5,000 watts of solar panels on the roof of a van?

[Inverlyon]

Usually, a design for an application begins by defining the goals of the excercize. In the case of designing a PV system, the types of electrical loads, as well as their size and duration and when they are likely to be incurred are determined or estimated. That helps in system sizing, and choosing other design parameters. For off grid, one of those other sets of design parameters is battery sizing and other parameters associated with any energy storage.

One of several things that estimating likely system loads in the manner described above or similar methods helps with, but does not guarantee, is avoiding system over or under sizing.

Sometimes estimating loads also points out other ways of accomplishing a task. In this case, if the goal is to meet an electrical load, ways may be found to reduce that load and so increase options for meeting that load as well as allowing the load to be met with less expenditure of resources, or make a design actually workable and doable.

Well, a more modest solar system would easily power everything except the air conditioner. Maybe I should take another look at those other options again...

[SunEagle]

I've had some formal training in Title 49 FCR. I know an awful lot of cops, and I have absolutely zero concerns about running afoul of the "roof rack police" in a private motor home with a GVWR of just under 10,000 pounds.



I appreciate your help with the math.

So you're talking about roughly 4,000 amp-hours of batteries for a 5,000 watt solar system. If I'm doing the math right, it would take twenty L16 6-volt batteries to do roughly that, which would weigh over 2,000 pounds and cost $10,000. I'm starting to see the light here...

If you first determine how many watt hours a day you need you can then size your battery system followed by sizing the solar panel system. You are putting the cart before the horse by starting with that 5kw panel size.

[OldSmokey]

I'm a seasoned 25+ year RV'er and an MSEE, take my advice and concede defeat on this one, I've been asked many times by fellow RV'ers on how to run a/c on solar
and it's just not going to happen with current technology given the space and size constraints of a typical RV.
We worked this out a long time ago and you are much better off with a good Honda or Yamaha generator and propane for heat.
my wife and I boondock almost exclusively and I have solar to power average loads, we still need the genny occasionally to recharge with really cloudy conditions.
in hot weather we change our location to cool off if possible ( we camp a lot in AZ and UT ) else we crank up the genny for the night.
I know this is not what you wanted to hear.. but it's reality my friend..

[J.P.M.]

I'm a seasoned 25+ year RV'er and an MSEE, take my advice and concede defeat on this one, I've been asked many times by fellow RV'ers on how to run a/c on solar
and it's just not going to happen with current technology given the space and size constraints of a typical RV.
We worked this out a long time ago and you are much better off with a good Honda or Yamaha generator and propane for heat.
my wife and I boondock almost exclusively and I have solar to power average loads, we still need the genny occasionally to recharge with really cloudy conditions.
in hot weather we change our location to cool off if possible ( we camp a lot in AZ and UT ) else we crank up the genny for the night.
I know this is not what you wanted to hear.. but it's reality my friend..

OP: Listen to the voice of experience here, and not the media hype or peddlers.

Folks who tell you what you may not like or that doesn't fit your version of reality are not necessarily lying to you or trying to hurt your feelings.

[Sunking]

I'm a seasoned 25+ year RV'er and an MSEE, take my advice and concede defeat on this one,

You are wasting your time and breath. This guy wants no part of reality. Let them loose a bunch of money and learn their lesson.

[OldSmokey]

You are wasting your time and breath. This guy wants no part of reality. Let them loose a bunch of money and learn their lesson.

True, unless the OP has deep pockets and a penchant for frivolous projects.

[Boxster1971]

Inverlyon - You will have real issues trying to get to 5000 Watts. The weight alone of such a large system makes it unworkable on a Sprinter van. The maximum roof load allowed on a high roof Sprinter is 330 lbs (150 kg). Exceed that and you risk all sorts of liability issues for exceeding a vehicle manufactures limits.

But there are many vans with 1000 Watt systems. I'm attaching a few photos of examples. The first is a vehicle called Womp that was designed and built by Advanced RV for the owner to spend weeks in the desert at Burning Man a few years ago. It has a small AC unit and a evaporation "swamp" cooler system.

The last photo is the 400 Watt system on my Sprinter van.

Good luck with what every you build.

[Sunking]

True, unless the OP has deep pockets and a penchant for frivolous projects.

Well a van with 5000 watts of panels can do a few things no other van can do

1: Hang Glide. With all that surface area of the panels will act like wings on a Hang Glider. Just drive off a cliff at 40 mph.
2. You very own 4-lane shaded parking lot.

I doubt he has deep pockets as fools are not known to have a lot of money. If they do have money will soon be parted.

[phazaar]

It's easy to see how people get carried away with their condemnation, but most people just won't see things from someone without their experience's perspective. A pretty modest off-grid fixed dwelling would have 5KW of panels; the OP has probably seen this and begun to work out a way to get the same thing in a more mobile format. There's no shame in this. Ideas abound when looking at projects, and none of them are necessarily bad; just perhaps less achievable.

So here's some thoughts on the idea:

1) There's a guy on Youtube running AC in his van off 800Ah and 1KW of panels.

2) Do you even need AC? Loads of Vanlifers in Europe do without by ensuring they have good ventilation (Maxxfan+floor vents), and consider evapourative coolers ('swamp' coolers as you guys refer to them) in dryer climates.

3) If you don't need it every day, you don't need to be able to run it every day. You could install your setup and try to minimise usage. This might reduce your battery requirements, or allow you to run the AC off the vehicle alternator (the Sprinter even has a dual alternator setup you could take advantage of for this). Supposedly its idle is about 1l/hour, so you could cool off the 'hot' 4 hours of the day for only a few dollars.

4) LiFePO4 batteries. Use them. Massive discharge rates ideal for AC, much more power dense, double the usable capacity by rated capacity etc.

5) Semi-flexible panels are about 1kg per 20W - this might reduce your structural load a lot.

6) Following on from 3, lots of ambulances in Europe have AC that will run 'in the back' off the same coolant circuit. Looking into how that's done might give you another way to cool the back - remember it's a really small space compared to a coach-built RV, so can manage on much less cooling.

7) A diesel generator is also a solid option (it's a lot less wasteful than running your engine for cooling, but does require a lot more space. Maybe a worthwhile consideration.

8) Trailers exist. Covering them with panels is an alternative idea.

Maybe somewhere in there is an idea that will help you out. Maybe not. If not, at least I killed a couple of hours of this journey thinking haha!

[SunEagle]

It's easy to see how people get carried away with their condemnation, but most people just won't see things from someone without their experience's perspective. A pretty modest off-grid fixed dwelling would have 5KW of panels; the OP has probably seen this and begun to work out a way to get the same thing in a more mobile format. There's no shame in this. Ideas abound when looking at projects, and none of them are necessarily bad; just perhaps less achievable.

So here's some thoughts on the idea:

1) There's a guy on Youtube running AC in his van off 800Ah and 1KW of panels.

2) Do you even need AC? Loads of Vanlifers in Europe do without by ensuring they have good ventilation (Maxxfan+floor vents), and consider evapourative coolers ('swamp' coolers as you guys refer to them) in dryer climates.

3) If you don't need it every day, you don't need to be able to run it every day. You could install your setup and try to minimise usage. This might reduce your battery requirements, or allow you to run the AC off the vehicle alternator (the Sprinter even has a dual alternator setup you could take advantage of for this). Supposedly its idle is about 1l/hour, so you could cool off the 'hot' 4 hours of the day for only a few dollars.

4) LiFePO4 batteries. Use them. Massive discharge rates ideal for AC, much more power dense, double the usable capacity by rated capacity etc.

5) Semi-flexible panels are about 1kg per 20W - this might reduce your structural load a lot.

6) Following on from 3, lots of ambulances in Europe have AC that will run 'in the back' off the same coolant circuit. Looking into how that's done might give you another way to cool the back - remember it's a really small space compared to a coach-built RV, so can manage on much less cooling.

7) A diesel generator is also a solid option (it's a lot less wasteful than running your engine for cooling, but does require a lot more space. Maybe a worthwhile consideration.

8) Trailers exist. Covering them with panels is an alternative idea.

Maybe somewhere in there is an idea that will help you out. Maybe not. If not, at least I killed a couple of hours of this journey thinking haha!

All good points for the OP to look into.

I guess some of us get a little steamed when a person goes out and makes a big purchase on solar equipment before they even understand the limitations.

IMO, I (and others) may say things to help stop people from making bad decisions which sometimes may be a little harsh.

It is not that we want them to not look into solar power but to at least be smart about it before they open their wallet.

The other part is understand the pure physics of structures, wind loads, and physical limitations to dragging around a large pv array in a small vehicle. You can't put 5 pounds of **** into a 3 pound bag without getting that stuff on your shoes.

[J.P.M.]

[QUOTE=phazaar;n382736]It's easy to see how people get carried away with their condemnation, but most people just won't see things from someone without their experience's perspective. A pretty modest off-grid fixed dwelling would have 5KW of panels; the OP has probably seen this and begun to work out a way to get the same thing in a more mobile format. There's no shame in this. Ideas abound when looking at projects, and none of them are necessarily bad; just perhaps less achievable.]

1.) I wonder if it's less condemnation than a warning. That may well be a matter of perspective. There's no shame in ideas, but it seems that many ideas are not well informed.

2.) Ideas do indeed abound but not all ideas are "good" ideas. Nor, as you write, do all of them have achievable or even possible goals.

3.) However, and more importantly, more than a few ill-informed ideas may even be dangerous.

4.) Seems like the perspective on the worth of comment has changed from valuing straight talk that conveys reliable and useful information based on knowledge and experience in an unvarnished manner to one of making sure everyone gets the warm and fuzzies, their precious feelings not hurt or their fragile and childlike egos not bruised but stroked.

I'd rather have someone with knowledge and experience tell me I'm doing dumb, stupid and ignorant stuff, and in the telling, maybe help keep me out of trouble, than get dumb, stupid and ignorant (non)advice that may well be dangerous from some self centered person who strokes their ego by bloviating crap.

Seems to me that egos can often be impediments to clear and straight communication all around.

5.) Ideas do indeed abound, and there is no shame in communicating ideas. The shame and lack of consideration and respect for others is in not caring much less knowing whether or not you have a clue that what you may be communicating might be poor or even dangerous information.

To your point of no ideas necessarily being bad, the implied converse that all are therefore good is not only not true, but can lead to dangerous assumptions. Conversely to what you write, not all ideas are "good". More than a few of them are just plain dumb. Some are dangerous, with the haze and veil of ignorance often masking the stupidity of an idea.

[phazaar]

IMO, I (and others) may say things to help stop people from making bad decisions which sometimes may be a little harsh.

It is not that we want them to not look into solar power but to at least be smart about it before they open their wallet.

The other part is understand the pure physics of structures, wind loads, and physical limitations to dragging around a large pv array in a small vehicle. You can't put 5 pounds of **** into a 3 pound bag without getting that stuff on your shoes.

No disagreement here, I just feel there are better, more constructive ways to approach a challenging idea than stating things like "This guy wants no part of reality."...

1.) I wonder if it's less condemnation than a warning. That may well be a matter of perspective. There's no shame in ideas, but it seems that many ideas are not well informed.

2.) Ideas do indeed abound but not all ideas are "good" ideas. Nor, as you write, do all of them have achievable or even possible goals.

3.) However, and more importantly, more than a few ill-informed ideas may even be dangerous.

4.) Seems like the perspective on the worth of comment has changed from valuing straight talk that conveys reliable and useful information based on knowledge and experience in an unvarnished manner to one of making sure everyone gets the warm and fuzzies, their precious feelings not hurt or their fragile and childlike egos not bruised but stroked.

I'd rather have someone with knowledge and experience tell me I'm doing dumb, stupid and ignorant stuff, and in the telling, maybe help keep me out of trouble, than get dumb, stupid and ignorant (non)advice that may well be dangerous from some self centered person who strokes their ego by bloviating crap.

Seems to me that egos can often be impediments to clear and straight communication all around.

5.) Ideas do indeed abound, and there is no shame in communicating ideas. The shame and lack of consideration and respect for others is in not caring much less knowing whether or not you have a clue that what you may be communicating might be poor or even dangerous information.

To your point of no ideas necessarily being bad, the implied converse that all are therefore good is not only not true, but can lead to dangerous assumptions. Conversely to what you write, not all ideas are "good". More than a few of them are just plain dumb. Some are dangerous, with the haze and veil of ignorance often masking the stupidity of an idea.

I feel like you're putting an awful lot of words into my mouth, and taking an awful lot of inference from a post that had little. To take a couple of points:

2) I didn't say all of them have achievable or possible goals.

4) Telling someone their idea is dumb doesn't have to be done by being a child and walking out That's not straight-talking.

5) Again, there is no implied converse, because you seem to have missed the qualifier. If I say 'the fridge isn't necessarily cold', it doesn't mean 'the fridge is hot.' It just means that it might not be cold, even though you would expect it to be. The same qualifier also makes the sentence mean that those ideas that are neither good, nor less achievable, are indeed bad ideas.

So, you've turned a sentence about why someone might have a high expectation of what a project can produce, and another about achievability into half a screen of text on concepts you've attempted to read into what was in fact a rather straight-talking post, a bulk of which actually agrees with what was already stated... Irony, I suppose?

[J.P.M.]

No disagreement here, I just feel there are better, more constructive ways to approach a challenging idea than stating things like "This guy wants no part of reality."...



I feel like you're putting an awful lot of words into my mouth, and taking an awful lot of inference from a post that had little. To take a couple of points:

2) I didn't say all of them have achievable or possible goals.

4) Telling someone their idea is dumb doesn't have to be done by being a child and walking out That's not straight-talking.

5) Again, there is no implied converse, because you seem to have missed the qualifier. If I say 'the fridge isn't necessarily cold', it doesn't mean 'the fridge is hot.' It just means that it might not be cold, even though you would expect it to be. The same qualifier also makes the sentence mean that those ideas that are neither good, nor less achievable, are indeed bad ideas.

So, you've turned a sentence about why someone might have a high expectation of what a project can produce, and another about achievability into half a screen of text on concepts you've attempted to read into what was in fact a rather straight-talking post, a bulk of which actually agrees with what was already stated... Irony, I suppose?

Rather than wasting time getting too pedantic and argumentative about it, I'll just say this is a place for opinions, and that opinions vary, and comment that while not agreeing with all your ways of looking at things, add that, IMO only, some opinions reflect reality more than others with those others having a higher probability of being less valid in terms of practicality and safety, and move on.

Lectorem Emptor.

[stupidcrazybus]

Can't and wont say that this can or can not be done however P L E A S E don't be discouraged by the been there done that cant be done crowd. I would suggest the following: figure out how many square feet of area you can create for solar panels, figure out how many watts of solar that will provide you (15w per square foot is a common number) use this number to determine how many solar panels, charge controllers etc. you will need. also use this number to understand what your actual power from solar will be and assess your needs/wants. calculate how this will affect weight and loads on the van. as to batteries I would recommend lithium and specifically LifePo4 type batteries. to a certain extent bigger is always better as it will give you more flexibility. think hard, do your research and be innovative.

[Mike90250]

Can't and wont say that this can or can not be done however P L E A S E don't be discouraged by the been there done that cant be done crowd. I would suggest the following: figure out how many square feet of area you can create for solar panels, figure out how many watts of solar that will provide you (15w per square foot is a common number) use this number to determine how many solar panels, charge controllers etc. you will need. also use this number to understand what your actual power from solar will be and assess your needs/wants. calculate how this will affect weight and loads on the van. as to batteries I would recommend lithium and specifically LifePo4 type batteries. to a certain extent bigger is always better as it will give you more flexibility. think hard, do your research and be innovative.

Do you have any reason to be digging up a 6 month old post ? If you have actual advice to give and want to be responsible for your actions, at least state your "qualifications" as to why your opinion needs to be observed above that of those in the industry. Call us out if we have made a mistake but don't be a weasel and say in effect, forget what the pros say, do what you think will work for you.