My parents are moving into a parked 50 amp RV inside 11 acres to be near my aging grandparents. Please help design their off grid solar system?

[chickencoops]

My grandpa is gifting this 11 acres to my dad and grandpa lives on the adjacent property. My dad expects to live there for a few years and he eventually wants to take the solar system back to his house. I have been put in charge to do the research and I'm trying my best but this is beyond my ability to design. That is why I'm here!

This is what I have so far:

The panels themselves mounted on those ballasted ground plastic mounts. No digging or any extensive work!

The inverter + batteries going to be housed in an insulated ventilated metal shed that's going to be next to the RV.

Inverter/Charger: I was completely overwhelmed by all the options but it looks like Victron is time-tested. I was thinking the 48V Quatrro because of the dual AC inputs. Solar + generator

Sunlight: Extremely good view of the eastern sun with no shade.

Location: Pacific Northwest. Lots of cloudy and overcast days.

50amp RV: 2 AC's /electric heater/12V Refrigerator/Microwave.

Battery Bank: I can't figure out what they would need!

I have no clear idea of how much is too much or too little. There is no frame of reference. Quattro 10kVA too little or too much? or should it be 2x Quattro 10kVA? and how many LiFePO4 batteries?

Is 48V inverter the right call for this application?

They are going to need an electrician, so labor is also factor in overall cost.

Anyone done anything similar to this? Any brands or suppliers or "kits" that I should look into?

 

[Daddy Tanuki]

tell them to get a "kill a watt" meter and find out how much power they actually use in the camper over a couple of days minimum. put one on the fridge and one on the other main cicuits. for the a/c you will need to find out the actual nameplate rating and use that for your audit as they are two big for a kill a watt to measure.

once you know how much they will use, you can calculate out the battery size, and from there the requirements for your solar panels.

 

[Tomthumb62]

Is 48V inverter the right call for this application?

Very likely yes. If they only need to run basic 12v loads like water pump and lights, then 48v is overkill. If they want to run more typical rv loads such as air conditioner then 48v yes. If they want to run multiple high load devices like running the coffee maker, microwave and toaster oven all at once, then yes 48v is the way to go.

I’ll bow out for your other questions as more qualified people can answer those. Good luck!

 

[Daddy Tanuki]

and yes any system running two a/c's will need a 48 volt inverter. look at magnum, victron, outback, trace(now xantex or schineider bought them i think). those are your time tested big four. look at low frequency inverter chargers. they use a more robust design thta can handle larger inductive loads then the Chinese craptastic junk.

 

[chickencoops]

The "kill a watt" meter is a good idea. Thanks

for the a/c you will need to find out the actual nameplate rating and use that for your audit as they are two big for a kill a watt to measure.

The A/C are going to massive loads. Summers are going to be hot and I imagine there being days where it's run for 12 hours.

Very likely yes. If they only need to run basic 12v loads like water pump and lights, then 48v is overkill. If they want to run more typical rv loads such as air conditioner then 48v yes. If they want to run multiple high load devices like running the coffee maker, microwave and toaster oven all at once, then yes 48v is the way to go.

Thanks for confirming! Yes all the typical rv loads. This is going to be full time through summers and winters and everything in between!

look at magnum, victron, outback, trace(now xantex or schineider bought them i think). those are your time tested big four. look at low frequency inverter chargers. they use a more robust design thta can handle larger inductive loads then the Chinese craptastic junk.

Makes perfect sense. They would want a reliable system that can handle the loads! Thanks for the names of the big four. Any recommendations on any trusted shops to shop at?

 

[Tomthumb62]

2 AC's /electric heater/12V Refrigerator/Microwave.

Running two A/C’s from solar/battery can be done, but you need a lotttta panels. And if you need to run it after peak solar production hours, you need a lot of battery.

Same goes for electric heat, but even worse because solar production in the PNW in winter is almost nonexistent. So that means either switch to propane heat or go on the grid.

By almost nonexistent in winter, I mean you’ll get some solar production but no where even remotely close enough to heat an RV unless you put up 11 acres of panels. Maybe more. I didn’t do any math lol.

The suggestion for a killawatt meter is excellent

 

[Daddy Tanuki]

these two come to mind of good vendors that back the products they sell

northern arizona wind and solar (NAWS)
missouri wind and solar (ebay)( thought they have leaned harder into wind lately and less on solar. but they were good before.
will (forum owner) also i believe has some affilitate links for gear he has tested on youtube that is reasonable. not neccesarily as good as the top four, but not bad, and much cheaper of course.

victron is hard to beat due to their software, and communications between devices. but you have to buy all victron if you want that. magnum is the same way but not quite as large of options. i do not know about outback or the "schineider group" most outback systems i have seen are teamed with midnight solar. just my observations.

none of them are cheap, and they all have different levels of scalability. double check all victron specs as it is aimed primarily at europe, asutraila etc. so the voltages are often times different though this is slowly changing. some of their gear is not NEC compliant which can cause issues as well. all of magnums gear is NEC/UL compliant as they started out feeding the US market.

victron offers larger units which in some cases can save yo money as you do not need to stack the inverters. magnum can stack four inverters which is 16,000 watts of steady state capacity, or 48,000 watts of surge power. you need to buy the MTR router to do this but its peanuts on a system this size.

but, here is the big thing.... any thing less than about 1000 amp hours of battery at 48 volts is not going to power the system very long...

so do a energy useage audit first and foremost. some things you can skimp on some you cannot. remember its easier to save energy then to make it... LED lights for instance. not useing the camper A/C and instead running a good split pack would save you tons of money in batteries. camper a/c units are the most inefficient that exist on this plant. (I have a camper... and I shit canned the coleman unit that was on it had to reseal the roof, but now I use a little tiny daikin unit that hangs off of the back bumper and it uses a full 75% less power for the same cooling and it can start on one magnum ms2000 2kw 12 volt inverter.

 

[chrisski]

I don’t know your power requirements, but a 50 amp RV could reach 50 kWh - 100 kWh per day with both ACs running non-stop 24 hours a day with electric hot water and electric fridge. On perfect weather when I have little use for electric, I am at 1.5 kWh. Huge difference.

In my signature block you’ll see an article that compares two areas with drastically different systems, “Same system different area, huge difference.” One is a solar friendly area by where I live in Arizona, and the other is a solar bleak area by where you live in the Pacific North West.

I also invite @Rednecktek who is doing what you want in your area. One of his threads are:

Putting Lipstick on a Pig - Fixing the camp! (Photo heavy)

So now that I've replaced my laptop and gotten some of my data over, I can finally post some pictures of what I've been doing out here in the woods. So when I bought this place the electrical system was seriously borked, and I didn't know any better. I knew enough to know that a piece of...

diysolarforum.com

IMO what you want is not doable without some serious conservation.

 

[Daddy Tanuki]

I don’t know your power requirements, but a 50 amp RV could reach 50 kWh - 100 kWh per day with both ACs running non-stop 24 hours a day with electric hot water and electric fridge. On perfect weather when I have little use for electric, I am at 1.5 kWh. Huge difference.

In my signature block you’ll see an article that compares two areas with drastically different systems, “Same system different area, huge difference.” One is a solar friendly area by where I live in Arizona, and the other is a solar bleak area by where you live in the Pacific North West.

I also invite @Rednecktek who is doing what you want in your area. One of his threads are:

Putting Lipstick on a Pig - Fixing the camp! (Photo heavy)

So now that I've replaced my laptop and gotten some of my data over, I can finally post some pictures of what I've been doing out here in the woods. So when I bought this place the electrical system was seriously borked, and I didn't know any better. I knew enough to know that a piece of...

diysolarforum.com

IMO what you want is not doable without some serious conservation.

yes as i stated, its easier to save then to make.

 

[DIYrich]

and he eventually wants to take the solar system back to his house.

Buy a UL Listed inverter like Sol-ark 15k. It may be overkill for the RV, but will work well in a grid connected house.

As ground mount, you can easily expand your system, so getting it right the first time is not critical if you have a backup generator.

UL9540 batteries will either be a 5kwh rack, or the larger 15kwh eg4 powerpro. The eg4 is 300#, so consider whether you can move it to the house. 15kwh is a good starting point, especially with AC. Again, design it right, and it can be easily expanded.

 

[chickencoops]

but even worse because solar production in the PNW in winter is almost nonexistent. So that means either switch to propane heat or go on the grid.

By almost nonexistent in winter, I mean you’ll get some solar production but no where even remotely close enough to heat an RV unless you put up 11 acres of panels. Maybe more. I didn’t do any math lol.

This is extremely alarming. Putting up 11 acres of panels doesn't seem realistic. lol The only grid power in the area is a tiny barn/shop with a 20 amp circuit that my grandpa personally put in 35 years ago and apparently that looks very sketchy and fire hazard! My dad doesn't want to invest anything into this land meaning he doesn't want to pay to run a new line coming from grandpa's house far away. Dad doesn't mind investing in the solar setup because he wants to take it all to his house later

these two come to mind of good vendors that back the products they sell

northern arizona wind and solar (NAWS)

Thank you for names!

but, here is the big thing.... any thing less than about 1000 amp hours of battery at 48 volts is not going to power the system very long...

so do a energy useage audit first and foremost. some things you can skimp on some you cannot. remember its easier to save energy then to make it... LED lights for instance. not useing the camper A/C and instead running a good split pack would save you tons of money in batteries. camper a/c units are the most inefficient that exist on this plant. (I have a camper... and I shit canned the coleman unit that was on it had to reseal the roof, but now I use a little tiny daikin unit that hangs off of the back bumper and it uses a full 75% less power for the same cooling and it can start on one magnum ms2000 2kw 12 volt inverter.

Nothing less than 1000 amp hours of battery at 48 volts. My goodness! This is turning into an epic adventure!
That's a priceless suggestion to run a split pack instead of RV AC!

I don’t know your power requirements, but a 50 amp RV could reach 50 kWh - 100 kWh per day with both ACs running non-stop 24 hours a day with electric hot water and electric fridge. On perfect weather when I have little use for electric, I am at 1.5 kWh. Huge difference.

In my signature block you’ll see an article that compares two areas with drastically different systems, “Same system different area, huge difference.” One is a solar friendly area by where I live in Arizona, and the other is a solar bleak area by where you live in the Pacific North West.

I also invite @Rednecktek who is doing what you want in your area. One of his threads are:

Putting Lipstick on a Pig - Fixing the camp! (Photo heavy)

So now that I've replaced my laptop and gotten some of my data over, I can finally post some pictures of what I've been doing out here in the woods. So when I bought this place the electrical system was seriously borked, and I didn't know any better. I knew enough to know that a piece of...

diysolarforum.com

IMO what you want is not doable without some serious conservation.

That is what I'm understanding from reading all your responses, that is a very serious conversation. Amazing info regarding "Same system, different area", Thank you so much for sharing your data and insights with the world!

Buy a UL Listed inverter like Sol-ark 15k. It may be overkill for the RV, but will work well in a grid connected house.

As ground mount, you can easily expand your system, so getting it right the first time is not critical if you have a backup generator.

UL9540 batteries will either be a 5kwh rack, or the larger 15kwh eg4 powerpro. The eg4 is 300#, so consider whether you can move it to the house. 15kwh is a good starting point, especially with AC. Again, design it right, and it can be easily expanded.

Sol-Ark seems fascinating. It looks like an all-in-one setup eliminating a lot of extra accessories one has to buy to make a setup work. It also looks price really quadruples with a Sol-ark setup but I do hear what you mean when you say to design it right!

 

[Brucey]

11 acres was a joke but you will need supplemental power from a generator during poor solar conditions.

 

[Mattb4]

...

Location: Pacific Northwest. Lots of cloudy and overcast days.

...

Unless the land is in the Banana Belt of the Pacific Northwest I would say Solar power as a main electrical source is simply not viable. No amount of storage (batteries) can overcome weeks of overcast gloomy days.

 

[DIYrich]

The only grid power in the area is a tiny barn/shop with a 20 amp circuit that my grandpa personally put in 35 years ago and apparently that looks very sketchy and fire hazard!

One 20 amp 120v circuit is 2.4kW. Let's say you run it at 15 amps continuous, that is 1.8kW, or 43kWh per day.

Put the RV near the Barn/shop, and run a 20 amp line from the Barn to the RV.
Build a basic system. Solar/Battery system.
Power a Chargeverter to recharge a 48v battery when there is not enough sun.
If 43kWh per day is not enough in the winter (and solar is not available), you can kick it up to 19 amps, or 55 kWh during those times. If you need more than that, you will need a generator.
If you are lucky to have 20 amp at 240v, then you should be golden.

Sol-Ark seems fascinating. It looks like an all-in-one setup eliminating a lot of extra accessories one has to buy to make a setup work. It also looks price really quadruples with a Sol-ark setup but I do hear what you mean when you say to design it right!

You could use a cheap inverter now, and get something better when it is moved to the house. With the sol-ark, you wouldn't need the Chargeverter.

If you have 240v from the Barn, then the Sol-Ark can handle everything automatically (you don't need the Chargeverter). The Sol-Ark can be limited to what it takes from the Grid. Set the SA to automatically charge from the Grid when batteries get below 20% (or whatever you set it for). If you have 120v from the Barn, you may be able to use an Autotransformer to provide 240v to the SA.

 

[chickencoops]

One 20 amp 120v circuit is 2.4kW. Let's say you run it at 15 amps continuous, that is 1.8kW, or 43kWh per day.

Put the RV near the Barn/shop, and run a 20 amp line from the Barn to the RV.
Build a basic system. Solar/Battery system.
Power a Chargeverter to recharge a 48v battery when there is not enough sun.
If 43kWh per day is not enough in the winter (and solar is not available), you can kick it up to 19 amps, or 55 kWh during those times. If you need more than that, you will need a generator.
If you are lucky to have 20 amp at 240v, then you should be golden.



You could use a cheap inverter now, and get something better when it is moved to the house. With the sol-ark, you wouldn't need the Chargeverter.

If you have 240v from the Barn, then the Sol-Ark can handle everything automatically (you don't need the Chargeverter). The Sol-Ark can be limited to what it takes from the Grid. Set the SA to automatically charge from the Grid when batteries get below 20% (or whatever you set it for). If you have 120v from the Barn, you may be able to use an Autotransformer to provide 240v to the SA.

It's 120v. There is some kinda logistic issue about parking the RV next to the Barn/shop and I'm told it's because there isn't a safe and easy access to get to it for a big RV but I guess anything is possible. It sounds like this 20amp circuit could literally be the difference between making it and not making it. So I will pass that along. I'm told my grandpa dug a trench himself to make this happen 30 or so years ago and it hasn't been load tested in over 15 years.

My dad has the same mindset as you when it comes to "Get it right the first time", so he probably opt for his long term inverter now. I was checking out the NAWS Arizona Solar "Daddy Tanuki" mentioned above, they have combo packs for Sol-Ark with Pytes v5 batteries

 

[MisterSandals]

The only grid power in the area is a tiny barn/shop with a 20 amp circuit that my grandpa personally put in 35 years ago

I've never heard of a utility line onto a property designed to handle only 20A. I would explore this more to see exactly what you have. Can you post a few pix of the main and meter?

 

[Rednecktek]

In my case I'm just trying to get a single 120v 3Kw system up and online. Most days I was up there, once I got the array and BMS all fixed and working, I actually ran at a net loss over the day, I.E. I started at 97% battery in the morning and had 93% at sundown, and I wasn't running the Aircon or anything high draw. That's just lights, coffee maker once a day, the TV, Starlink, my laptop for a couple hours, and the 12v battery charger to feed my 12v heaters. 2400w of panel wouldn't break even the time I was up there because I never got good sun while the system was online.

You're going to have to do a power audit, I'll throw my blurb in here next to get you heading in the right direction. It's going to be a HUGE array and battery setup to feed those dual Aircon units.

 

[Rednecktek]

Blurb time!

Well, I'll start the default answer to these questions and we can work from there. Here's you To-Do list:

1: Power audit! This will give you some important information on how big your inverter needs to be as well as how much battery capacity you'll need. There is a link in the FAQ section (I think, or someone here will post it shortly) so fill in the blanks and see what it comes up with. You'll probably need some sort of Kill-A-Watt to get accurate measurements. Are you going to be running a 12v system? 24v system? 48v system? What are the specs on your solar panels? VoC? Vmp? Being as this is a new build, throw together a wish list of what you want and estimate on the high side.

2: Where do you live? Speccing out a system for Scotland is a LOT different numbers than Arizona due to the amount of light you actually get. Someone here can post the link to the PVwatts.com or JCR Solar Uber-Sun-Hours calculator sites to help figure out how much you'll have to work with. That will be a box in the Power Audit form.

3: Parts list: You don't need a make & model list, just a parts list to start from for reference. You'll need an inverter, a MPPT charge controller, fuses, shunt, buck converter, batteries, wire, etc. Once you have a basic list it can be fine tuned to make & models after that. If you're looking at the All-In-Ones check for correct voltage outputs (120v or 240v Split Phase for North America, 220v Single Phase for European type areas) and make sure it has enough capacity for a little bit of growth and fudge factor.

4: Budget!: Steak is great but doesn't mean anything if your wallet says hamburger. Figure out what you're able to spend now vs what you'll have to cheap out on now and upgrade later.

5: Tape measure! Figure out where you're going to stick all the stuff you'll need. A dozen 3000AH batteries sounds great until you're sleeping on the floor because there's no room left for a bed. Is there a compartment that can house all this stuff? Will the server rack batteries fit? Are you going to have to make space? Physics can be pretty unforgiving.

6: Pencil out what you think you need and throw it at us so we can tell you what you've missed (because we ALL miss stuff the first go-round ) and help figure out which parts and pieces you're going to want to get.

Well that's the thing about solar systems, there is no 1-Size-Fits-All answer. Your system will need to be designed to fit YOUR needs. When you design and built the system, it's not going to be the perfect system for me, or Will or 12vInstall or anyone else, but it Will be the right system for You and that's the goal.

Don't panic on the Power Audit, you'll actually be doing that a few times. When you do the first pass put in ALL the Things that you might want. AirCon? Sure. Jacuzzi? Why not. MargaritaMaster-9000? Go for it.

The second pass will be the "I Absolutely Need This To Survive" list that isn't going to have much on there.

The third pass will be the "This is what is realistic" audit that you'll use to design the rest of the system.

The Power Audit is going to tell you 3 primary things: 1: How big does your inverter need to be to power your loads? 2: How much battery bank do you need to last $N number of days with krappy weather? and 3: How much solar panel will I need to install to refill those batteries in a 4 hour day (the average usable sun hours rule-of-thumb).

Once you know what you Want and what you Need and what your budget can Afford there will be somewhere in that Venn diagram where those three things meet.

After that, THEN you can start looking at parts.

Yes, it's a long drawn out process, but it's worth it in the end. Not every house has the exact same floorplan, not every vehicle is the same make & model, and not every solar system is designed the same.

 

[sunshine_eggo]

+1 to others and @Rednecktek

Link #1 in my signature gets you to the relevant planning resources.

Also wanted to discourage the choice of Quattro for the stated reason. The two inputs are NOT solar + AC. They are two separate AC inputs typically grid and generator. Only one can be active at a time. For solar, you need a separate MPPT.

The only reasons to choose a Quattro over a Multiplus/Multiplus-II:

1. You have a compelling need for two AC inputs that can't be met with an external ATS (auto transfer switch - most 50A RVs with generators have this).
2. You can't get the MP/MP-II in the desired voltage/power needed.

We're off-grid on 40 acres with a system in a shipping container powering two 5th wheels.

I have 2X Quattro 48/5000 because there wasn't a 48V/5000W Multiplus available at the time. If I had to do it all over, I would choose 2X Multiplus-II 48/5000 today. They are UL pending and have been optimized for even lower power consumption.

 

[DIYrich]

It's 120v. There is some kinda logistic issue about parking the RV next to the Barn/shop and I'm told it's because there isn't a safe and easy access to get to it for a big RV but I guess anything is possible. It sounds like this 20amp circuit could literally be the difference between making it and not making it. So I will pass that along. I'm told my grandpa dug a trench himself to make this happen 30 or so years ago and it hasn't been load tested in over 15 years.

My dad has the same mindset as you when it comes to "Get it right the first time", so he probably opt for his long term inverter now. I was checking out the NAWS Arizona Solar "Daddy Tanuki" mentioned above, they have combo packs for Sol-Ark with Pytes v5 batteries

I assume it is 3 wire 120v: Line, Neutral, Ground. If so, you could swap the Neutral for Line 2 and get 240v with no neutral. That would double the power to the CV with the same amount of amps. The problem with sending 240v to the Grid input of the SA/EG4 is that I think they are expecting a Neutral wire (4 wire including ground). CV doesn't connect the Neutral Wire, so 3 wire works.