Many new full-time RVers hit the road without solar power systems on their rig for two big reasons:
- Many new full-timers don’t know if they will enjoy the lifestyle enough to commit to investing more money into it.
- Others don’t have experience dry camping and aren’t even sure if they’ll like it.
Waiting to invest in RV solar power seems like a smart move if you fall into either of those two categories. But if you’re like my husband and I, and you already know you enjoy getting off the beaten path and deep into the woods or far into the desert, paying for a good RV solar power system before you hit the road is a better idea.
Still undecided? Here’s my list of RV Solar Power Pros and Cons, as requested by one RV Life blog reader. Keep in mind I’m not a RV solar expert, but I have absorbed a ton of information by observing how my husband has dealt with our systems over the last eight years as full-time RVers.
Top 3 RV Solar Power Cons
RV solar power can be expensive.
Well, let me back up; a cheap system that costs, say less than $1000, is definitely helpful but it’s probably not going to power everything you need to be comfortable. Our first system (about $1800 back in 2008) wasn’t large enough for us, even after we made a few upgrades. When it came time for a new-to-us RV, we made sure to invest enough in RV solar to power all of the items we feel make our lives comfortable and productive. Keep in mind, we don’t have television but we do have a mobile satellite Internet system, which is a big energy hog. Everyone has different power needs.
I was especially surprised that the cost of our robust system (around $3700) was about the same as it would have been eight years ago. Unlike domestic home solar power systems, RV solar pricing hasn’t decreased as much as I assumed.
In case you’re wondering, the main components of our new RV solar power system include:
- Renogy 100w Solar Panels (QTY: 5 = 500 watts total)
- Solar Boost SB3000 MPPT Charge Controller
- Blue Sky IPN Remote Display
- Xantrex ProWatt 2000 Pure Sine Wave Inverter
- Trojan T105-Plus 6v Batteries (QTY: 4)
- Automatic Transfer Relay Switch
RV solar power can be complicated.
Again, I preface this by saying that I have no tolerance for learning about electricity or any of the things you must do to plan for the right RV solar system, like performing an energy audit. You can pay someone to do it for you, or figure it out like my husband did. Once the system is installed, it’s pretty self-managing but occasional glitches do happen. You can read about my husbands RV solar observations, here.
RV Solar Requires Time to Recoup the Investment.
One of the reasons RV solar is awesome is that it can greatly reduce your camping fees, if not eliminate them altogether. Each season we head out to the Southwest for several months and we enjoy free camping on public lands while living off grid. Both times we decided to buy RV solar, it paid for itself in just a few months because we practically eliminated RV camping fees. However, that’s just us – we love dry camping and rarely stay in RV parks. Therefore, depending on the complexity of your RV solar system and how often you dry camp without hookups, you’ll need a hearty dose of patience while you wait to recoup the investment.
If you have a RV solar electric system, I’m really curious how my own list of RV solar cons compares with yours. Do my theories match up? Let me know below.
Now that we have a few of the negative cons of RV solar behind us, next week I will share my top three reasons why I know RV solar electric systems rock!
Rene Agredano and her husband, Jim Nelson, became full-time RVers in 2007 and have been touring the country ever since. In her blog, Rene chronicles the ins and outs of the full-timing life and brings readers along to meet the fascinating people and amazing places they visit on the road. Her road trip adventures are chronicled in her blog at LiveWorkDream.com.
Thanks for the info. So does solar power replace a generator? I think we would be dry camping half the time. The other half, my husband would do some workamping jobs to secure a free site and hookups.
Rene Agredano - The Full Timing Nomad says
Great question, Carrie! No it doesn’t replace it since cloudy days do happen occasionally and you’ll need some extra juice to top off your batteries. We carry a Honda super-quiet genny in the truck and use it occasionally, usually if we’re working late into the night but that’s rare. With a good system, the genny is just back-up.
Patty & Doug says
Actually for us solar has replaced our generator. It really depends on individual needs.
Hi, How many 100W panels like yours do you think it would take to run my refrigerator 24/7, a TV about 5-8 hrs a day, laptop a couple hours a day, and maybe a small CD/stereo when TV isn;t on and fans.
Then if I add AC that would probably be an additional what, 100 wt panel?
Rene Agredano - The Full Timing Nomad says
JB, as I mentioned, the best way to find out your power consumption needs is to do an energy audit with your own appliances. Since everyone’s are different there’s no way I could guess. A solar expert probably could but not me. Sorry, wish I could help.
You ask about the number of 100 watt panels you need for a small load. There is no easy answer. And realize that a “100 watt:’ panel is 100 watts only when at right angles to the sun, and might make 50-60% of that when laid flat on the roof of a RV. And there had better not be anything shading the panel! One dirty secret that no salesman will tell you is that 100% of the panel needs to be in full sun – a shadow from a air conditioner that covers 10% of the panel will zero out that panels generation.
To answer your question you have to know how much energy YOUR lifestyle uses. YOU need to do an energy usage log, then convert those numbers into battery size, then from there into battery charger size, then from there into solar panels needed.
Someone that lives in the New Mexico desert with an 8 hour summertime solar day for months at a time will need fewer panels than someone who lives in Montana in the wintertime with a week of 4 hour solar days followed by a week of cloudy days.
Air conditioning is the biggest energy hog. Refrigeration (i.e. fridge/freezer) is the second largest, simply because they are on and using energy a big percentage of the time. A microwave oven is the third, biggest energy hog but since it is drawing power for short periods of time that lowers it to #3 in total energy usage per day.
The biggest single thing you can do to reduce your energy usage is to improve the insulation of your RV and to close off any outside air leaks..
Example #1: – I have an mid-1980s Fleetwood class A. I had a built-in vacuum that exhausted outside. I did not realize it, but that was effectively a knee-high 2-and-a-half inch diameter hole from the bedroom wall to the outside bottom of the coach. Once I plugged that hole (with an old sock) my bedroom warmed up tremendously in the winter and cooled down in the summer.
Example #2) a friend had to replace the outer skin on his older RV and when he opened up the walls he found almost zero insulation. He installed new insulation and lots of it. He also replaced the old windows with new double pane windows. His RV had dual roof-mount air conditioners and dual propane furnaces – one of each for the bedroom and the other for the front. After the insulation refit he was using only the front unit and for about half the hours per day. His solar system is less than half of what he would have needed prior to the insulation retrofit..
Note that in many cases you can use your the energy you do use more efficiently. Many pieces of electronic equipment use AC powered, “wall warts” or battery chargers but frequently you can get 12 volt versions. I use a charger designed for a automobile cigarette lighter for my cellphone. My internet DSL modem and Linksys router both use a 12v DC wall wart. I have both connected to the house battery directly. I also have an automobile cigarette lighter charger for my electric razor. My CPAP (overnight breathing machine) came with a 120vAC-to-24vDC converter – it’s a 24 volt device internally. I made a 12 volt to 24 volt converter box using an industrial power converter module I purchased on ebay for $34. My RV TV was designed to run on 120v AC but internally runs on 40v DC. I modified another industrial converter module that originally made 48 volts from 12 volts and it now powers .the TV from 12 volts.
All of the above means that I no longer need to run my RV inverter at night… and the no-load idle power of the inverter was about 3-4 amps at 12 volts…. 36-48 amp-hours of battery were wasted every hour doing absolutely nothing.
A laptop uses DC power from an internal battery – and most are laptops are 17 to 19 volts internally. They come with a laptop charger that runs on 120v AC (home wall outlet power), but for an RV to have 120v AC means that the RV has to have an inverter to make that AC power from the 12 volt battery… and a laptop charger that uses 1 amp of 120 volts AC is going to use at least 10 amps at 12 volts (assuming perfect conversion efficiency and perfect conversion does not exist… there is always some conversion loss) .
So what do I do?
When I bought my last laptop I made a point of picking a model that had a 12 volt charger available – both Dell and Panasonic have them for customers that work out of their cars – insurance agents, construction sites, etc. Picking the right laptop is one more way that I can avoid running the RV inverter.
The energy usage of a TV set varies – the older glass picture tube units were big energy users. The plasma flat screens were less, but the newest flat screens are energy misers by comparison.
Again, the correct answer to your question is for YOU to do an energy audit – start by keeping an energy diary for at least a week, preferably 2 weeks, and ideally for a month..
Start with waking up: do you turn on the furnace for a half hour to take the chill off? (and note that the RV is chilly because you don’t have enough insulation to keep the heat in) Log it.
How long do you run the microwave for your morning coffee? Log it.
How long do you run the toaster for your breakfast english muffin? Log it.
How long do you run the air conditioner or fans? Log it.
How long do you run the TV? Log it.
How long do you run the Nintendo and TV? Log both.
And do the log as the number of watts (from the appliance nameplate) and the time in tenths of an hour. If the nameplate does not have a watts number then multiply the volts times the amps – for example, 120 volts times 1.5 amps is 180 watts.
Then multiply the watts by the time to come up with watt-hours.
Example 1: 180 watts for 1 minute (i.e. for 1/60 of an hour) uses 3 watt-hours of power.
Example 2: a microwave that is nameplated as 1200 watts for 8 minutes is 160 watt-hours.
(method of calculation is 8/60 = 0.1333. 1200 times 0.1333 = 160)
Then when you go through your months worth of log the highest total watts used at one time plus 25% will be your inverter size you need. The 25% covers conversion loss and gives you a bit of “headroom” on your system..
The total watt-hours for the day, week or month will determine the battery capacity you
need – and (the longer that you make the log the more accurate and useful your energy audit will be)
Then divide the total month of watt hours by 120v and that determines the amp-hours of energy you used.
Add 25% and write that number down.
That’s the number of amp-hours you will need to pump into your battery every 24 hours. Then realize that a solar panel has to be at right angles to sun for maximum energy generation, and one that’s flat on the roof of the RV is making maybe 60% of that, and usually less.. And realize that a “day” can be as short as 5-6 hours of sunlight depending where you live and even less if you have a series of cloudy days.
Lets say that your log shows 3200 amp-hours per month (and that’s a low number).
Figure a 30 day month.
That’s 106.6 amp hours per 24 hour period, and that divided by 5 solar hours is 21.3 amps every daylight hour. Add 25% to cover losses and a bit of headroom gives about 27. amps.
At 12 volts that’s 324 watts. You’d need four “100 watt” panels at right angles to the sun for a system that has almost zero excess power. If the panels are flat to the roof of the RV you had better have five. And it still won’t survive a cloudy week (you had better have a good Honda generator).
The secret to a good working solar system is to minimize the voltage drops and to maximize the amps into the batteries, which means lots of thick copper wire. ,
Look up the RV solar writeup by “handybob”. That guy knows his stuff.
For what it’s worth, I have 4 panels on tilt-able mounts and am budgeting for two more.
I don’t run the microwave, TV or run the air conditioner unless I’m plugged into shore power.
I have 8 100 watt solar panels and 20 12v batteries on my farm and I can constantly pump water day and night to irrigate.
….but i wouldn’t put a solar system on my motorhome.
They are way too expensive for what they can deliver.
I look for a shade tree when I park so they won’t work well. When driving the alternator will charge my batteries.
They also add weight and make holes im my roof to mount.
A small $100 generator will charge my batteries in a couple hours (at most) on 50 cents worth of gas.
Thomas Seim says
It is highly unlikely that an RV solar power system will pay for itself. As already noted, you will need a backup generator anyhow, so no savings there. I installed a home solar system and carefully analyzed the payback period. Without the federal solar tax credit (which you may be able to get for your RV http://www.wholesalesolar.com/solar-information/federal-tax-credit) and the local production incentives (which you won’t be able to get) the payback period exceeded the expected lifetime of the system. In other words it is not economical. The payback period with just the federal tax credit is very marginal.
The economics for an RV are much worse than a home, where the system is used continuously year around. This is not the case for an RV, which is mostly used part time (unless you are the exceptional full timer).
Performing an energy audit is a difficult task at best. Just measuring instantaneous power draw is highly misleading because energy is power used OVER TIME. This requires monitoring power at short intervals over an entire day. One way to do it easily is to attach an energy meter to your battery system, such as the GT Power watt meter (https://www.amazon.com/gp/product/B00ORGDQOK/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1). You can avoid high current battery connections by inserting this inline with your external battery charger; use your RV for a full day just on battery power (starting with fully charged batteries), then monitor how much energy is required to recharge the batteries.
I think solar systems make sense for those RVers that want to do extended boondocking and wish to be as self-sufficient as possible.
Rene Agredano - The Full Timing Nomad says
Thanks for sharing your perspective Thomas. Since the article was written for my Full-time RVing blog, it was geared toward those who are considering the lifestyle. You summed things up quite well when you said “I think solar systems make sense for those RVers that want to do extended boondocking and wish to be as self-sufficient as possible.” This is exactly the way my husband and I like it. Our system has been incredibly economical for us: we’ve saved thousands in camping fees over the last nine years of full-timing, and as a bonus, we’ve only needed to buy one generator so far, the amazing Honda EU super quiet model. It cost about $800 at the time and is still going strong. Everyone’s camping preferences are different, but we can’t imagine full-timing without solar.
You can actually do it without a back up generator. You simply need the correct solar system and WIRING. The WIRING is the biggest thing, if you can’t get the AMPs to the batteries you are simply wasting time putting up solar panels.
You will never be able to run an AC unit but everything else can be run. With a proper adjustable charge controller set at the correct settings, your battery bank will be full in less than a day. Even on cloudy days I watch my charger charge away.
I have 1 Kyocera 140 watt panel with a Morningstar Tristar 45 amp charge controller 2 Trojan T-105’s, heavy wire, and my batteries stay charged. I will be adding another panel, 2 more batteries, and an invertor later to run all the regular household stuff.
I live full time in a 37′ fifth wheel on ten acres and have for a year now.
This guy boondocks full time and doesn’t ever run a Genset.
Rob b. says
I have six 145 watt panels on my rv, this winter we are adding two more and rewiring them in a 24 volt configuration. With four l16 6 volt batteries in series, 24 volts and a 3500 watt inverter, I prefer outback units. We do not have any issues with power. This system runs the microwave, refrigerator and sattalite tv. It also powers the rest of the DC appliances in the rv.
Larry Lee says
I have 2 Kyocera 140 watt panels wired in series through a Morningstar 45 amp MPPT controller. Biggest advantage to system is keeping batteries fully charged while unit is in storage as we only travel about 6 months each year.
Thomas Seim says
That is $1000 in equipment, not counting installation. If you are only concerned with draining your batteries while in storage put in a battery disconnect switch for $10 (which is what I did):
Carl Bilodeau says
Base on my expérience a RV should have between 500 to 900watts. Understand 500 watts you will still need a generator.
If you shop around on small ads you should pays 0.80$ to 1$ per watts for the panels. À true mppt controller is 0.50$ per watts. A true sine inverter is 450$ to 600$. I paid a total of 1800$cad for my very powerful 860watt system. Did everything myself.
I have two 300 watts panels + one 255 watts panels. My inverter is a 2000w but should have put bigger since IT is limit for my microwave.
Is there an RV available today with sufficient solar capacity to power all non-engine needs (including heating, A/C, and refrigeration), and with a composting toilet and gray water system?
In other words, an off-grid, off-septic RV
If you are a complete newbie to solar, I suggest reading everything y0oi can, calculate your electrical needs. As a future fulltimer, I’ll be looking for 250W monocrystalline panels, a 60A charge controller and a 3000/6000 inverter. With 1 KW of solar, we’ll do fine.
I’ll find the panels on Craigslist. Amazon for the controller and inverter. Panels will be ground-mounted, for maximum efficiency. I wish that manual solar pointer was still made. Would be a big help. Batteries (LiFeP04, not lead acid) will be acquired from China.
Doesn’t have to be a zillion dollars. I believe our system won’t be more than a couple grand. Never pay an electrical utility bill again!!!
I went solar on my RV. I run everything (tv, coffee pot, microwave, etc) except the air conditioner and electric heater. I try to minimize the power hog stuff like hair drier and microwave at night, tho. I went with a different approach than the 12volt setups most here use. I went with commercial high voltage panels ( typically 36-48volt) instead of the 12volt ones like Renology. . However, you must use an MPPT controller to do this. Basically, the MPPT controller converts the higher voltages into extra amperage.
Go BIG on your cable feeds from the panels to the charge controller. I used 2 pairs of #6 gauge wire. Using 1 pair for now, other 2 when (if?) I add 2 more panels.
My setup: 2 315watt panels, Morningstar MPPT60, Trimetric battery monitor, Samlex 3,000 watt inverter, 2x costco 6volt true deep cycle batteries (Trojan clones). Everything except the batteries were bought off Craigslist, Amazon or EBay. All in under $500. I have seen a high output of 54 amps on a good day!
I installed my panels on the roof, such that I can add 4 more, if needed. Will have to build a battery box if I need 2 more golf cart type batteries. However, I am researching getting some used automotive lithium batteries and going from there to save weight and add capacity..
Solar can be done inexpensively if you can do a lot of the work yourself. If you fear electricity, but are handy, you can do what you can, then have an electrician or solar guy moonlight for a couple of hours to finish it off for you.