For my little QS6's battery what kind of solar panel or wattage do I need for 4-5 days?
Thanks,
Kellye
I use a 10w battery tender panel. Effective and easy. Not sure if it would be enough to keep yourbattery topped for 4 or 5 days though since i also use a generator for a short time each day
http://www.amazon.com/Battery-Tender-Watt-Solar-Charger/dp/B004VJTUU2/ref=sr_1_12?s=automotive&srs=2582981011&ie=UTF8&qid=1455334821&sr=1-12&keywords=Battery+tender+solar
[font size="3"]What do you have that runs on the battery? I can only see a light and a USB charger. Do you have the propane package with a furnace?
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I've been looking into this myself. besides adding another 12v battery, I was looking at solar recharging. So far, with absolutely no experience, i like the Zamp systems.. But, so far I've only used the lights and 12v fans that came with the trailer.
i'm probably 75% off grid with just the need for lights, fan and charging for phone and maybe a 12 volt coffee brewer. the guy at camping world tried to sell me a $400 solar panel. i just don't think i'd need that much??
That's seems like a minimum solar recharge to me actually. How many watts was it?
A fan, if run over night can actually draw a lot more amp hours than you would think. A coffee maker I belive is also a high amp draw even if it's just a relatively short time. Lights can be minimized if you use LEDs though.
If you have a good quality battery, or even better 2 6v gold cart batteries, you could get away with a minimal solar panel but it may not fully recharge your system in one day.
It all comes down to Amps used vs Amps charged.
[font size="3"]I don't know all the fans available out there, but a FanTastic vent on low speed only draws 1 Amp while moving a lot of air. Running for 12 hours that's only 12 A-H. That should be typical of small fans. LED lights should draw ~ 0.2A so are minimal. I would think a max of 15 A-H per day would be very adequate for small trailers. I would look at solar panels around 15-20 watts. When added to a fully charged battery that should last the 4-5 day mission and cost a lot less than $400! The first obvious solution would be the two 6V golf cart batteries, but I don't know if there is enough room on the smaller QSs. Need some input from current QS owners here.
On the 12V coffee brewer, that seems a task better left to a small butane/propane stove. Coffee brewing is a tall task for a 12V battery. A quick look at 12V coffee makers doesn't find many good[/font][font size="3"] reviews[/font][font size="3"].
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I bought a folding 80 watt charger years ago for our 6.0. It takes care of keeping the phones and tablets charged and running the fan at night. Also all interior lights where converted to LED and the battery upgraded to an AGM battery. Which ever solar charger you get make sure it has a control unit. I also got an extension cable for the solar panel so I can park the camper in the shade and the panel in the sun.
[quote source="/post/18662/thread" timestamp="1455342018" author="@kelkat"]i'm probably 75% off grid with just the need for lights, fan and charging for phone and maybe a 12 volt coffee brewer. the guy at camping world tried to sell me a $400 solar panel. i just don't think i'd need that much?? [/quote]We really need better answers to give better advice.
What kind of lights, how many for how long ? Ditto the fan. Using Charlie's data (1W vs 0.2W) 5 lights will be the same as one fan.
Are you just wanting to keep the phone alive for 4-5 days with no calls ? Your phone may well live that long on its own, and get a $10 USB battery stick "just in case". Or are you streaming video or music ? For how many hours a day ? You may be dropping the phone charge below 20% twice a day.
How many watts for the solar panel ?
Keep in mind that the wattage rating of the solar panel is in "ideal" conditions. Full sun, straight on the panel. Will that be your weather ? Every day ? What time of year ? Even if you need 15W, it may take a 50W panel to throw off 15W under your conditions. Or even less.
I think the big pull, however, is the coffee pot. That's 500-1500W draw, for 10 minutes give-or-take.
[font size="3"]A few comments: The 80 watt panel is certainly adequate, even overkill, but it does have the advantage of rapid recharge with limited sun or time. Something of that size will definitely require a charge controller as stated. The advantage of a smaller panel, in addition to lower cost, is it will not require a controller if used in a typical daily routine and can even be used as a maintainer if no shore power is available during storage. Due to the mysteries of physics and rating schemes even a 20W panel will only be delivering ~1 Amp in direct sunlight.
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agreed the coffee maker might be the issue.
I was looking at the Zamp systems, like this:
http://www.amazon.com/Zamp-Solar-40P-Portable-Charge/dp/B00K1LBR1E
[quote source="/post/18669/thread" timestamp="1455383953" author="@catmanriff"]agreed the coffee maker might be the issue.
I was looking at the Zamp systems, like this:
http://www.amazon.com/Zamp-Solar-40P-Portable-Charge/dp/B00K1LBR1E[/quote][font size="3"]That would work, but it's very expensive for a 40W panel. You're paying a lot for the folding aluminum stand etc. A simple home built stand of wood or PVC would be cheaper. Even the fancy 8A PWM controller is overkill since the max current for a 40W panel would be 2.3 Amps. [/font]
True. I think you can later add a panel to that controller.
[quote source="/post/18672/thread" timestamp="1455386477" author="@catmanriff"]True. I think you can later add a panel to that controller. [/quote][font size="3"]Certainly, or two more. [/font]
thanks for the info! i forgot i have a smaller panel with usb ports for my electronics. i don't need the 12v coffee maker and have a percolate for the stove. i have a heater buddy with propane. the light/fan combo is the one they threw in with the camper and also have a battery operated fan light combo. i have an older roll up panel but i can't remember the wattage. it's 2'x4'. i hope to get out for a couple of 1-2 night trips before my big Moab trip in April to test things out.
[font size="3"]Sounds like you're good to go so why ain't you gone yet? 8-)
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From my own experience, we never camp in places where there is any sun, period. The trailer is always shaded. In most of the USFS, SP and NP sites you would have to put your solar panel 50 feet away from your trailer and even then you wouldn't get more than several hours of sun.
We have a similar usage pattern as the OP, excluding the coffee pot, which I agree isn't a candidate for solar. We use about 15 amp hours each day. So our 70 amp hour group 27 battery can last two days or more and stay within the recommended 50% discharge level for best life.
So, given that sun is not available all day and maybe just for a few hours, I would pick a 100 watt system. With full sun all day long a 100 watt panel will put out 25-40 AHs. But figuring that shading will limit you to about half of that, then 12-20 AH of daily output should pretty well keep up.
Here is a page of 100 watt panels in the low $100 range: http://www.amazon.com/s/ref=nb_sb_ss_c_0_10?url=search-alias%3Daps&field-keywords=100+watt+solar+panel&sprefix=100+watt+s%2Caps%2C179
Also add a solar controller like this one: http://www.amazon.com/Morningstar-SK-12-SunKeeper-Charge-Controller/dp/B007NYZ5VU/ref=sr_1_8?ie=UTF8&qid=1455394472&sr=8-8&keywords=morningstar+pwm+charge+controller
The controller is totally waterproof so you can mount it near your battery outside. Wire the output of the panel to the controller by clipping off the MC4 connectors and splicing 14/12/10 gauge wire depending on the distance. Use 10 gauge for 50', the smaller gauges for shorter lengths. Then wire the output of the controller to your battery terminals with at least 14 gauge.
I have such a system on my boat. It cost about $200 and will recharge my batteries within a couple of days in full sun. I have two GC batteries with 220 AHs of capacity.
David
I have a 8.5x22 and often camp in cooler weather and the heater works a lot at night, plus all the interior lights, etc... We would run through one battery easily. So when I replaced the one I added 2 more. I also added a 235 watt panel on the roof with a 12 volt charge controller by GoPower to charge the batteries. It works great with sun of course, but I live in wonderful NM and we get plenty of that. In good sun it will push 9 amps and fully charge batteries in a couple of hours and I'll even switch the fridge over to DC just because I can. When I run the generator in the day I flip the beaker switch so the generator isn't charging batteries as well and that helps the 3500 watt generator run the AC with less of a load. I've considered adding another panel so I can run the fridge during the day on DC and still maintain batteries at 100% for night usage. I haven't installed an inverter yet just due to the initial cost, but I plan to sometime this year.
777:
Some observations and comments about how you use solar power and your generator:
1. When you run the fridge on DC it runs at less cooling output than AC or LPG. It is ok to keep stuff cool, but will struggle if you put something warm in the fridge. Also it draws lots of DC current and will run your batteries down faster. Propane is cheap and it takes very little to run the fridge, and a whole lot less than the equivalent gasoline to run your generator.
2. Your 3,500 watt generator should be able to run the A/C as well as the converter just fine. The A/C draws about 1,500 watts and the converter draws about 600 watts, so the total is well below the generator's capacity.
3. 9 amps DC from a 235 watt panel is low for full sun during the middle of the day. Should be about 15 amps. Look at your wiring size and distances. I would use 14 gauge from the panel to the controller to keep the voltage drop reasonable, maybe 12 gauge if it is more than 20 feet away. But the wire size from the controller to the battery is critical. Since the controller is typically putting out about 14V when you are charging at 15 amps, if you use 14 gauge and the controller is ten feet away from your batteries, the voltage drop is 0.8 volts. That means that the controller thinks it is putting out 14 volts which is what the battery needs to charge it quickly, but due to the voltage drop the battery is really seeing 13.2 volts. That won't do much charging and may be the reason your amperage is low. I would use at least 10 gauge for the controller to battery run which will keep the voltage drop down to 0.3 volts and even bigger if it is more than 10' from the controller to the battery.
David
Thanks a bunch! I need to reroute and do some redesign of the whole front storage bays and will run appropriate sized wire. The distance from panel to controller is only about 10 feet and uses the same gage wire that is on the panel. Again thanks for your input!
[font size="3"]Ditto everything David said. At 12V every tenth of a volt is critical. For example, 20 feet (round trip) of 12AWG at 10 Amps produces a 0.32 volt drop. The run from controller to battery should be 10 minimum, preferably 8AWG.
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Makes me feel good that this retired chemical engineer can garner words of support from a (retired) electrical engineer on an electrical subject.
But seriously, I have lived with this stuff on a boat where unless you have a genset (and marine gensets are $10,000+) you have to carefully manage your DC usage and production. And since propane refrigeration won't work on a sailboat (needs to be kept level to work) the DC requirement is much higher since it has to cover refrigeration. Some boats have several hundred watts of solar panels and several hundred or more amp hours of battery capacity to make it all work out.
I installed my first solar panels on my boat about 15 years ago and every boat since has had solar panels, some with enough capacity to fully cover my DC needs (400 watts) and others to just keep the batteries topped up. (100 watts).
RV DC management is exactly the same as boating use with the exception that boats use 5-10 times more amp hours to provide for refrigeration. Another difference is that RVers call their AC battery charger a converter for some reason. Always made me suspicious that they weren't real three stage chargers, but I read the specs on the one in my CL and it says that it is.
David
777:
I just reread your post and looked up Go Power solar charge controllers. Their solar controllers are all PWM (pulse width modulation) that work with nominal 12V panels. If you have a single 235 watt panel, then it is almost certainly a nominal 24V panel.
The Go Power PWM controller (if that is what it is) is wasting about half of your solar panel's output. You need a MPPT (maximum power point tracking) controller that will convert the 24+V input to the 12+V output that your batteries need.
That is why your amperage is so low if you really do have a PWM controller.
David
How do I check the voltage from the panel, to insure it's the 24v
A simple test is to disconnect your panel from the controller. Then measure the voltage from the panel with nothing connected but your voltmeter while it is pointing towards the sun. If it is a nominal 24V panel, the voltage will be 30+, maybe as high as 40V, the so called Voc (open circuit voltage). If it is a nominal 12V panel, the voltage will be 15+, maybe as high as 20V.
I have never seen a nominal 12V panel at a wattage of 200 or more. The largest 12V panel I have seen is 150 watts.
David
Sounds good, I'm sure it's 24v. Bummed I wasted money on the wrong charge controller. Any brand recommendations for MPPT controller?
[font size="3"]Until David wakes up and has his coffee I'll make a suggestion ;) . My choice would be the Morningstar Sun Saver MPPT
[a href="http://www.morningstarcorp.com/wp-content/uploads/2014/02/SSMPPT_ENG10_1111.pdf"]http://www.morningstarcorp.com/wp-content/uploads/2014/02/SSMPPT_ENG10_1111.pdf[/a]
Although it's rated at 200W max it will handle your panel without damage and the times when you would actually get 235W from your panel are rare. It's available from Amazon and Northern Arizona wind and Solar. Designed in the USA, manufactured in Tiawan (not PRC) and warranted 5 years!
That said I'll yield to David's hands on experience if he has additional suggestions.
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Well, I am up, awake and on my second cup of coffee and agree that the Morningstar controller noted above should work fine. It is listed for $228 on Amazon: http://www.amazon.com/Morningstar-Sunsaver-TrackStar-Charge-Controller/dp/B006H9VPL6/ref=sr_1_1?ie=UTF8&qid=1455719327&sr=8-1&keywords=morningstar+sunsaver+mppt
I have used Morningstar PWM controllers in several applications and they always worked fine. Can't say the same for Chinese made controllers. Well in reality the Morningstar one is probably made in China but it is engineered and QC managed from the US.
FWIW here is what they say about power and current specs: Input power can exceed Nominal Maximum Operating Power, but controller will limit and provide its rated continuous maximum output current into batteries. This will not harm the controller (reminder: do not exceed Voc).
Interestingly that means that it will limit output power to 15 amps if you hook it up to more wattage. The chances of that ever happening with your 235 watt panel are slim in any case as Charlie noted but it is nice that the controller won't be harmed if it somehow happens.
Your Voc should be fine, but you probably should measure it as I described above to make sure. It is very unlikely but they do make nominal 48V panels where the Voc should be above 75. But if you had one of those, you wouldn't even make 9 amps when connected to a PWM controller and it would probably toast the controller.
David
Quote from: @david" timestamp="1455720340" source="/post/18775/threadWell, I am up, awake and on my second cup of coffee and agree that the Morningstar controller noted above should work fine.
Can't say the same for Chinese made controllers. Well in reality the Morningstar one is probably made in China but it is engineered and QC managed from the US.
David
[font size="3"]Good morning. Morningstar is mfg'd in Taiwan, not mainland China. I've had plenty of bad experience with Chinese junk; not so with Taiwan. Chinese products are usually warranted for 5 minutes or 5 miles, whichever occurs first. :( [/font]
Thank you so much Gentlemen. I will start by checking voltage and then by changing the gage of wire from Controller to Batteries. And then change the controller as funds are available.
[quote source="/post/18741/thread" timestamp="1455640042" author="@david"]777:
2. Your 3,500 watt generator should be able to run the A/C as well as the converter just fine. The A/C draws about 1,500 watts and the converter draws about 600 watts, so the total is well below the generator's capacity.
[/quote]This is not quite true. Any compressor can draw up to double it's wattage rating on it's initial start up spike. So a 1500w A/C unit can pull 3000w every time it starts. This can stall the generation or can cause damage to the A/C unit. It is always best to make sure to add this in when figuring generator size.
As for solar I use to have the 45 watt system from Harbor Freight. It was on sale for 99.00. Also added a charge controle for another 20 bucks. This setup wile it worked great was very heavy and a pain to cart around. I now have a Zamp 40 watt briefcase pannel with the built in controler. The convince is well worth the extra cost. Even more so when using it for a small 6.0.
As for your coffee pot. 5 dollars at your local junk store can get you a perkulator that will solve the need to use any electricity for a great cup of coffee.
[quote source="/post/18814/thread" timestamp="1455863266" author="@gawin"][quote source="/post/18741/thread" timestamp="1455640042" author="@david"]777:
2. Your 3,500 watt generator should be able to run the A/C as well as the converter just fine. The A/C draws about 1,500 watts and the converter draws about 600 watts, so the total is well below the generator's capacity.
[/quote]This is not quite true. Any compressor can draw up to double it's wattage rating on it's initial start up spike. So a 1500w A/C unit can pull 3000w every time it starts...[/quote]
If you had your converter switched off when you start the A/C the 3,500w generator should start a 1,500w A/C without issue. Then switch on the convertor to have both running on the generator. I realize some people haven't installed their converters with a switch -- but they should.
I believe its been mentioned around the forum before (in fact I think David may have said this at one time) but there are ways to deal with the AC unit without going overboard on the size of the genset. For example a softstart capacitor will remove the large draw which allows you to use the smaller generator. An example would be this: http://amzn.to/21dwXYm
I advise anyone wanting to do this to do their own research so they fully understand what is going on. Capacitors carry a huge amount of juice and can be dangerous if not handled correctly.
-Sean
Yes anytime dealing with caps you have to remember they hold a charge even when they are no longer connected to power. You have to treat them as always hot.
I really tried to understand this thread but most of it made my head spin.
We have a 6.0 trailer with A/C. My dream was to use solar panels to run the A/C. I have learned that is not going to happen.
On black Friday I got excited and bought this without going any research --> http://www.amazon.com/Watt-Solar-Battery-Charging-Kit/dp/B001RJOP5Y?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00
In the reviews people were saying that it did everything they needed and someone said they used it for their A/C. The numbers didn't mean anything to me so I bought it thinking I was getting a very powerful solar panel. It now sounds like I was very wrong.
During the day we want to run these things:
- Fully charge 2 cell phones, once daily
- This breakfast station to make coffee and breakfast --> http://www.amazon.com/Nostalgia-BSET300RETRORED-Powerful-Breakfast-Station/dp/B00LS7VOCC/ref=sr_1_1?ie=UTF8&qid=1460412089&sr=8-1&keywords=nostalgia+breakfast+station
During the night we want to fun these thing:
- The light that comes with the livin lite trailer (for about 3-4 hours)
- a small portable dvd player
Do I have what I need for that?
When I asked the RV repair shop they said that I should install a 2nd battery and then connect the solar panel so that it charges both. Would that really help?
Another person suggested I install an inverter.
Can you educate this clueless gal?
Thanks
The breakfast station is going to require an inverter at a minimum. I did a very quick look and someone suggested it takes 1500w. That's a significant size for an inverter. If it were me I'd look at other options for your coffee and breakfast.
If you do drop the breakfast cook station then that solar panel is enough. That assumes good sun. That panel should give something like 1 to 1.5 amps per hour in good sun. This will recharge phones and run lights for a good amount of time. It may not fully recharge the battery in one day so if these are constant draws the. You'll want to get more power, but these things are never constant. So unless you are living off grid, or going for weeks on end, you should be fine
Well darn. I guess we could do without the breakfast cook station when we don't have hookups. We only go for 1 - 2 nights any way because we work Mon - Friday.
Everything else can be run on batteries or propane. We even have AA battery phone rechargers. I'm not sure why we would even need solar panels.
[quote source="/post/20465/thread" timestamp="1460412454" author="@sbgirl96"]
Can you educate this clueless gal?
[/quote]The solar panel you have might only be able to keep up with your cell phone charging. Your battery will get lower and lower each day if you try to use much more than that.
It is like a bank account.
The battery is your savings. It only has so much to start with and has a limitation on how quickly you can withdraw from it.
The solar panel is your income. If you are making a set amount of money per hour but your hours available to work vary then your daily take home will vary based on it. The size of the panel is your hourly wage. Your hours available to work are sunny hours in the day.
The devices are your expenditures. You may choose to go all out on a fine dinner, drinks and a movie one day while not eating at all for the next few days or pace yourself for the duration of the week until payday. The devices bleed your savings bank based on how much spending you do. "Cooking Breakfast" can vary in time and will bleed the bank in varying amounts.
It's about budgeting expenditures based on income for a duration your bank account will allow.
Trying to run the electric cook set with what you have now would be like laying your entire savings on the wheel in Vegas with no chance to win. The only benefit would be to watch the wheel spin. As a matter of fact your battery (bank account) probably isn't even big enough to sit at that table to begin with.
Try to lean on propane more or go to a developed campsite and use the 110V plugs. A generator can do. Much more solar and battery could do it.
You would definitely need an inverter too.....that would be compared to currency conversion in money talk.
[quote source="/post/20469/thread" author="@sbgirl96" timestamp="1460417390"]Well darn. I guess we could do without the breakfast cook station when we don't have hookups. We only go for 1 - 2 nights any way because we work Mon - Friday.
Everything else can be run on batteries or propane. We even have AA battery phone rechargers. I'm not sure why we would even need solar panels.
[/quote][span style="font-size:13.3333px;"]Even the smallest solar panel can keep up with the needs of a propane stove, and in any weather <g>.
[/span]Bring a charged USB mini-charger or three and that takes care of your cell phones.
Yeah, you don't need a solar panel.
If you are going to add a permanently wired solar panel to your roof, go with a 100 watt panel and use a PWM controller. Going smaller doesn't save much.
If you just want to keep batteries topped up with no amperage use, then you can hook up a 10-20 watt panel and you really don't even need a controller. Amazon has such a panel for $30-40 or with a controller for $60.
David
What I really wanted was to get a cheap solar panel and run the A/C whenever I wanted. Ha! Ok lesson learned.
At least I only spent $55 on this solar panel. Maybe I should put table legs on it and sell it as art. ;-)
[quote source="/post/20471/thread" timestamp="1460417908" author="@pinstriper"][quote timestamp="1460417390" author="@sbgirl96" source="/post/20469/thread"]Well darn. I guess we could do without the breakfast cook station when we don't have hookups. We only go for 1 - 2 nights any way because we work Mon - Friday.
Everything else can be run on batteries or propane. We even have AA battery phone rechargers. I'm not sure why we would even need solar panels.
[/quote][span style="font-size:13.33px;"]Even the smallest solar panel can keep up with the needs of a propane stove, and in any weather <g>.
[/span]Bring a charged USB mini-charger or three and that takes care of your cell phones.
Yeah, you don't need a solar panel.
[/quote][p]
[/p][p]I love the analogy! Thanks that really helped.
[/p]
Quote from: @david" timestamp="1460417939" source="/post/20472/threadIf you are going to add a permanently wired solar panel to your roof, go with a 100 watt panel and use a PWM controller. Going smaller doesn't save much.
If you just want to keep batteries topped up with no amperage use, then you can hook up a 10-20 watt panel and you really don't even need a controller. Amazon has such a panel for $30-40 or with a controller for $60.
David
[p]David,[/p][p]
[/p][p]Will this one that we bought do the trick for just topping off the battery? [a href="http://www.amazon.com/Watt-Solar-Battery-Charging-Kit/dp/B001RJOP5Y?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00"]http://www.amazon.com/Watt-Solar-Battery-Charging-Kit/dp/B001RJOP5Y?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00[/a][/p][p]
[/p][p]
[/p]
Yes, that system should work fine for keeping the batteries topped up when you are not camping.
And if you only camp for a couple of days at a time, you will never run down your batteries enough to worry about it, given your usage.
David
Other than AC. That's just unpossible on batteries that you can carry.
Well, AC powered by solar isn't impossible. It just may not be feasible for a quicksilver. These guys (while inexperienced it seems) put a lot of money into their solar system and they are able to maintain their batteries while running only on solar: https://www.youtube.com/watch?v=B0rZY5uotKI
Not practical for most of us, but still possible if you have the time, money, and desire.
[font size="3"]Hmmmmm. 960 watt solar + 3kW inverter + 700 AH Li battery - QS6 = - infinity. Hmmmmmmm ;)
[/font]
Everything is possible with enough lithium. Trust me.
I was going to go lithium batteries this time around. Then found out you need to heat them in the winter in order to charge them. Plus, there is a lithium shortage from all the cottage industry designer drug makers extracting from Sudafed.
Thats why I qualified my statement. The batteries to do this all day would be what....6 ? 10?
And 3500watts of solar is a shit-ton of panels.
Money aside, can you imagine trying to get all those panels and equipment onto a QS6? lol
No, I cannot. And I have a powerful imagination.
I'm picturing something like this
(http://vignette1.wikia.nocookie.net/disney/images/5/5c/F97a636b49945ddc2ba12d07f41380f8.jpg/revision/latest?cb=20140417061501)
Those solar chargers listed, at 21 or fewer watts, are more suited to charge up your laptop, tablet, phone or similar than to keep your trailer battery charged. If you are going to install a solar panel, go for at least 100 watts. 100 watts is the sweet spot in 12V solar panels. You can buy one for $110 including shipping if you are a member of Amazon Prime. If you need more watts than that, and I suspect you won't, then buy two.
Here is some math and rules of thumb:
Most single trailer batteries have about 70 amp hours of capacity and most of us only use 15-20 amp hours daily. A 100 watt solar panel laying flat in full sun will make 25-35 amp hours each day. So the 100 watt panel will keep your battery fully charged if you get full sun at least every other day and you use the typical amp hours each day. More watts also compensates for afternoon shading, because many campsites are in the shade at least part of the day. In that case a 100 watt panel might only produce 10-15 amp hours each day, but even that will extend your batteries from lasting 2 days to almost a week, as long as the sun shines.
Here is a simple system that costs about $200-250. All it takes is a little wiring to put it together. The controller is waterproof, so you could mount it to the back of your solar panel if the distance to the batteries is short- say 10' or on the side of the battery box if it is longer. The panels are Chinese made, like most of them and I have never seen any complaints about Chinese solar panels. They make a gazillion of them. The controller is American, well at least American design and QA management and are from a major supplier of solar controllers- Morningstar. I have a system like this on my boat and it has kept the batteries charged nicely while on a mooring away from shorepower.
Here are some simple instructions for building a solar system and mounting the controller on the outside of your battery box:
Mount the controller near the outside of your battery box using a couple of #10 or larger screws and nuts. Then get as many feet of MC4 cable as you need to go from the panel to the controller. For 25' of cable, you will need to use a pair of MC4 10 gauge cables like these- https://www.amazon.com/Solar-Panel-Extension-Cable-Connectors/dp/B00KDNQQRK/ref=sr_1_8?ie=UTF8&qid=1480515257&sr=8-8&keywords=mc4+cable. You can use 12 gauge if the distance is less. 100' is probably the practical maximum as there would be too much voltage drop otherwise.
Then wire a short MC4 pigtail cable like this to the input of your solar controller- https://www.amazon.com/Grape-Solar-GS-MC4-CC-6-Inch-Conversion/dp/B00MS8AKRU/ref=sr_1_7?ie=UTF8&qid=1480515257&sr=8-7&keywords=mc4+cable. You can use automotive type clamp connectors or butt crimp connectors. Finally wire the output of the controller to the battery lugs using a couple of short lengths of stranded 12 gauge cable. Use an inline fuse in the positive wire to protect it like this one- https://www.amazon.com/AutoEC-Inline-Waterproof-Fuse-Holder/dp/B013JG8GIY/ref=sr_1_5?ie=UTF8&qid=1480516741&sr=8-5&keywords=inline+fuse
When you get to your campground, place the solar panel in a sunny spot. Run the MC4 extension cable from the panel and plug it into the MC4 pigtails on the controller. Make sure that you maintain polarity when you hook up the extensions. Then you are in business. When you are ready to go home, disconnect the extension cable and flip up the pigtail into the battery box to protect it while traveling.
Solar panel- https://www.amazon.com/HQST-Watt-Polycrystalline-Solar-Panel/dp/B018BOK9WU/ref=sr_1_1?ie=UTF8&qid=1479928915&sr=8-1-spons&keywords=100+watt+solar+panel&psc=1
Waterproof controller- https://www.amazon.com/Morningstar-SK-12-SunKeeper-Charge-Controller/dp/B007NYZ5VU/ref=sr_1_3?ie=UTF8&qid=1479929271&sr=8-3&keywords=morningstar+pwm+charge+controller
David
I have not gone the solar panel route for recharging as I have not found myself out long enough off grid to require it. I always make sure the battery is fully charged before heading out and use solar rechargeable lights in the camper instead of the 12 volt supplied lights and use a Goal zero Yeti 150 for charging phones, tablets, cameras etc. In this way I can stretch out the battery life for quite a while. We also can recharge phones, the Yeti and other devices when we are in the car heading off someplace- that extends the battery life in the camper for a long long time.