Dual purpose "portable" solar setup for home and RV

[Logan5]

Sunking, I have read many, many posts of yours on this website before ever posting my question here and I respect your knowledge and assistance. However, the "A/C" you are quoting from my post above isn't roof mount AC it is a small portable plug in unit as described in a previous post that you may have missed (or maybe not). It draws less watts than a microwave. I have a hard time believing I can't use that with the right solar/inverter setup.

You are not going to cool a camper with a 5k btu AC unit. much less power that unit from Solar. Most campers have 12k and 18k BTU air conditions due to the lack of insulation. a 5k BTU unit is no where enough, Might not even be enough to remove the humidity created by 2 bodies, much less the heat uptake of direct sun exposure. The weight of the batteries needed would load down your camper and cost more fuel to move said camper around. Still need AC, get a generator.

[Sunking]

I have a hard time believing I can't use that with the right solar/inverter setup.

Sure it can be done if money and weight is no object. Once you learn exactly how much panel wattage and battery it requires you will become a believer. Here is another answer I gave to some guy who wants to run a very small 5000 BTU Window Shaker 6 hours per day.

Panel Wattage = 1600 Watts. $3200
65 Amp MPT Charge Controller. $500
24 Volt 625 AH battery that weighs 900 pounds and cost $2200 every few years.
24 Volt 2000 Watt TSW Inverter. $650
Misc Materials $400
Total Cost Est = $7000

Here is the post. Reply 8. I say goferit. You will learn a lot.

[Tap2112]

Forget Air Conditioning period on Solar. Not going to happen no matter how much sun you have or do not have. Only way to have Air Conditioning is at an RV park with electrical hookup.

Sunking, I have read many, many posts of yours on this website before ever posting my question here and I respect your knowledge and assistance. However, the "A/C" you are quoting from my post above isn't roof mount AC it is a small portable plug in unit as described in a previous post that you may have missed (or maybe not). It draws less watts than a microwave. I have a hard time believing I can't use that with the right solar/inverter setup.

[Sunking]

If we decide to got to the Pacific NW, or another "modest sunlight" area of the country we would simply adjust our usage (and probably wouldn't need the A/C) to accommodate for the lower solar power we were able to generate.

Forget Air Conditioning period on Solar. Not going to happen no matter how much sun you have or do not have. Only way to have Air Conditioning is at an RV park with electrical hookup.

[SunEagle]

By the way, another relevant tidbit, we generally camp in warm, sunny parts of the country. That is not to say every day is sunny of course but we live in California and we camp mostly in the central valley of California where there is always sun except in the dead of winter (and we don't camp much in the winter anyway). So other than a couple of cloudy days on occasion, I would expect our panels to nearly always be collecting sun for the majority of days we are camping due to our location and the time of year we would be using it.

If we decide to got to the Pacific NW, or another "modest sunlight" area of the country we would simply adjust our usage (and probably wouldn't need the A/C) to accommodate for the lower solar power we were able to generate.

I guess where someone camps is a desire for each person. I would rather find a site that has trees to get some shade, especially in the summer. But if you enjoy a lot of sun and no trees then you should have not problem getting enough for your solar panel system.

[Tap2112]

By the way, another relevant tidbit, we generally camp in warm, sunny parts of the country. That is not to say every day is sunny of course but we live in California and we camp mostly in the central valley of California where there is always sun except in the dead of winter (and we don't camp much in the winter anyway). So other than a couple of cloudy days on occasion, I would expect our panels to nearly always be collecting sun for the majority of days we are camping due to our location and the time of year we would be using it.

If we decide to got to the Pacific NW, or another "modest sunlight" area of the country we would simply adjust our usage (and probably wouldn't need the A/C) to accommodate for the lower solar power we were able to generate.

[SunEagle]

SunEagle Very cool! I love to see projects that others have done. I talked with my wife about building portable stands...do yours allow for tilting or are they fixed angle? I considered smaller panels and PWM originally, but after hearing I could get Sharp 165w panels for $40 it pushed me into the MPPT realm due to the higher voltage and the cost savings will pay for the MPPT controller anyway so it ends up being a better option for the same price tag.

In regards to creating similar voltage from the different strings, if that proves to be to challenging or costly due to wire size can I just use multiple, smaller controllers for each string? That's one reason I considered multiple Kid controllers instead of one large controller. Wouldn't that solve any dissimilar voltage problems? The downside to that option is wiring it up and the transferring of electronics to my home system becomes more complicated with a multiple controller setup.

Each panel is mounted to a set of brackets which can be adjust to 3 different angles. I think I got them from HF or Amazon. They are shown in the highest angle but I can lower them to about 28 degrees. The brackets are also screwed into wood bases for stability. I can lower each panel flat to the wood base for storage.

I also thought the smaller 36 cell panels would be easier to move around but then found out that at $2/watt I was wasting money because I could have found a couple of 200 watt panels that would still fit in my RV storage bay and only cost me ~ $1/watt. Live and learn.

[Tap2112]

SunEagle Very cool! I love to see projects that others have done. I talked with my wife about building portable stands...do yours allow for tilting or are they fixed angle? I considered smaller panels and PWM originally, but after hearing I could get Sharp 165w panels for $40 it pushed me into the MPPT realm due to the higher voltage and the cost savings will pay for the MPPT controller anyway so it ends up being a better option for the same price tag.

In regards to creating similar voltage from the different strings, if that proves to be to challenging or costly due to wire size can I just use multiple, smaller controllers for each string? That's one reason I considered multiple Kid controllers instead of one large controller. Wouldn't that solve any dissimilar voltage problems? The downside to that option is wiring it up and the transferring of electronics to my home system becomes more complicated with a multiple controller setup.

[SunEagle]

SunEagle Honestly, I have not plotted them on my roof yet so I don't know how many it will hold. These are 72 cell panels (which is why they would be ideal for a 24v setup) and the dimensions of them are 62.01" x 32.52" so they are approx 3 inches shorter and 5.5 inches narrower than my residential panels. Additionally, my solar buddy suggested I keep at least some of them unmounted to set out away from the RV in case we do park in the shade. If I did 3 strings of 3 in series (with say 6 on the roof and 3 mobile panels - or possibly 3 mounted and 6 mobile) I could at least have use of part of the system while I was parked beneath any shade.

Again, this is all new to me. I don't claim to be coming in with all the answers so maybe there are holes in my plan that are too great to overcome. But, that is why I am inquiring now prior to purchasing any equipment. I have read numerous threads from others who already purchased their equipment - or worse, already installed all their equipment - before coming on here to ask necessary questions. I am trying to do all my due diligence in advance.

Any RV solar system will have limitations and compromises. My hope is to find the sweet spot where it works well for my needs in the RV and yet has portability to transfer all the expensive electronics to my home as a back up (or even continual use) system for my home. If I can do that I can justify the budget for this project. If not, then I will either scale down my RV system significantly or scrap the entire idea and just swap my residential fridge for a Dometic.

Combining a fixed set of panels on your 5th wheel along with a ground mount set might work for you. The problem is getting each of the paralleled sets to produce very similar voltages going to the charge controller. You might need a much bigger wire from the ground mounted set so the voltage drop is insignificant compared to the other 2 sets.

I played with the idea of a roof mounted system for my RV but decided to go with a "portable" ground mount that can be stored inside one of the bays. Of course I messed up by going with 80w & 90w panels along with a PWM CC. Both made my system more costly then needed. But that was about 4 years ago so I learned a lesson.

Here are a couple of pictures of my panels along with a combiner box that I put together and the 30A PWM CC which basically loses about 33% of the panel wattage. I also threw in a couple pix of my RV which my wife would rather I not put holes in the roof.

[Tap2112]

SunEagle Honestly, I have not plotted them on my roof yet so I don't know how many it will hold. These are 72 cell panels (which is why they would be ideal for a 24v setup) and the dimensions of them are 62.01" x 32.52" so they are approx 3 inches shorter and 5.5 inches narrower than my residential panels. Additionally, my solar buddy suggested I keep at least some of them unmounted to set out away from the RV in case we do park in the shade. If I did 3 strings of 3 in series (with say 6 on the roof and 3 mobile panels - or possibly 3 mounted and 6 mobile) I could at least have use of part of the system while I was parked beneath any shade.

Again, this is all new to me. I don't claim to be coming in with all the answers so maybe there are holes in my plan that are too great to overcome. But, that is why I am inquiring now prior to purchasing any equipment. I have read numerous threads from others who already purchased their equipment - or worse, already installed all their equipment - before coming on here to ask necessary questions. I am trying to do all my due diligence in advance.

Any RV solar system will have limitations and compromises. My hope is to find the sweet spot where it works well for my needs in the RV and yet has portability to transfer all the expensive electronics to my home as a back up (or even continual use) system for my home. If I can do that I can justify the budget for this project. If not, then I will either scale down my RV system significantly or scrap the entire idea and just swap my residential fridge for a Dometic.

[SunEagle]

I guess my question is how will you mount those 9 panels on a 5th wheel. Most of the ones I have seen have a lot of stuff on the roof which will make it difficult to get that many panels on without anything putting some shade. Remember any panel that has shade will affect all of the panels in the same string reducing the total output.

You will also have to park in the sun which for many is not comfortable during the summer months or is even available considering the number of trees I see at most of the RV parks.

Just something to consider when you combine solar and RVing.

[Tap2112]

I am not going to answer or help you unless you can answer 1 question I need to know to help you..

During this 1 to 2 month trips, how many days will you be parked without starting the RV engine.

Just to be clear it is a 5th wheel, not a motor-home, but in effect it does get charged when I drive and plug in the 7-pin wire connector.

I cannot tell you how often we would be moving from place to place as we have not mapped out our travel plans yet. I would imagine there will be days when we change locations every 2 days and others where it may be 3-6 days. A good example might be what we are doing this coming weekend for the July 4th holiday. We will be in one place for 6 days. We are obviously staying at an RV park since I currently don't have solar, but this would be a prime example of how we might dry camp instead if we had our own power. I hope that helps.

[Sunking]

I currently have a grid tie system that has worked beautifully for more than 4 years so I began to consider solar for my 5th wheel as well. We are not full timers, more like frequent weekend warriors who are considering a 1-2 month trip in it later this year. .

I am not going to answer or help you unless you can answer 1 question I need to know to help you..

During this 1 to 2 month trips, how many days will you be parked without starting the RV engine.

[Tap2112]

Using Midnite Solar's sizing tool with the specs of these panels I could get away with one Classic 150 if I run 9 panels using 3 in series with 3 parallel. If I go with only 8 panels using 4 in series I exceed the limit of the Classic 200 by a small margin and can't use the 150 or 250 at all. So unless I step down to 6 panels - which may not be enough to charge my batteries based on my usage needs - it seems my only choice is to go with a 9 panel system unless I buy an additional charge controller only to end up with fewer watts, which would be counter productive on both fronts.

[Tap2112]

Any battery bank sized to run on this size system isn't something you want to be moving around . There is always the inherent danger involved with spilling acid and accidently shorting out batteries.

Some people don't realize the cost of removing a RV refer till they go to replace it. I would never give up the propane option.

If I were to choose the option to move the batteries I would buy AGM for that very reason - plus the fact I could spend more on the batt bank if I didn't have to duplicate it. But moving six batteries weighing 75lbs each does not sound like a lot of fun.

Regarding the refrigerator, I completely agree and it was one of several things I used to negotiate hard in my purchase since I bought from a private party. Now I need to find a solution for it which could involve ~$1500 to replace it or $2000 in solar to overcome it and have a nice setup that provides dry camping power as well.