Frequently Asked Questions about Solar
When you move into a van, one of the best thing you can do is get a solar power system so you can have all the power you need. However, for the majority of us the world of electricity is a mystery we want to know as little as possible about. All we really care is that when we flip on a switch, the light or appliance comes on. If it doesn’t, we replace it or call an electrician. But now that we’ve decided to be nomads in cars, vans and RVs and need a solar system for power, things get a whole lot more complicated.
Believe me, I understand your fear and frustration when it comes to learning and installing solar power. In 2009 I decided I had to have solar on my van but I couldn’t afford to pay someone to do it for me–I had it do it myself. But it was all just so hard to understand!! So I set about trying to unravel the mystery and began to read everything I could find on the web. It was a long hard process but six years later I have a good grasp of it. By far the simplest way to have solar is with a Renogy Portable Suitcase 100 watt system. Anybody can have it running in 5 minutes! Get it from Amazon here: Renogy 100 Watts Foldable Solar Suitcase
Today, I want to strip it down to its most basic elements and try to give you simple general instructions (with as little technical jargon as possible) on what to buy and do with it. In later posts I’ll go into more detail but still try to use a minimum amount of technical jargon to help you have a base understanding.
Q. How Much Solar do I need?
A. My simple answer is to buy all you can afford. Solar has gotten cheap enough that the chances are you can afford some, but maybe not all you want or need. So just start with all you can afford and leave room to add more as you grow. 100 watts really is the minimum and most people find that 200 works very well for them. I recommend 200 watts for most people. Buying a complete kit is by far the easiest way into solarm I recommend these: Renogy 100 Watts Solar Rooftop Kit or the Renogy 200W Mono Solar Rooftop Starter Kit,.
This chart shows what each system can reasonably run so you can decide which one works best for you:
Q. What if I get too much?
Ain’t gonna happen! I’ve talked to thousands of nomads with solar and I’ve never heard anyone say they had too much solar and wish they had bought less! On the other hand, most have wished they had more! Why? What seemed like plenty of power during great weather in summer will be too little during long storms or in winter when the sun is low on the horizon and the days are much shorter. The key is to size your system for when there is the least amount of sun. Far too many people buy too little solar and then are very unhappy with the results.
Q. Is there any limit to how much I can get?
Yes, it’s self-limiting. If you’re in a van there is a limited amount of space on the roof for panels or inside to carry the weight and size batteries for a too-big system. Generally, 500 watts (or less) is probably the upper limit of what you can fit on the roof of a van and that is probably the most any of us can afford or want. If you live in an RV you probably need more and should have room on the roof for it.
Q. What happens if I get too little?
Too little solar will be hard on your batteries and often leads to premature failure because they don’t get fully recharged every day. Batteries are so expensive you want them to last as long as you can and an abundance of solar power means your batteries will last longer and save you money in the long run. Would you rather spend $500 (or more) on battery replacement every two years, or every ten years? An abundance of solar will give you longer life out of your batteries.
Q. There are so many choices! What brand should I buy?
Let me just flat out say I recommend Renogy as the brand you should buy. Let me add that I don’t make a penny from them but I’ve known many people who bought Renogy systems and they’ve all been pleased with both the product and the service and support after the sale. Right now they’ve found the sweet spot of the very best balance of good quality products and very low prices. If you buy one of their kits you’ll get nearly everything you need in one reasonably priced package. For some reason Renogy doesn’t include fuses in their kits, order this one and put it in the positive wire closest to the battery post: Water-resistant In-Line Fuse Holder – 10 AWG
Q. What should I buy if I want better quality or more features?
If you want to take the time to learn everything you need to know to assemble your own parts and pieces, then you can buy better components for a little more money. But there is a steep learning curve to make your choices and put it together. When you’re done it will be a better system, but whether it’s worth the extra learning, time and money it cost you, only you can decide. It was for me, I’ve got almost 600 watts in three complete systems and they are all better components. If you want to go up to the next level of quality and features, these are my recommendations:
- Solar Panels: I own two Kyocera solar panels because they are the highest quality you can buy at about the lowest price. Not only that but they are assembled right here in San Diego, CA. However, there are many other good brands so if you’re on a tight budget don’t feel bad about buying them on price alone.
- Solar Controllers: The premium brands of solar controllers are made in the USA, and have better support. I own two Blue Sky controllers and highly recommend them, but there are many other very good ones available like Morningstar or Midnight Solar–you won’t regret buying either of them. They are made in America, offer more advanced features and usually have longer warranties. Customer support is generally better as well.
Q. I want to use all the electrical appliances that I used in my house, can I do that?
No, it simply isn’t practical to do many things from solar in a van that you could easily use in a house. You don’t have enough room on the roof for the panels or inside for the batteries they require. If you’re in an RV it may be possible but for most of us the cost, space on the roof and weight of the batteries make it totally impractical. Even worse, appliances with very large draws are death sentences for your batteries and you’ll be buying expensive batteries every year or two. Here is a list of things you should NOT plan on powering from solar:
- Air Conditioning: You need a minimum of 800 watts to even begin to think about running an air conditioner off of solar and even then it’s problematic. Ventilation, fans and shade are by far your best bet for cooling.
- Heating: you can NOT run space heaters off solar but you can power some 12 volt electric blankets and very small 12 volt heaters can be run off a large enough system.
- Most Cooking: very fast cooking appliances like a microwave, rice cookers or inductions stoves can be run from solar but require large systems, large pure sine wave inverters and battery banks. Cooking is best done using propane.
- Desktop Computers: this is a grey area, a big enough system can run it but in every way it’s better to have a laptop.
Q. What if I can’t afford as much as I need?
Power conservation is the most important lesson any vandweller with solar can learn. If you need more solar than you can afford you’ll have to learn how to do without some things you’d like to have or find another way to power them. During storms or in the winter you’ll need to learn to use less power to keep your batteries happy and healthy.
One important way to do that is to use as much power early after the sun rises as possible. Hungry deep cycle batteries take a bigger charge so charge your devices earlier in the day rather than closer to sunset or after dark. At night, minimize your use of power by doing things like, 1) using LED light bulbs only and 2) if you have a 12 volt compressor fridge, be sure it is at it’s coldest before sunset.
Q. Can I charge my house batteries off the engine if I add solar?
Yes! It’s not only possible, it’s a very good idea because the two work together extremely well. The voltage regulator in your car and the solar controller will read the power coming in from the other and make sure your battery isn’t overcharged by reducing the current going into the battery. But if you aren’t getting enough sun to keep your batteries at 100% full, driving it will take it a long ways toward getting there. Be aware it’s possible it can shorten the life of your alternator.
Q. Can I use a generator and solar while charging off my car?
Yes, the three complement each other very well. I have enough solar that I don’t need a generator, but that’s a personal choice. I had one but sold it because I didn’t want to 1) carry gas for it, 2) change its oil, 3) maintain it, or 4) listen to it. I have solar so I can avoid all those things. You’ll need a smart charger to charge your battery from the generator.
Q. Is it a good idea to buy used solar panels?
Yes, it’s generally fine to watch craigslist for used panels. Of course you’ll want to look it over for obvious damage and check the voltage of the panel to see that it’s very close to what the manufacturing sticker says it should be. If it checks out I wouldn’t hesitate to buy a used panel if it’s a good price. However, often they are overpriced and you can get a new one for about the same price per watt. Unless I was on an extremely tight budget, I wouldn’t buy used unless it was at least 30% off the price of new one. I’d buy a new one instead.
Q. Do I need an inverter?
Probably. Inverters waste power so you want to use them as little as possible, but chances are you will have some 110 volt items you can only power from an inverter. 400 watts is usually enough for most people and you want to wire it directly to your battery and not use a cigarette lighter plug. I’ve had the best luck with Cobra inverters, get it from Amazon here: Cobra 400-Watt Power Inverter with 5-Volt USB Output
You want everything you possibly can to run from 12 volt to be powered directly from 12 volt—especially items that charge off USB and your laptop. Generally you can find a 12 volt charger for your laptop from Amazon or eBay which will save you a lot of power.
I’ll stop here with a basic introduction to solar, in my next solar post I’ll give more specific and technical details.
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Renogy 100 Watts Solar Rooftop Kit
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Water-resistant In-Line Fuse Holder – 10 AWG
This feel right to me. I had not quite 400 watts on my conversion van and it ran my compressor fridge and one cooking appliance. I was careful not to use my induction burner and microwave at the same time. I had a diesel furnace and never tried to run my A/C without hookups. I had an electric water heater, too, but I only ran it for ten minutes (not when cooking) then shut it off as that made the water warm enough for a shower if I didn’t add cold to it. But, if I had too many overcast winter days, I had to go for a long drive so my alternator would recharge my house batteries. Since I was usually in Quartzite when that happened I would make a grocery run to Parker and back and be all set for another stay.
That sounds just right Linda! Most people will be very happy with 400 watts. But even then in long storms you have to conserve or get power from somewhere else.
Will strong winds affect the integrity of those solar panels installed on van / motorhome roof ? what about hail, will it damage them ?
Lucy, winds won’t affect them but if it’s a big enough hail they can be broken but we aren’t talking about normal hail, we’re talking about golf boll and bigger. It can happen but it’s extremely rare.
Thank U, Bob !!
Hi I love your show. I just purchased a 1998 Travel Supreme. Looking to put solar on it, in it. I called the AM solar place in Springfield, Oregon. Heard good things about it. They want to charge me 4,000 dollars for 400 watts in solar panels and 4 batteries. That includes installation only. No inverter or anything. Isn’t that expensive?
With used solar panels, as well as new, I check the amps. I test the panel(s) on a sunny day and bring a discharged battery that I hook up to each panel. You can use this method to cherry pick the best performing panels if you have a bunch of them to select from.
Good idea David!
so am speculating that maybe in full sunlight during the day, with 1000 watts of solar (a goal) that I could run a very/extremely small air conditioner; and not charge any batteries. But this would still mean I want the RV under shade, and using available breeze, and insulated well; to get any effect.
Most people want to do several things with the electricity, including charging batteries for the night. So in reality this is not happening.
Kevin, with 1000 watts you could run the tiniest AC and charge your batteries as well. I know someone who runs his off of 750 watts so it can be done.
When we added solar to our rig it literally changed our lives on the road overnight. Best thing I ever did as a full time vandweller!
My set-up is 300W PV, Morningstar PS-30M and 2 Trojan T-145 260 Ah 6V batteries wired in series for 12V. I also use a Schumacher 400W inverter.
This set-up runs my Engel MT-35 continuously (2.5 amps/hr.), 24″ LED TV, LED lights and everything else that needs power including the Magic Bullet smoothie maker!
This set-up freed us from every paid campsite and made boondocking in locations without power so sweet its incredible! Sometimes you need GPS to find us and even then good luck! We love to get deep in the woods where all the action is at.
I recommend solar wholeheartedly and would NEVER leave home without it knowing what I know now. On the road power is a game changer like nothing else. It allows for a full life.
Since I have done it I have convinced many dwellers to move to solar after they see my set-up in action. We even convinced one big rig fella to add it and he did. To the tune of 3000W! He even runs his little 5000 BTU air conditioner on his system! He has 10 Trojan T-145’s running his rig off grid! What a sight to behold!
It is only two wires to connect and it is so simple. Don’t be scared spend the money and get it running. It will change your life. I guarantee it!
Thanks Marshall!! I agree 110%! Very well said!
I’m mainly thinking about people like me who have yet to set up their systems. I will refrain for now on asking about some specifics I have known people to use, but I want to discuss conservation here because it affects everything else about power systems. Don’t underestimate your ability to conserve electricity. I will give a couple of personal examples.
Many people have never lived without a TV and either cable or urban-level signal, but I encourage experimenting with it. When I had to choose between TV and Internet a few years ago, I chose Internet and never regretted it. Even if you are not comfortable with that, most TV is available via Internet these days, much of it free. For the news followers (like me) out there, stories tend to show up on Internet sources first. That’s in addition to the many other uses of Internet and the non-Internet uses for a laptop or even a tablet.
Also, while this example is more about personal choices, many years ago I lived for a month in an apartment with major electrical defects. I did not dare plug in the refrigerator. By the end of the month, I realized that I can live without refrigeration or a cooler. I eat based on an extreme food budget, but I do not get nutritional illnesses and I’ve been doing this a long time. You may not want to do that, but consider refrigeration and power for it as food costs.
Your examples may not be the same as mine, but think about reducing demand. It will not only save you money, but will also simplify your life. That’s a great goal in itself.
Thanks, those are very good ideas for conserving power.
Excellent information. I love the chart. When it comes to useable information, you rock!
CAE, I have the advantage of being a little dense so I have to have things made simple!
Bob, I believe you have the advantage of been a perfectionist & this is an asset.
My regards: Lucy.
Lucy, there may be some areas I’m a litle anal about, but actually I am the opposite of a perfectionist. I’d describe myself as the king of half-ass.
LOL, LOL funny guy !
” For some reason Renogy doesn’t include fuses in their kits”
I’m sure you know this, but just in case there is some confusion out there, the Renogy solar suitcases DO come with fuses on the pigtail that connects to the battery posts.
Bob, I didn’t know that I’m glad to hear it. I was thinking specifically of their solar kits you mount on the roof, they don’t come with fuses.
I have a Renogy 100 watt suitcase and I love it, love it. Simple, easy and portable so one can move it around. Very happy with my purchase. I am wondering if I can hook up another 100 watts to it and keep just one battery. I am only part time so don’t need all the wattage that other people do.
Thanks Lynn, they really are a great product! Sure, no problem hooking up two systems to one battery.
An extra panel will help your battery charge faster but it won’t actually give you any more energy since that is limited to what is stored in your battery once the sun disappears. Adding a battery gives you more storage space but if you don’t also add a panel you may never get your batteries full. It’s a balancing act.
Linda, you are 100%right it is a balancing act. To make it even more complicated some batteries want a very high charging rate so they need more solar panels. That’s common with AGMs that need to be charged faster that flooded wet cells.
great info, and Calvin’s advice on conservation makes a lot of sense.
It looks like electricity needs go way up when you add a fridge, but the fridge adds a lot of quality and convenience to a mobile life.
Is it true that you need to exercise a generator regularly? What if you only camped in summer? How would you take care of the generator in the winter?
I looked at Sundanzer’s recommendations for their 50 liter fridge. They recommend a 40 watt solar panel with a 54 a/h battery. If you live in a less sunny area, I would increase that a bit. 100 watts of solar and 100 a/h battery should be more than enough. 100 watt solar panels aren’t much more than 40 watt panels, too. That is not much solar and takes up very little room.
Leaving a generator set for years at a time would be bad. Starting it up every few months would be a good thing. Winterizing any motor is easy. You could go through the process of draining the fuel before every winter, but I don’t recommend that because it is more work than necessary and doesn’t work as well as the following recommendation:
Add Sta-bil to your fuel. It can be that simple. Mice, wasps or other insects may nest inside your generator, but if you store it in a box, that very likely won’t happen. You should change the oil at least once per year to get rid of the condensation that builds up inside the motor.
Solar is great, but in some ways it can’t do what a motorized generator can. A generator can be a great addition to a person’s electrical needs/wants. Going with just a generator and not solar would be a poor choice for almost anyone. The benefits and ease of solar are truly amazing.
Generator manufacturers recommend you exercise your generator once a month under load to keep your warranty valid. That means running lots of things to maximize the power draw on the generator. Or running one air conditioner. When we had a generator we would spend one day driving with the generator on, running the A/C, so as to not irritate neighbors with our generator.
What you need to do when storing it depends on the generator. Sta-bil is not what you do for a diesel generator.
That need to exercise then winterize a generator is what made me decide not to have one in my conversion van. Yes, I had a couple days when I wished I could use one to refill my batteries but that happened so seldom as to not make it worth the hassle for me even though I had an all-electric house except for my diesel furnace.
Ming, yes, it’s very true! If you winterize the genny properly it will be fine over the winter, but you should do the whole thing, drain the gas, pull the plugs and shoot oil in them and then put the plugs back in and turn the engine over.
You can just do the Stabil and it will probably be fine but if you are going to be doing it every year, I would do the whole thing.
In the winter they really don’t use that much but in the summer they will do draw a lot more.
thank you very much Canine, Linda and Bob on your generator advice. My dilemma is that I do a lot of camping in the trees and the cloudy PNW. Many is the trip where I did not break out the solar panel at all. On others, I was chasing a little patch of sunlight around the campsite with it, moving it every 15 minutes, or backpacking it and the battery packs down to the beach or riverbank. Easy enough to do with the small panel I have now, but I won’t want to do it with a larger system.
I guess I will have to add to my system slowly and see what works and what I need to buy. It is interesting to note that the full-timer bloggers that I follow run into the same problems when they travel to my neck of the woods. Everyone seems to sooner or later need to pay for a campground with electricity, or travel away from the area in search of sun to refill their batteries.
I would love the lower maintenance of a solar only system, but I’ll have to see if I can make it work, especially if I add a fridge and electric bike to the travel gear!
Draining the fuel or not is a personal preference. Don’t feel bad if you choose one way or the other; professionals recommend both ways. The reason I prefer not draining the fuel and using Stabil is gas lasts longer in larger quantities. All things being equal 500 gallons of fuel will degrade much slower than 1 quart of fuel. In the carburetor there are tiny pockets of fuel left even after draining the tank and turning the engine over several times. That small droplet of fuel without an additive is more likely to varnish and clog the teeny tiny fuel passages. Even a clog as thin as a human hair in a transfer port can make an engine run horribly if at all. That’s how I figure it.
Pouring in Sea Foam while it’s running or pulling the plugs and shooting oil in the cylinder is a very good idea for sure. That is something I should’ve mentioned.
Stabil makes blends for diesel, too, but Linda’s point is still a very good one. Make sure you are using the right product for your specific genny; that’s important.
Since your in the PNW, that can be tough for solar use. I love being in the trees, but at least I don’t have to deal with the cloudy weather where you are at.
Stabil is great stuff and it goes in every drop of gas that ever goes in my generator. No exceptions!! Thise small engines hate water and the ehtanaol in our gas loves water, I ALWAYS, 100% OF THE TIME, USE STABIL IN MY GENNY!!
Ming, you have to adapt to your envirnoment so for you a generator would be very important!
drat, thought so. Thanks for confirming, and thanks guys for demystifying the care and feeding of these beasties. The small Hondas really are quite good for not being a huge pain for your neighbors. I wish more people would get them.
Have you heardaboutthe watergenerator? Runs on waterand is beingsold in Canada. A watergenerator couldsolve the problem with AC. The price is like 5,000but if the lifetime is long, it will be worthit
Alex, that is something to keep an eye on.
I think one of the first questions to consider when weighing the design of your solar electric system is do you really want your panels on the roof? Once the panels are on your RV roof parking in the shade – to minimize your air conditioning needs – obviously reduces your panel efficency. Of course some folks want it all! Given this I think the portable set up is the way to go. My set up is a Class C with a 125 watt panel on the roof (It had that set up when I bought it) I tow a small cargo trailer with my Yamaha scooter in it(instead of a toad) and on the roof of the cargo trailer are 2 – 240 watt panels. With this set up the cargo trailer can be set in the sun and the RV in a shadier spot.
Rick that is an ideal set up with panels on both the van and trailer. That’s also what I have but I live in the trailer in the winter and in the van in the summer.
What do you use to transfer the power from the trailer to be used in the Class C? DC has voltage drops over length of wire so the cable has to be pretty healthy. Just curious because it’s such a good idea.
I use the shore power cord from my RV. It plugs into a 30 amp plug mounted through the trailer wall. The plug is attached to a heavy Guage wire with a plug at the other end that plugs into my inverter. Not sure what the voltage drop is but I’m getting all the power I need.
Alright, I have a pop up camper that I would be interested in adding solar to. I am a little hesitant to put holes in the roof. Is it possible to just lay a couple of solar panels on the roof prior to cranking it up and just secure them with a few bungee cords to protect against winds and add a bit of security?
Brain rather than do that I would get the portable suitcase because it’s so much easier to handle. But yes, you can get regular panels and sit them out flat on the ground or just put a rock under one end to get it to tilt. You could even mount it on hinges on the side of the trailer and tilt them up with an arm to get the right angle.
You’re only limited by your imagination.
Thanks for the input Bob. I have two 6v GC batteries at 220 AH each. I was looking for at least two 100w panels along with the MPPT controller. Is it possible to use two or more suitcase models together? Maybe that is gross overkill for my available battery storage, but I guess I would rather have a bit too much than a bit too little.
Brian, the general rule is 1 to 1, so if you have 220 ah of battery you need at least 200 watts of solar. Two suitcases would work fine and they can both be used at the same time no problem. I don’t think you get a choice of controllers with the suitcase, but I could be wrong, contact Reonogy and ask them.
Alright, last question I hope. Would it be wise when purchasing two 100w panels to go ahead and purchase the 40a controller in case of future upgrades?
Brian, If memory serves it isn’t a whole lot more money so if you think there is a pretty good chance you will add more panels later, I’d say Yes, go for it. Having more options is always a good thing!
40 amps is a lot for a van. You could never fit enough panels on your van roof to use the whole 40 amps. Go with the 200-250 PV and a 30 amp PWM controller will be plenty.
Mashall, I have a friend who mounted two Kyocera 315 watt panels on his roof and that’s a little more than 50 amps. I also recommend getting a controller a little bigger than your panels so if it ever over-volts it will be okay. My friend needs a 60 amp controller in his van.
For the great majority of people, 200-250 is enough, but there also many people for whom it is not enough. It was not enough for me, I currently have 580 and have no regrets about a bit of it. Chances are if you get a week of storms in January most people will be wishing they had more.
Rather than an inverters is it possible to get a “power stick” to run multiple 120 volt devices from the car battery? (and probably an additional battery and solar)
Michael, I’m sorry, but I don’t know what a Power Stick” is. Can you give me a link to one?
This is the best answer I found for “what is a power stick”. http://powerstick.com/main/faq/
These ‘power sticks’ look tiny! There is no indication of their Amphour rating in the FAQs on the company website but given they only charge a cellphone, not even a laptop I’m sure its miniscule..
Hence an inverter is neccessary for anything more than a cellphone charge!
(Aside: forget ‘power sticks’ but maybe a ‘power wall’ will be making its way into an RV /van sometime soon though! Thanks Tesla..)
Ok Bob, you have 580 watts of panels. How many batteries do you have and what Ah of each?
Steve, I have 6 golf cart batteries totalling 660 ah.
Bob, we are in Tucson headed to Quartzsite Tuesday, where would be the most economical place to buy solar on our way there. probably a 600 watt system.
Thanks for the blog post, how can I make is so that I receive an email every time you publish a new article?