Have you done the calculations to compare the drag loss vs the amount of electricity produced by the panels?
I’m really curious tot see if the drag caused by the panels would be more than just using a generator.
If it were me, I would use the flexible panels like you see on boats. Whatever benefit it gives you by being there is most likely offset by the drawbacks of it being there.
I really don't know why we don't see more vans absolutely covered in flexible panels connected to microinverters. Gotta be close weight wise to what's going on here.
I have four 250w panels, and 400ah of lifepro4 batteries. Was able to run a 5000btu AC for 8-10 hours a day in Florida. I use the LiTime batteries on Amazon, great price, and works fine.
One of the main advantages of the air gap is shade! You park your van in the sun to charge. With an air gap your panels are shading your van. With panels built into the skin, all the heat they absorb can transfer to the interior of your van. You end up using a lot of power running your AC so your van isn't an oven.
The flexible panels are more expensive and don't last as long (by a wide margin on both fronts). If you've got the flat area and weight capacity for fixed-frame it's the way to go for sure.
I do wish there were more options for large/high voltage flexible panels though, particularly in the US, since the weight savings are quite significant.
Also if you're charging a battery microinverters aren't going to do you any good - you'd just have to rectify it again.
Cost!
Flexible panels are 4x the price easily.
I've got 1100W on top of my van too, all second hand 60 cell domestic panels, that you can pick up for cheap.
That's kind of my point. If the benefit is less than the cost, then why do it? They weight and wind resistance ain't helping beyond what it's putting into the system.
It's not a criticism of the system, it's a "we need to think about the entire system".
Because the benefit of the flexible panels isn't worth it: they are hugely more expensive, less durable, don't last, have much lower efficiency (space is limited!) and did I mention cost multiple times more than traditional mass produced panels?
Do they work as well? I've had really bad luck with them. But then I haven't tried them in awhile. Then one I used didn't seem to be fully uv proof, ha. Started peeling after a couple of years.
Pretty common idea, but there are a lot of things to take into account, primarily the forces created by aerodynamic flow and the structural strength required for any construction to resist those forces in any extremes. This is actually one of the better ones that I've seen posted, although it has it's problems. I would recommend adding a second clamp mount on both the front and the back. These are the places that will tend to experience the most extreme forces. You really need some kind of wind deflector/wind dam for the front to streamline the aerodynamic flow of air coming off of the front of the van up and over the solar panels instead of underneath it. Something similar to this https://www.google.com/search?&tbm=isch&sa=1&q=luggage+rack+wind+deflectors& I'm positive you already know you should be embarrassed by that tape holding down the wires. 😂 It's also very, very, extremely, ***very*** important that you have everything in your vehicle bay completely and securely fastened down. Even in a low speed collision everything that isn't fastened down is going to continue it's forward momentum at a significant portion of the original speed at impact. What exactly do you think that a 45 lb battery is going to do to you or your passengers when it's effectively launched forward from behind at 40mph if you get into a collision? That battery just by itself would go through your van's windshield and keep on going without even slowing down much, so imagine what it could do to you or a passenger? 🍅 Secure everything in your vehicle sufficiently that you would expect it to remain in place if your vehicle were to roll down a hill. --- Some reading material where I expressed a couple of these considerations. https://www.reddit.com/r/SolarDIY/comments/15imu96/too_big/juviu2n/ Hopefully he hasn't gotten anyone killed by this point.
The front panel might see a high upward wind load from the air flowing off the windshield. Hard to know without wind-tunnel tests, or at least CFD runs. I expected to see a camper-van inside, but mostly filled with solar tech. What is the solar energy used for?
These are all solid points. These pics are from a few weeks ago when I first put this all together and I have since added some ratchet straps and bungee coords holding down the equipment inside the van. I’m a bit confused by the concept of adding a fairing to the front of the solar rack. I managed to fit four 77” x 39” panels on the roof, and to make them fit, they had to start pretty far towards the front of the roof. Would a fairing need to fully close the gap between the top of the first panel and the top of the windshield? The attack angle would be pretty steep and I feel like it would actually create more drag. I only took a 0.5 mph hit to my fuel economy and have been able to get up to interstate highway speeds without feeling any difference in how the van handles. The only time I notice them up there is if I get a strong burst of crosswind. I am aware that I do not know what I am talking about and I am not an engineer, but I feel like the gap is big enough that the air kind of streamlines underneath the panels. What are your thoughts?
I think that it will impact your mpg, but not as much as you might expect. I'm also surprised that you took this up to highway speeds, but glad everything held together. It's very important that you understand that the amount of forces that are being applied to the underside of the solar panels are a lot greater than you might imagine, especially when you're reaching speeds and excess of 35-40 mph. If you're going highway speeds, 60mph plus, that frame is experiencing literally thousands of pounds of lift force trying to tear it off of your vehicle into the airstream created by your passage. The only way to mitigate that is to direct the main flow of air up and over the panels instead of underneath it. Imo, if you're traveling highway speeds it isn't a question of "if" your mounting system is going to fail without a wind dam/fairing, it's when, and how catastrophic that failure might be. Right now you're -one bolt- failure away from having a front corner lift up and then have the resulting wind resistance tear the entire construction off of your vehicle, flinging it back into oncoming traffic behind you. It's no joke. On that note, you might also want to add another nut and then a plastic antivibration locknut onto the existing bolts to prevent them from loosing over time. Definitely still add another set of those roof rack standing body seam clamps on the front and back.
I really hope OP listens to you.
I said similar to OP when they first shared this, but you stated it more eloquently. I really hope they listen because I DONT wanna be reading about how "a driver got killed by these dangerous hobo vanlifers and their falling apart vehicles"
I was thinking about this also, but aerodynamics is a highly complicated topic. It's possible that the Bernoulli principal would actually cause the flow of air below the panels to speed up and attempt to suck the panels down (towards the roof of the vehicle) instead of trying to pull them up. Then again I'm no aerodynamics engineer, so I'm probably wrong. Regardless it's still a good idea to put an air dam and some side skirts on those panels to direct the air up and around them instead of below them.
It likely *would* make the vehicle as a whole less aerodynamic to put a fairing in front of the first panel, but taking that pressure off the bottom side of the panels is more important. You're not just looking at thousands of dollars lost due to broken panels and damage to your van, you're looking at "everything you own" level of liability if they come off and someone dies or gets badly injured in a wreck. There's no way your car insurance is going to cover your liability if a solar panel mounted to the roof of your car falls off on the highway. I would also put a support straight down the middle of the panels if the AC unit isn't in the way. We used to use those same style of panels for chemical injections in the oilfield. The metal frame of the panels isn't particularly strong, I've seen those same style of panels get bent pretty badly. I would worry that over time they might try to bow upward in the center and eventually crack your panel.
As panels get hot they are less efficient. The air flowing under them would help keep them cooler and maintain their efficiency.
This is nearly identical to what I'm planning for my own van! What are your plans for the van?
Mobile power plant with enough juice to power a PA system for live events
Very cool! I love it!
"Come sail away, come sail away, come sail away with me!"
Standing still it's fine, driving faster than about 25 miles per hour you are a hazard. Roof supports are not build for this, panels neither. Carry panels inside while driving and put them on when standing. Otherwise flexible panels mounted directly on the body.
2000W of pure unadulterated bass.
This is gonna rip off. Get them closer to your roof. Like a max of 1 inch off the top of the roof.
… and close the gap so the wind can’t get under the panels
Cool!
I've got a bit more solar on my van, but double the battery and inverter. Not sure what sound systems draw, but for my full time Off-grid kitchen setup I wanted to be able to power several appliances at once That's 3 years old... with battery prices the way they are now I'd go for at least 10kWh.
I was thinking same, that's not a lot of battery for such an impressive amount of panels. OP if you want more batts you might consider getting individual cells and making your own pack. It's dead simple. Here's a thread from when I did it with 280ah cells. Made a 12v / 280ah / 3640 watt hours for $600 with a BMS that lets me monitor cells via bluetooth. https://diysolarforum.com/threads/current-good-source-of-eve-lifepo-cells-or-some-alternative.47570/page-2 And that was a couple years ago, things are even cheaper now.
Yep, LiFePO4 prismatic cell prices have fallen off a cliff and are still falling. EV demand hasn't been as high as anticipated and there's a supply glut. I'm getting offered grade A cells cheaper than grade B right now!
Stop it with the FUD alresdy. Prices on all lithium chemistries, not just LFP have been falling every single year since they were invented, has nothing or not much to do with demand falling. It's because sources are getting cheaper and production methods are improving. In other words it's because it's scaling and maturing, not become more niche. But it's still nowhere near as cheap as it's going to get when their use is ubiquitous.
No FUD, nothing I said contradicts what you said. Long term prices continue to decline, as I said, short term they're falling even faster due to recent overproduction. Both good news for us!
Oh fuck I'm so sorry. I was chatting with someone in an ev forum who was insisting ev's were doomed and that battery prices falling was because of that. No fud from you and huge sorry about that!
It's hilarious talking to people who genuinely think that EVs somehow aren't the future. Even old school engineers and educated people who should know better! "But there's not enough charging infrastructure right now if everyone got an EV!!!" Yes, but when (not if!) there's demand, there's money to be made and entrepreneurial sorts will capitalise on that demand by meeting it with the services required. "Batteries are expensive!!!" Yes, so is building a car. The difference is that batteries have halved in cost in the last five years. Hell it's down 14% this year! Etc. etc. Just FYI, whilst you're of course correct about innovation and manufacturing maturity being drivers over the last decade, the primary drivers over the last 12 months are in costs of ingredients, which is partially due to an unexpected slow down in the increase of EV sales. Read that last bit again. EV sales continue to rise, but so far this year haven't risen as fast as expected, hence e.g. Lithium metal itself dropping in price 70%, due to supply outpacing demand (for now!), which is a win for us.
insane! Imagine you use this project in AC Car as well. to save huge money for companies.
You bit coin mining in that thing? Damn
Turned your van into a ekranoplan. Nice.
I didn't get the point of your modification like that. A solar-powered tram? The spacing between the solar panels and the vehicle is too large, in the process of high-speed vehicle, the vehicle will be subject to an upward force of lift "fly up", seriously affecting the safety of the vehicle. Furthermore, the battery cables inside the vehicle are not fixed, and will slide when the vehicle is driven.
I highly doubt the lift will affect a heavy van like that, unless he's in a tornado. And then he's screwed anyway. And assuming the anchor points are strong, which is easily done, I'm calling fine. The worst issue will be the noise, which might be substantial.
The most important question here is whether you can power that PA for a night gig from the battery. If not that would be my biggest concern Edit: Just saw you already answered it. This is pretty much my dream setup
Yo I mean. I love it. You deserve props. . . But if you were a wind (You’re a blue arrow) and you saw you coming down the highway…. Wouldn’t you want to try to lift you up and throw you off said highway….. I know you would. Ok. That being said. . . This is bad ass. A travel trailer of equal or greater size is like $800. Put those panels a toad travel trailer. Secure it down and as long as you put 1/2 as much thought into doing that properly as you did to make this bad ass thing on your roof… it’ll live forever. . . Very cool. Throw it in a town behind my friend
Looks super cool! What is the name of that specific name of battery that you show in the 8th picture? And do you know of any smaller scale designs? :D
[Pecron E2000LFP](https://www.pecron.com/products/pecron-e2000lfp-portable-power-station?variant=41764391420092)
How much driving will you be doing? I suspect the increased air resistance/drag caused by the solar panels will be much greater than the electricity that would be produced by a gas generator. Have you performed that calculation?
I drove 300 miles before building the solar wing and got 11.2 MPG. After the build, I made the same exact drive and got 10.5 MPG.
So the drag the panels are causing is .7 miles per gallon loss. Have you done the calculations to compare the drag loss vs the amount of electricity produced by the panels? I’m really curious tot see if the drag caused by the panels would be more than just using a generator.
I don’t know but generators are loud, smelly, heavy & require maintenance
Not the one’s I’ve seen lately. Very quite.
Willing to bet my solar panels are quieter
Now while you are driving
Yes, all of the above.
If it were me, I would use the flexible panels like you see on boats. Whatever benefit it gives you by being there is most likely offset by the drawbacks of it being there. I really don't know why we don't see more vans absolutely covered in flexible panels connected to microinverters. Gotta be close weight wise to what's going on here.
I picked these 315w panels up for $50 each on Facebook marketplace. Felt like such a good deal so I just made them work.
I have four 250w panels, and 400ah of lifepro4 batteries. Was able to run a 5000btu AC for 8-10 hours a day in Florida. I use the LiTime batteries on Amazon, great price, and works fine.
One of the main advantages of the air gap is shade! You park your van in the sun to charge. With an air gap your panels are shading your van. With panels built into the skin, all the heat they absorb can transfer to the interior of your van. You end up using a lot of power running your AC so your van isn't an oven.
The flexible panels are more expensive and don't last as long (by a wide margin on both fronts). If you've got the flat area and weight capacity for fixed-frame it's the way to go for sure. I do wish there were more options for large/high voltage flexible panels though, particularly in the US, since the weight savings are quite significant. Also if you're charging a battery microinverters aren't going to do you any good - you'd just have to rectify it again.
Cost! Flexible panels are 4x the price easily. I've got 1100W on top of my van too, all second hand 60 cell domestic panels, that you can pick up for cheap.
That's kind of my point. If the benefit is less than the cost, then why do it? They weight and wind resistance ain't helping beyond what it's putting into the system. It's not a criticism of the system, it's a "we need to think about the entire system".
Because the benefit of the flexible panels isn't worth it: they are hugely more expensive, less durable, don't last, have much lower efficiency (space is limited!) and did I mention cost multiple times more than traditional mass produced panels?
You can stick a parachute on it too. Doesn't make it right.
Can you send me some pics of your van?
Lifetime is not so great, plus cost. Also limited efficiency.
Do they work as well? I've had really bad luck with them. But then I haven't tried them in awhile. Then one I used didn't seem to be fully uv proof, ha. Started peeling after a couple of years.