Author"s Notes:I am a experienced renewable energy (RE) author and also avid flyfisherguy, and also I"ve lived 12 miles off the power grid for the last 15 years, powering my house entirely from solar and also wind power. I receive a ton of email each week with concerns around the basics of developing RE power units, ranging from tiny systems for a camper trailer to big residence power devices. This article is my attempt to describe the basics of it for a complete beginner. Hopefully I"ve removed many of the jargon, and also at least defined all the jargon that"s supplied.

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Yep, that"s a ring from a rising trout in the reduced righthand corner! We recorded and also released over 200 trout on that 2-day camping trip. It was the shakedvery own cruise for our brand-new old pop-up camper and its new solar power device. The mechanism worked great!


Our vintage 1968 Starcraft pop-up camping trailer, the "Sally Ann."

Unfortunately for his employers at kosid.org, DanF is a trout bum. That indicates that at specific times of the year, he is "unavailable" for work bereason of a specifically nice insect hatch on our house waters here in Northern Coloraperform, or indeed anytime all his hrs spent staring at a computer display screen begin turning his brain into mush and making his eyes go googly.

DanF"s employers, who are probably currently analysis this new internet page, are specifically advised to note how regularly this problem occurs. He apologizes sincecount to them for trying to convince them last fall that our firm web server cluster facility was located on the shores of Hohnholz Lakes on the Laramie river for better defense, and also that weekly trips up tbelow were forced for constant servicing. In reality, our servers are situated alengthy the North Platte river in the stretch between Seminoe Resevoir and also Pathfinder Resevoir in Wyoming, often called the "Miracle Mile."

According to the finest medical research obtainable, the just sure cure for these exhaustion and also "googly eye" afflictions is a couple of days of fishing. Since DanF"s Dad has a vintage 1968 Starcraft pop-up camping trailer easily accessible for usage, DanF figured that installing an easy solar power system in the "Sally Ann" and composing a internet web page around it would certainly be an excellent method to capture the late summer damselfly hatch close to Walden, Coloraexecute and also the October caddis hatch in Lowell, Idaho and still pretend that he was actually working the totality time!

System architecture considerations

(and also how we addressed them)

How a lot power perform we really need?Not a whole lot for us--we go camping so we deserve to flyfish, and get amethod from all the modern-day contraptions and also their noise. We need lights at night, a portable radio / CD boombox, and also battery chargers for our 2-way radios, digital cameras, and GPS systems. Bright lights are necessary if we are tying trout flies in the evenings. If we lug our vintage Grummale canoe, we perform use some serious power via the electrical trolling motor--even more on that later on.

There have been various other people at certain campgrounds we"ve stayed at recently that seem to need satellite television dishes, huge display TVs, electrical Mister Coffee devices, electrical refrigerators, and also all kinds of other stuff that we are trying to acquire ameans from. They put all this stuff right in their campers! We are boggled by this mindset towards wasteful power use, and the noise, fuel price, and also maintenance determinants of running an infernal combustion engine at the edge of the wilderness. Perhaps we are Luddites, however we do like our tranquility and also quiet. That"s why the "Sally Ann" is powered just by (silent) solar power, with the choice of a (aacquire, silent) shore power link.

12 volt DC versus 120 volt AC power systemsA few years earlier, simply about everyone that powered a camper (or tiny cabin, for that matter) from solar offered a 12 volt DC (12 VDC) system--that"s a direct feed to your cigarette-lighter-plug devices off of a 12 V battery or financial institution of batteries. Problem is, 12 volt power has actually several losses in the transmission, and also to reduce the losses things need to be wired through very thick, expensive wire that"s hard to work-related with. That"s why most 12 VDC lights and appliances are very tiny...a typical vehicle cigarette lighter plug and also outlet can"t manage much power before becoming hot from electric resistance and melting your dashboard, or (hopefully) blowing the fusage first.

In the last 5 years, "power inverters" have dropped significantly in price and come to be widely available--the internet, truck stops, the neighborhood NAPA auto parts shop, everyone sells these gadgets now for cheap. Most are roughly $150 or less. They transform 12 volt DC power right into 120 volt AC power, additionally known as "home present." That"s what"s accessible at every electric outlet in your house in town! If you are not in the USA, inverters are obtainable international for every various electric system, you simply have to buy the right one for your nation. With an inverter, instead of buying all brand-new light bulbs, boom boxes, toasters, radio/GPS/electronic camera battery chargers and also such for your 12-volt camper, you can use the stuff you currently have, or buy brand-new ones from K-Mart for cheap. A typical (and also very efficient) compact fluorescent (CF) light bulb for 120 volt AC house existing will expense you only a couple bucks at Home Depot or the regional supermarket. A 12 volt DC variation will price you at leastern $10 per light bulb, be available only online or at a specialty RV shop, and probably won"t be developed by a significant US or European manufacturer from whom you deserve to acquire a remoney if it does not work ideal.

We made a decision to go via 120 volt AC inverter power for the Sally Ann. A quick expedition to K-Mart, and also all our lighting and appliance requirements were met at low price. Buying all those devices aobtain for 12 volts DC would certainly have actually cost much even more than the cost of the inverter! We finished up with a 1500 watt Whistler inverter, much more than we require, but it was obtainable cheaply used. If we were to actually RUN a 1500 watt load from it, our bit marine deep cycle battery would be dead in much less than an hour. To pick the correct dimension of inverter, full up the power draw in watts for all the lights, appliances, and various other gadgets that you can be running all at the very same time, and also pick an inverter with a "continuous" power output of a couple hundred watts above that. "Surge" power output that"s advertised is not a beneficial spec--if you ever reach this number in the power you are utilizing, your inverter is also little. Also, be certain to follow the inverter manufacturer"s references for wire size from your battery to the inverter--this wire needs to be both thick and functional.


1500 Watt Whistler inverter set up under counter, to keep it safe from water drips, bourbon and beer botches, chili spills, and tipsy flyanglers.

Power versus Work versus EnergyFolks frequently gain perplexed around the correct devices in which to measure power intake. Watts meacertain power being supplied or gained at any type of offered prompt. But Energy is what"s many essential to you, not power-- Energy is power measured over time. It doesn"t issue that the huge TV in your camper offers 200 watts. The genuine problem is how many type of hours per day you have the point on! So, the appropriate systems to use are watt-hours or amp-hours (A/H), not watts or amps. Ten amp-hours of use implies that you ran your boombox that draws one amp for 10 hours--or that you ran your huge TV that draws 10 amps for one hour. You gain the principle.

Appliances and also lights are constantly rated in watts, and also they are constantly noted on the ago for just how many watts they draw at complete power. Batteries are rated in amp-hours of capacity. The only math you should carry out for developing an easy RE system is converting watts to amps. Then you multiply by time to acquire amp-hours. Watts = amps x volts, and also amps = watts / volts. So, a 60 watt light bulb powered from your inverter will usage 1/2 amp at 120 volts AC (60 watts / 120 volts = 0.5 amps). But your battery is 12 volts! So to power this bulb, you should execute the math for what"s really coming out of your 12 volt battery-- 60 watts / 12 volts = 5 amps.

Choosing the batteryThe Trojan CB-27 battery we mounted in the Sally Ann stores 100 amp-hours of power. BUT you never, ever want to take any type of battery down listed below 50% of its capacity--the majority of batteries can only do this for you a couple dozen times, then they are ruined. For lengthy battery life (2 years or more) do not take your battery dvery own by more than 30% of capacity. If you can afford to rearea your battery yearly or 2, you have the right to be more abusive.

The 30% discharge pointer states we can typically draw dvery own the battery on the Sally Ann by 30 amp-hours, with occasional drops to 50 A/H (half capacity). So, for decent battery life we could run that massive 60 watt light bulb for at most 10 hours to take our battery dvery own to fifty percent capacity (100 amp-hrs / 5 amps = 10 hrs.) If we ran our cute little 1000 watt electric heater from inverter power, the math would certainly be: 1000 watts / 12 volts = 83 amps-- a little over fifty percent an hour to the "battery critical" condition of 50% discharge. Cold Cranking Amp (CCA) ratings on batteries are usemuch less for measuring storage capacity. CCA is for automobile engine beginning batteries, not RE units. The number you should look at is amp-hours (A/H). You could have to ask your battery dealer for this information--it may not be printed on the battery.

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You can incorporate multiple batteries for more capacity, if you have the area. Standard "marine deep cycle" batteries are a great option for a tiny system, they withstand deeper discharge much much better than automobile engine starting batteries. For a bigger camper or a cabin, you could consider golf cart batteries (T-105s), which have to be set up in pairs because they are 6 volt, not 12 volt. Home or cabin power units frequently use 6 volt L-16 batteries, which have many capacity and are very durable--however they are huge, hefty and expensive, and typically a lot even more than have the right to be fit into a camper. So-dubbed "gel cell" batteries have the benefit that they have the right to be tipped over without shedding electrolyte, yet in general they are much more expensive and delicate than the run-of-the-mill "flooded lead acid" battery we supplied in the Sally Ann.


Trojan CB-27 battery in the battery box, via lid removed. Inverter is installed over it. 100 amp-hours capacity. Keep in mind just how thick the inverter wires are -- this is vital. The battery box is screwed to the floor so that nopoint can move.

Lighting choicesA 60 watt incandescent light bulb wastes even more power as warmth than it transforms right into light. Think of any incandescent bulb as a space heater that produces light as a byproduct! Fluorescents (FL) and also compact fluorescents (CFs) are FAR even more reliable, and they have to be the only bulbs you also consider for an RE power mechanism. LEDs are additionally an option--they are not very efficient (despite many kind of advertising claims), but they perform emit the majority of of their light in one direction, eliminating the need for reflectors. Our lights are a pair of 7 watt compact fluorescent (CF) bulbs, plus a CF fly tying lamp that provides 13 watts, for a full of 27 watts via all lights on. That"s 2.25 amps at 12 volts, so we could then run all these bulbs at the same time for 13 hrs without damaging the battery (30 amp-hrs / 2.25 amps = 13.3 hours.)

The solar panelWe didn"t desire any glass in our solar panel because of lengthy drives on bone-jarring dirt roadways, so that ruled out all the normal models intfinished to be installed on homes. My remote house in the hills runs on such solar panels, yet we feared breakage in the time of our driving. We additionally did not want to permanantly mount the panel to the roof of the trailer--we"re lucky the old girl does not currently have a leaky roof, and also placing holes in it sounded like a poor concept. Plus, a level mounted solar panel does not execute much good unless you are near the equator--for maximum power generation, solar panels need to be encountering straight at the sunlight.

Tright here are some really cool flexible solar panels available--you deserve to roll them up for storage, and also even mount them on the top deck of boat and also walk on them--yet they are much even more expensive than traditional models. For solar panels, it all boils dvery own to dollars per watt. Standard, "single-crystalline" or "poly-crystalline" panels mounted under glass for houses run about $5 per watt appropriate now. "Amorphous" panels are up about $6-8 per watt, and functional amorphous panels have the right to reach $10-12 per watt! Amorphous panels have the disadvantage of making a lot much less power per square foot than single or poly crystal, yet have actually the benefits of not being so brittle and fragile, have the right to be constructed into versatile panels, and also are affected much less by partial shading.

We couldn"t see the logic in paying more for one functional, roll-up solar panel than what the pop-up camper expense us in the first place! So, we compromised--our solar panel, made by Innergy and also mostly offered in remote river gauging stations and various other telemeattempt applications, offers single crystal cells embedded in fiberglass instead of under delicate genuine glass. It offers 30 watts of power in full sunlight, and is only 19" x 36". It came in at $5.97 per watt, a lot better than roll-up models, and it makes even more power for its dimension than amorphous deindicators. We built a simple aluminum framework for it that we can prop up close to the camper after we arrive at a remote campsite. Shading is a large factor in solar panel output, also one branch shading part of a solar panel reduces output to nearly nothing. With the 25 foot expansion cord, we have the right to put the camper in a shady spot and also set the panel in the sun.


Our glass-much less, fiberglass installed solar panel through homedeveloped aluminum framework. The tree shading shown in the photo is BAD--the panel is hardly putting out any power bereason of the shading.

Solar panel wire sizingRemember that we debated previously exactly how challenging 12 volt DC power is to move around compared to home current? Suitable wire thickness is important in connecting solar panels or else much of the power coming in will certainly be shed as heat (simply favor in a toaster, just the solar panel wire will not even feel warmth to the touch.) Wire losses of around 5% of your panel"s output are acceptable. Rather then go right into all the math, the most basic method to carry out it is Google up "wire dimension chart" online, or obtain a published one from any type of large renewable power dealer"s magazine. Ssuggest look up your panel"s output in amps at 12 volts, and also check out the maximum distance you can go on specific gauge of wire. Exanxiety cords are great for this, yet be certain to check on the package what the actual wire size inside the cord is. Usually, 10 or 12 gauge is the biggest obtainable at the hardware keep...get the ideal and also thickest you deserve to afford. The more power your panel puts out, the thicker the wire you need and the shorter the distance you have the right to go. For us, a nice 25 foot, 10 gauge extension cord price about $25 and also has actually exceptionally little bit loss at just 2.5 amps from our solar panel--we might add a couple even more solar panels later and also still have the ability to use this cord through under 5% loss.

Solar panel controllersLarge home-sized solar power units constantly have controllers to save the battery bank from overcharging. In our tiny system, we did not encompass a controller. The reason is that standard "flooded lead-acid" batteries are not damaged at all by "overcharging" -- defined as proceeding to pump electrical energy into the battery after it"s complete. All that happens is that the battery electrolyte level drops more promptly as the battery bubbles. If the electrolyte level drops below the top of the plates, the battery is ruined. It"s important in any RE power system, with a controller or without, to examine the battery electrolyte level monthly and refill it through distilled water when it gets low. In our case -- we"ll never before have actually that battery bubbling on a fishing expedition, we use also much power eexceptionally night. When the trailer is parked at residence waiting for the following trip, we plug in the solar panel for a day or 2 each week to save the battery topped off. If your battery is bubbling, it"s no difficulty -- however do not smoke around it, and be sure the hydrogen is correctly vented to the exterior. In a camping trailer power device, the only time the battery could be bubbling is when the trailer is in storage for the winter with no power intake. If you for some reason made a decision a gel cell battery, a controller is REQUIRED, and also will expense you $50-100.

Back to input vs outputWe just did all that math about how a lot you have the right to draw dvery own a battery. Now look at our input from the solar panel (30 watts, 2.5 amps) versus the output from our lights (27 watts, 2.25 amps.) Here in Northern Coloraexecute, an excellent clear day offers an average of around 6-9 complete sunlight hrs on a panel, it varies substantially by seaboy. Multiply that by the amps output of the panel to number exactly how many type of amp-hours are coming in. 30 watts = 2.25 amps x 6 hours = 13.5 amp-hrs (winter), and also for 9 hrs of solar expocertain (summer) it"s 20.25 amp-hrs. That"s not also bad--we could run our 27 watts of lights for 6-9 hours at night after a sunny day. What if it"s overcast, or rainy? Solar panels put out virtually nopoint unmuch less they are in full sun. After a couple of cloudy days, we"d be dipping deep into the batteries capacity to run our lights for 6 hours a night. That"s wbelow shore power can be handy!

Renewable energy versus shore power

In a home in tvery own, you"d call it "grid power" rather of "shore power." It"s your fundamental electric outlet into which you deserve to plug your camper electrical mechanism. Most campsites that administer shore power likewise provide shore water pressure. This is absolutely worth the little amount of money it prices per night! Besides having drinkable water under push hooked best into the trailer, an easy 10 amp battery charger from the auto parts save have the right to be running at any type of time we are linked to shore power -- that 10 amps coming in is prefer having actually 4 of our 30 watt solar panels running at as soon as. Even so, the cute little 1000 watt electric heater we bring along to heat up the camper while making early-morning coffee is simply NOT feasible to run off of a renewable power system, no issue how many kind of solar panels and batteries were mounted. We run it off of shore power just. It"s the exact same in town--electrical arrays, water heaters, area heaters and such use far more power than also a huge renewable power system could carry out.

Is a carry switch needed?

All a transfer switch does is switch your electrical outallows from shore power to inverter power and also ago again. Some are automatic, some are hands-on. All are expensive. To save money, we simply wired up a pair of outallows in the Sally Ann--one is for shore power (if it"s available) and also one is for inverter power. Simple, cheap, and deserve to cause no confusion if properly labelled. The just point an inexperienced operator would certainly have to remember is to NOT plug the 1000 watt electric heater right into the inverter output--shore power only for that power hog of a (exceptionally handy) gadget!

I already have actually a generator, will it help?

You bet! In a remote campwebsite wright here there"s no shore power, a generator might be really handy. And the battery device means that you might not have to run your generator late at night to watch TV--you might instead boost your battery with the generator in the time of the day, and store a silent campground at night by running your TV off of the inverter. In our situation we"d ssuggest plug the generator into our shore power input, and both run lots directly from it, and use the continuing to be generator power to charge our battery via the standard NAPA battery charger we haul in addition to us. Get the greatest battery charger your generator can take care of and that you have the right to afford. Generators give you the many watt-hrs per gallon of gas when you run them at 50% of their rated fill or more, and run time will certainly be much less to fill your battery as soon as utilizing a big charger.

How about water pressure?

Once aobtain, we preserved it straightforward. Tright here was currently a standard camper-style water faucet over the sink in our camper. If there"s shore water pressure available, we press down on the take care of to obtain water. If we are utilizing water from our self-had water cistern (a brand-new, clean, food-grade, white 5-gallon bucket) we pump manually from it by means of the exact same handle. An electrical water pump would have been an alternative, but adds even more power use and also possible reliability troubles to the water mechanism. It would certainly be irritating to be without water just bereason the battery was low, with no sunlight or shore power to charge it ago up.

What about the trolling motor?

On some lake fishing trips, we carry our vintage Grumman canoe and also small electric trolling motor along. It"s straightforward to drainpipe that battery method down through just a couple of hours of flyfishing, particularly in windy conditions. So, we made a decision exactly the same battery for the trolling motor as we did for the trailer -- they fit in the same battery box and hook up the exact same method, so we can conveniently exreadjust the trailer battery for the troller. Shore power via a battery charger or a direct connection to the solar panel are the finest methods to charge up the trolling motor battery. Don"t try to run your 120 vac battery charger from the inverter to charge the trolling battery! You"d be converting 12 vdc to 120 vac ago to 12 vdc for charging, with losses eextremely step of the method. It"s a lot even more effective to charge the trolling battery from shore power or direct solar...that"s the major reason we made it straightforward to swap batteries in between the canoe and the camper.


You can spend lots and numerous money on a solar power mechanism for a camper. In truth, I wish some of those folks with noisy generators on our last fishing expedition had done so! The problem is, they would HAVE to spend a lot of cash to run all those power-hogging tools off of solar. The very same difficulty plants up in designing a renewable energy system for a residence or cabin--the even more kilowatt-hrs of power you usage each day, the even more batteries and solar panels you require. Conservation is the key--it"s estimated that for eincredibly dollar you spend on energy conservation, you conserve $3-5 on the expense of the RE devices required to power your stuff. If we"d used incandescent light bulbs in the Sally Ann, our possible run time before the battery was empty would be about 6 times less! The same for TVs, computers and also anypoint else you must run in the backnation. LCD screen TVs have actually very low power draw compared to normal models, as do lappeak computers. Use an old-fashioned stove-peak toaster rather of an electrical one. Install a propane fridge instead of an electrical one. Pick which appliances you use on a pilgrimage, depending on whether you are hooked right into shore power or not. The electrical toaster cooktop is FINE on shore power, but not on solar! Microwave ovens are surpincreasing --- they usage lots of power (800-1500 watts) however are just on for a minute or two, so a small microwave is perfectly feasible on solar power.

The key to using renewable energy, and also one excellent advantage, is that you MUST be mindful of your power usage at all times! When you rerotate residence, you"ll unexpectedly be conscious of all the power you are wasting eincredibly day. You might also rotate into a "power ogre" like me, roaming the residence finding TVs and also lights that were left on and shutting them off!