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02-04-2025, 12:05 PM
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#1
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Junior Member
Join Date: Sep 2024
Posts: 6
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Solar system requirements and recommendations
Hello all,
I am fairly new to the forum and have not yet completed my me member check in, but I am hoping some of you may be able to assist in providing some insight to the above mentioned topic.
I have recently obtained a 1983 Holiday Rambler Imperial 23 ft RV. I've been playing around with it and doing some remodeling. So far it's coming out great.
I currently have a 30 amp system and the converter. Obviously the 12 volt as well. So I plan to be traveling the country and I will be working from the road. I am wanting to know if I need to increase my amperage, first of all. Also what type of solar system will be required for me to run my normal appliances along with a desktop computer with two monitors, of course my modem as well? How many watts would you guys recommend, I was looking at purchasing lithium batteries for it as well. Now these lithium batteries will replace my normal lead-based 12 volts correct? I know I'll need an inverter and a control panel as well. But the last two have me a bit confused. Anyone that could help will be so greatly appreciated!
Thank you all for your time in advance and I look forward to hearing from any of you at your earliest convenience! Have a great day!
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02-04-2025, 12:13 PM
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#2
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Senior Member
Join Date: Nov 2018
Location: Fulda, MN
Posts: 1,849
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Are you planning to do all this with no shore power? If so, you need to figure out how many watts you are going to be using at one time and how many hours. Then go from there. It sounds like you will be using a lot of power. Those electronics will take a lot of power if using them all at the same time.
__________________
2000 Winnebago Adventurer 32v, P32 Workhorse
2005 Winnebago Adventurer 38J W24 Workhorse 8.1l, 5 Speed Allison MH2000
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02-04-2025, 12:46 PM
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#3
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Senior Member
Join Date: Apr 2024
Location: WI Driftlesser
Posts: 2,518
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Are you planning the install yourself? I assume so, because not many people would put a $10-20,000 solar Li system in an '83.
The big question is HOW LONG do you want to run the appliances, and how long do you want to go without running the generator, and how much are you willing to pay to do that? The 30A shore power system will run nearly 4KW of power. Converting to 50A would get you 12KW of power, when plugged into a grid that will support that. A 2 or 3KW inverter will run a microwave, hair dryer, etc. one at a time, or two on 3KW. The size of the battery bank will determine how long it will run, the size of the solar will determine how fast the batteries recharge so you can do it again.
If you go with 1,000w or more solar, it starts to make sense to go with a 48V DC system for the Li, and put everything 12V on the chassis batteries. For instance a 48V 3kw all in one inverter, charge controller, shore charger and 5kwh battery are about $2k in parts. That's one battery, so much simpler and more reliable than 4 12V in parallel.
__________________
"Bringing third world electrical work to first world luxury." RV makers of Murica!
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02-04-2025, 01:00 PM
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#4
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Senior Member
Excel Owners Club Ford Super Duty Owner
Join Date: Aug 2014
Location: Santa Fe, NM
Posts: 7,213
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Welcome to the forum. You can learn a great deal here from lots of experienced people.
So many unknowns here to make solid recommendations.
1. Will you staying in RV parks with full hooks ups?
2. How often will you be staying off-grid?
3. How much spare do you have for batteries, What shap?
4. How much space and shape of roof space do you have for solar panels?
5. Would you be up for ground based portable solar panels fo rpart of the solution?
6. What is you knowledge and skill level with electrical systems?
7. What kind of budget do you have for this project?
8. Need total power draw of all computer related equipment and number of hours per day of usage?
9. What other electrical devices would you be using outside beside lights?
This is just a starting list of questions?
I'm in the design phase of a major upgrade to a new travel trailer arriving in about two months. Upgrades from 30 amp main service to 50 amps and to lithium involves many changes.
__________________
Fred & Denise (RVM157) New Mexico
2007 Excel Classic 30RSO & soon ORV 19MKS
2007 RAM 3500 Diesel 6Spd Auto, SWD, 4x4, CC&LB
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02-04-2025, 02:18 PM
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#5
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Member
Join Date: Apr 2018
Posts: 86
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Im thinking you want to set up a inverter/charger. You will need to figure out how many watts AC max will be running. Also need to calculate AH used in 24 hours. Start with AH your unit has and how long last. If you are on shore power most of the time, lithium AH are not as big a deal. Solar will need separate charge controller. Most the people on this forum are very knowledgeable on this subject and will be fun to follow along and learn.
__________________
St. Louis Missouri
Longing for retirement
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02-04-2025, 02:41 PM
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#6
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Junior Member
Join Date: Sep 2024
Posts: 6
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Solar system requirements and recommendations
This is all great information.
David...I plan to boondock as much as possible. I've had so much fun with this in the past. I was out for a little over 2.5 years last time. Although I'll be full time, my idea of traveling doesn't include sitting in an RV park unless I have extremely pressing water needs, have Internet issues, or the RV needs work. As far as the monetary investment on such an old RV, I don't disagree with you. But I've had so much fun customizing it and I've grown quite attached, so I plan on keeping it for awhile, so what I'll profit isn't my primary concern. Whatever I put into it will pay for itself pretty quick. The biggest downfall will the be fuel costs. 4 barrel carb 454 and 7.5 will be a guzzler for sure, but that will wash out if I'm able to clip shote power costs (for the most part), cut down on generator fuel usage, and minimal RV park costs.
Ben and rarebear,...As far as my appliances go, I have a three-way refrigerator, and am going to replace my microwave for the same. My intention is to use the solar panels as much as possible with propane as backup when necessary. My water heater is propane with an electronic igniter. My water pump will be used on average for one person most of the time but at times I'd like to cover at least six people. That wouldn't be all the time so it would just take a little organization between us I suppose. I am going to attempt to use my generator as little as possible. But it's fully functional and will be used when needed. I do currently run a desktop but may consider transitioning to my laptop with a couple of extra monitors for work, which would be anywhere from 6 to 8 hours 5 days a week. I believe my dometic AC is 1200 w. Depending on my location of course will determine how long I run that per day.
So this is what you guys are for...lol...
I found a really great deal on 600 w panels with control panel, and inverter that handles up to 3000 w, 12v 100ah batteries. Am I close to on the right track? I do know a bit about electricity, but am not a pro for sure. Do you know how many of the 600 watt panels I should get? I found that they produce anywhere from two to five kilowatt hours per day if I'm not mistaken correct? I was thinking three just to cover myself. I guess I also need to factor in my internet. I'm thinking starlink Roam, but I've seen some less expensive and possibly more reliable options that I'm looking into as well. My furnace is propane with an electronic igniter. And there's always the handy Mr heaters that run on an external tank in a pinch. And I can actually drive this thing on LP as well. This dual fuel system is something I have not figured out yet, but it's on the list. LOL Obviously everything won't be running at the same time but I'm still a little confused on how to firmly calculate my usage per day. Total wattage divided by 3 if I'm not mistaken? My goal is to over estimate rather than the opposite.
David, I also find your recommendation of the inclusive inverter, controller, and shore charger compelling. I want aware that was a possibility. If live to gain a better understanding of connecting to the Chassis battery, but I don't mind 2 Li.
I can post some some photos of the items I've found and maybe you guys could tell me if I'm looking in the right direction. I'm a diy girl, and I learn as I go. If I didn't know, I'm one that bound and determined to figure out! More times than not, I find i succeed. So that's my story this far!
Thank you all so much! And rarebear, I'm not sure if I've answered all of your questions, but I hope I provided enough info to give you all and idea of my ultimate goal.
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02-04-2025, 03:44 PM
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#7
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Senior Member
Join Date: Nov 2018
Location: Fulda, MN
Posts: 1,849
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Those Mr Heater are not a good choice for inside an RV. They put out CO2 and a lot of moisture. If you don't wake up dead, there will for sure be a lot of moisture inside your rv.
__________________
2000 Winnebago Adventurer 32v, P32 Workhorse
2005 Winnebago Adventurer 38J W24 Workhorse 8.1l, 5 Speed Allison MH2000
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02-04-2025, 06:14 PM
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#8
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Senior Member
Excel Owners Club Ford Super Duty Owner
Join Date: Aug 2014
Location: Santa Fe, NM
Posts: 7,213
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OK. I believe you can do this with some assistance from the forums. You've got what it takes.
I may break my responses up so to avoid writing a novel. Sorry about about my typing this morning, guess I was not very awake at that time.
Using used solar panels is frequently a good way to go. 600 watt panels are most likely used commercial grades panels. I prefer those over common RV panels. They frequently are better in low light/low solar angle conditions.
600 watt panels are likely about 49 x 90". They can be a challenge placing on your roof. On my 5th wheeler I used that size panel and just raised them enough to clear the various tank vents. Being a DIY with a nice shop I just made my own panel mounting brackets. You can find tall brackets on the market if you look enough.
Those panels are most likely about 40 -50 volts each. So no need to wire them in series. Series is mostly mostly done to increase voltage. The other option, best with those panels with be wired in parallel. That increases the amperage but maintains the same voltage. So you need larger gauge down haul wires to the solar controller. At that voltage I would also fuse each panel on the roof for safety.
You are going to hear plenty about volts, amperage and watts. Get comfortable with terms if you are not already. They are all related as follows:
watts (W) = Amperage (amps) x Voltage (V)
If you know two you can calculate the third value.
In sizing wires you need to know at least the amperage and round trip distance for DC current. Not just distance from say solar controller to the solar panel. But the round trip distance. There are many tables on the web for wire amperage sizing. Smaller wire gauge numbers means bigger diameter wire. You will see in this operation sizes such #8 to #0 and 2/0 or 4/0. 4/0 is like 0000 size wire, about one inch round.
You also need to pay attention to voltage loss (drop) across any wire. Those wire tables may indicate sizes for a given amperage and distance depending on desired voltage drop. Doing this stuff you want to keep voltage loss under 3%. Every foot of wire and connection adds some voltage loss. Voltage loss results in wasted energy and thus heat. So wire temperature rating is important. I like wire rated for about 105C.
If you already understand all of this techy stuff, say so. We'll scale the discussion differently.
Here is a very basic solar, inverter diagram for a system.
The solar controller(s) should be as close to your battery bank as possible. Shorter distance allows smaller (cheaper) wire. Many solar controllers are named like MPPT 100/50 or MPPT 150/75. The first number is typically the max down haul voltage. The second (50,75) is the output amps from the controller to be the battery bank. There should be breakers on both sides of the controller, input and output for safety and ease of doing future service on the controller.
Generally I like Victron Engery branded products. There are other fine products as well. I also prefer systems designed with devices (controller, inverter, etc) that are discrete devices opposed to all-in one solutions. Both will work. But if you need to upgrade one item or replace it, it's cheaper with discrete devices and easier to trouble shoot. Things will go south sometimes.
In my book about all things electrical safety is first.
That's plenty on that subject today.
__________________
Fred & Denise (RVM157) New Mexico
2007 Excel Classic 30RSO & soon ORV 19MKS
2007 RAM 3500 Diesel 6Spd Auto, SWD, 4x4, CC&LB
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02-04-2025, 06:28 PM
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#9
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Senior Member
Excel Owners Club Ford Super Duty Owner
Join Date: Aug 2014
Location: Santa Fe, NM
Posts: 7,213
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One more topic for now.
Batteries:
I assume you already have an understanding between various lead based batteries vs lithium solutions.
For what you want to do, it's lithium all the way. Much greater energy density for less weight and lower cost of ownership over time. I have two RVs right now. One is used for off grid travels and the other is more for long term parked use. I use lead/acid in the parked RV and lithium in the tripper RV. Different needs, different solutions.
what others have said you need to get a grip on your power needs. This is frequently called an energy audit. Various ways to get at that value.
One you use the name plate wattage information on each device. But this is the maximum value, not the real amount used. Either way create a table (spreadsheet) of each device (computer, monitor, lights, hair dryer, water pump, AC unit, etc) then add wattage and estimated hours per day of use. That gives you the daily watts used per device, Total those and you get total daily wattage needed.
Two, install a battery monitor. For example a Victron Smart Shunt with a meter. There are other brands and models. This gives you total power running though you battery bank. Now turn off every breaker/fuse except one and then turn on one thing at time. That should give you the power used by that device. That will likely be in amps. Do same as above for a total. Side note, last time I did this I would get different amp readings for three different lights all using same LED bulbs, bought at the same time.
Get a total daily amp hours used figure. This will vary if you run the AC or furnace, etc. Work out those details.
Now you have some real numbers to use in designing and building your system. Without it, you will be guessing doing what someone else has done. Which will be different from your won needs.
I love solar systems. But how much solar gain you'll get per day varies a lots. Depending on sun angle, clouds, trees, other shading, temperature and quality of solar panels. So if you're in the sunny southwest or the not sunny Pacific Northwest you'll get very different results. Commercial grade panels will do better in all conditions. I designed one RV system to provide 100% of my 12 volt power north of the Aritic Circle in the summer using commercial panels. It worked great. Fully charged by 10 am every day, except when I was under shade with snow on the roof. It can be done.
As a starting point a design with at least 30% more solar panel capacity than my usage numbers indicate. This allows for most of the solar losses.
As for the battery bank vs solar system. A good rule of thump is double the battery bank A/Hr (amp hours) total for solar wattage. For example if my daily amp usage value is say 500 AHrs then I want at least 1000 watts of solar.
In the design I'm working right now for a new RV we're getting, I'll have about 2-3 times solar wattage of my battery bank AHrs. In our typical travels we move locations much more than staying put somewhere. So I have a circuit from the engine's alternator to recharge the batteries, as well as the generator or shore power.
Next will you be spending time in places with temperatures below 32F? Will your lithium batteries be inside heated space or in an outside compartment? If outside and temps are below 32F you can't recharge most lithium batteries. Many companies do sell internally heated batteries. In my testing Battle Born heated batteries will stay between 35 and 45F even in sub zero weather. Fine to stay charged. I'm sure other brands will do similar. But decide if you need heated batteries or not.
In the past most lithium batteries were somewhere about 100Ahr + ratings. Today many lithium battery companies are selling larger models around 300-500 Ahrs. Some are heated some not. A pair of those can nicely power your RV. As for brands that's another series of lively threads in these forums. Or build a battery bank from more 100AHr batteries. Some lithium batteries are more or less expensive some are much better some are not and some are in the sweet middle of the matrix. You have to figure out what you want.
Enough said and it's diner time.
__________________
Fred & Denise (RVM157) New Mexico
2007 Excel Classic 30RSO & soon ORV 19MKS
2007 RAM 3500 Diesel 6Spd Auto, SWD, 4x4, CC&LB
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02-04-2025, 07:03 PM
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#10
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Senior Member
Join Date: Apr 2024
Location: WI Driftlesser
Posts: 2,518
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Quote:
Originally Posted by Red13
I have a three-way refrigerator, and am going to replace my microwave for the same.
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Not sure what you mean with the microwave? I thought that had to be 120V? Sounds like you will have an inverter, so a low wattage microwave (600-800w) is easy to find, and just a little slower, but you should be able to run the current microwave fine on any inverter we're talking about. An induction "burner" is another nice appliance. Forget about using the stock rooftop air for more than a very short time. Get a multi speed window, or heat pump unit if you're planning to run one off grid. There are 48V inverter heat pumps if you're that serious about off grid air conditioning. Forget about running a propane fridge on solar also, get a residential fridge, or convert a chest freezer to a fridge, or other options depending on how determined you are.
__________________
"Bringing third world electrical work to first world luxury." RV makers of Murica!
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02-04-2025, 09:50 PM
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#11
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Senior Member
Excel Owners Club Ford Super Duty Owner
Join Date: Aug 2014
Location: Santa Fe, NM
Posts: 7,213
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From experiences we all have own opinions.
It is my opinion that when trying to stay off grid you want as many options as possible to operate your most important equipment. You are talking about a 23ft RV. That allows far less roof space than larger RV, thus a smaller possible solar footprint. That will limit how much recharge capacity you will have. I had a 24ft Class C and understand those limitations.
What I'm getting at is that 2 and 3 way appliances are good. You have backup options if something is not working. I have a 3-way refrigerator right now in our current Class C and the option to run on AC, 12 volt or propane has been great at times. I know people have bad comments about keeping food cold enough in absorption refrigerators. I enjoy hard ice cream and crackling ice from ours. The freezer is frequently below 0F. But I have two sets of three fans each in the refrigerator's chimney to keep air moving, top and bottom. That makes a major difference.
IMO- keep your options open.
__________________
Fred & Denise (RVM157) New Mexico
2007 Excel Classic 30RSO & soon ORV 19MKS
2007 RAM 3500 Diesel 6Spd Auto, SWD, 4x4, CC&LB
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02-05-2025, 08:21 AM
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#12
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Senior Member
Winnebago Owners Club Workhorse Chassis Owner
Join Date: Nov 2018
Posts: 2,998
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Some good baseline information here to consider. Will offer the following: "I installed too much solar!" said no one, ever. For what you're considering, there's no practical reason to not cover your entire roof with panels. They're the cheapest components of the system, just max it out. The consideration then becomes how much battery you want, limited by your storage space and budget. That'll be your cost driver. Then lastly, clouds. They render the most diligently and accurately crafted solar system moot. You're going to need a generator, and I would offer not the 3600RPM buzz boxes that are typically preinstalled. What I've found works well is a basic, small inverter genset that you can place far away from the RV that you let putter a few hours a day if needed. It's noble and intellectually satisfying to create and successfully be 100% off grid with a solar system of your own making, but there's only so many contingencies you can accommodate. Enter the inverter genset, and life is simple again.
Some sage advice from a grizzled off-grid solar guy I know that did this long before lithium and processor based controllers - a watt not used is two watts you don't need to generate and store. Thoughtful selection of your equipment, and prudent economizing what you do and when use makes a huge difference in the generation and storage that you need. Use high draw devices singly and not at the same time. Use as much of your panel generation as you can, and minimize what you draw off batteries at night. Things you may not give a second thought to while at home, but when you have a finite power source they make a big difference.
Mark B.
Albuquerque, NM
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02-10-2025, 04:25 PM
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#13
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Junior Member
Join Date: Jan 2025
Posts: 2
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Hello,
I myself recently installed a large solar system in a 1989 20 foot damon escaper. I have 1200 watts of solar on the roof with 960 amp hours of LiPO4 batteries at 12 volts.
As others have said I would go with a 48 battery system if you're trying to use primarily solar energy however I would use a converter and step the 48 Volts down to 12 volts for systems that need it versus the chassis battery, but that's a preference.
As Mark said, no one ever said too much solar, it's just a matter of where to put it. Depending on the space you have you can use solar panels that fold put on the ground instead of your roof, or if you're feeling really froggy try your hand at a solar awning. With panels as well you have so many options nowadays depending on your budget. I used 4 Renogy 320 watt home panels for my build, but you have flexible solar panels that weigh 7 pounds, the ground solar panels I mentioned dont weigh much more. I have some ideas after doing my system but I'll keep my bad ideas mine for now.
Also, as mentioned, clouds, they definitely mess up your energy plans so the generator or a chassis alternator tie in to charge the house batteries as the engine runs is needed if you're off grid a lot.
Hope this helps you weigh some more options for your system, I'm no electrical pro either.
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