# RV solar



## Huge29 (Sep 17, 2007)

Im about to buy a camp trailer and I am thinking of adding a solar panel like this one 



It looks like a fairly simple install, just run the cable down the fridge vent, pull the fridge and down underneath, pull them back up in the storage compartment where I would mount the controller and on to my two 6-volt batteries. Looks like I just need some stainless screws to install the brackets directly into the decking and some proflex rv sealant around the screws. Anything I should know? 
I have dealt with these very little, but a trailer my dad had with these the batteries were unstoppable; do you do anything differently when not in use? 
We are looking at building a house and looking into solar for that too; I am intrigued, but not overly impressed with the breakeven period being so long, but doable. Any input would be greatly appreciated.


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## DallanC (Jan 13, 2009)

Two things with solar panels, they work best when facing the sun directly... if its flat on your RV you wont get the specified wattage. Secondly, make darn sure that the controller will cut off voltage to the battery when they are full charge, otherwise it will fry your batteries. Also if you have batteries that are not maintance free, you will have to check the water more frequently.

You might want to make a stand for the panel and some quick connect's to the battery and just pull it out and set it up facing the sun when setting up camp rather than roof mount it.

-DallanC


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## Critter (Mar 20, 2010)

My brother in law has some on the top of his slide in camper and they work great in keeping his two golf cart batteries charged. His only problem is when he parks directly in the shade or it snows. If it snows we just get the broom out and brush them off. 

I believe that a lot of the newer trailers have solar panels as a option already installed anymore and they all are mounted flat on top of the trailer from what I have seen.


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## gdog (Sep 13, 2007)

DallanC said:


> You might want to make a stand for the panel and some quick connect's to the battery and just pull it out and set it up facing the sun when setting up camp rather than roof mount it.
> 
> -DallanC


This is what I am going to try this summer. Need to decide on what solar package to buy yet....


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## hemionus (Aug 23, 2009)

We did it on my cousins trailer using the harbor freight kit. Much cheaper and has worked awesome.


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## 2full (Apr 8, 2010)

I ran one on top of my trailer for several years. Didn't have a controller set up.
It worked great, never had any problems at all, and did not have to use the generator at all after I set it up. Never fried a battery....just used a simple one that attached to the battery.
When I sold the trailer I gave the unit to a friend of mine, and he is still using it.
I will be putting my solar system in my cabin this summer.


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## gdog (Sep 13, 2007)

This one from Habor Freight gets good review and its cheap. May not be the best, but if it keeps my trailer batteries charged...game on for the price.

http://www.harborfreight.com/45-watt-solar-panel-kit-68751-8527.html


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## Huge29 (Sep 17, 2007)

gdog said:


> This one from Habor Freight gets good review and its cheap. May not be the best, but if it keeps my trailer batteries charged...game on for the price.
> 
> http://www.harborfreight.com/45-watt-solar-panel-kit-68751-8527.html


Not a terrible idea; my brother has that and the one panel already cracked and is more money than this one on Amazon with only half of the power....I like it for when it is not being used too in that it is keeping it all charged up too... The HF one just does not keep his charged up worth squat, not certain that it isnt an issue with his setup, that is possible.


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## richardjb (Apr 1, 2008)

I've had a120 W put on my camper in 2010, with the 6 Volt batteries. I've camped for over a month on the mountain with out a problem. Laying flat on top of camper works fine.


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## DallanC (Jan 13, 2009)

How much juice do you guys use when out camping? I guess solar would work if all you are doing is a few lights in the evening and maybe running a waterpump from time to time. 

I still carry a Generator or two (when I need AC, dual Honda 2000's linked) and always end up using it.


-DallanC


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## Critter (Mar 20, 2010)

Unless you have a good size bank of batteries I doubt that you could get a solar set up to keep up with running a AC unit or a lot of electrical, that stuff takes a lot of watts to run. 

It always amazes me when I go camping and find those that have to sit inside their air conditioned camper trailer with the TV on all day and the only time that they come out is once the sun goes down. They then complain that they didn't find anything to do while they were out camping. I have 3 or 4 of these type of campers in my group of friends and then there are the ones that complain about the dirt when they go camping.


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## richardjb (Apr 1, 2008)

I would run a couple lights and TV at night.


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## Huge29 (Sep 17, 2007)

Critter said:


> Unless you have a good size bank of batteries I doubt that you could get a solar set up to keep up with running a AC unit or a lot of electrical, that stuff takes a lot of watts to run.
> 
> It always amazes me when I go camping and find those that have to sit inside their air conditioned camper trailer with the TV on all day and the only time that they come out is once the sun goes down. They then complain that they didn't find anything to do while they were out camping. I have 3 or 4 of these type of campers in my group of friends and then there are the ones that complain about the dirt when they go camping.


Definitely no AC with solar; I have found that the newer ones can run on 2,000 watt generator at the minimum with little else running. I also dont get the AC, unless you are at Powell just trying to sleep at night.
That dirt...its just so dirty!


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## highcountryfever (Aug 24, 2009)

for your "optimal" power output from your panel they need to face south. You also need to be very aware of shade. If ANY part of an individual cell is shaded your power is severely cut. plug in your multimeter and stick your hand over the panel and you will see what I mean. 

Solar for charging batteries and running a few lights works great. If you are wanting to power a TV you will need to buy an inverter. To run sensitive electronics like LCD tv's you need a pure sine-wave inverter. Most won't work with the modified sine-wave inverters. (I wouldn't even try it with a modified if you value your TV). 

Last thing, The reason Solar is not a good idea for your AC is the surge loading required for startup. On average you can plan on 3-5 times normal operating loading for your surge requirements. 

Hope that helps. I am in no way an expert on all things solar, but I do have a little bit of formal training and experience


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## gdog (Sep 13, 2007)

Here's another that has good reviews. Looking at this for recharging rv batteries while out camping.


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## klbzdad (Apr 3, 2012)

I installed this on my trailer and will almost never have to run my generator again. 3x 100 Watt panels in parallel and plenty of amps to charge two deep cycle 6v batteries (will add two next year to the bank for a total of 4). Don't buy the one from Amazon unless your trailer is a positive ground unit. Most trailers are negative ground (to the frame/chassis).

I have not added a fourth panel yet (next year) or a true sine wave converter yet (converts DC to AC). I'm happy to provide links and advice, just PM me. Spend the extra money to get an MPPT controller/charger. Better for your batteries and deep charges them.


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## gdog (Sep 13, 2007)

Those are the same panels I'm looking at now. Renogy has a specific setup for RV use, with the negative ground as you mentioned.

http://www.renogy-store.com/Renogy-100W-12V-Mono-solar-RV-Kit-p/kit-rv100d-vs.htm


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## bowgy (Oct 10, 2007)

ebay has them for under $200. I would look up a local solar dealer and see if they have some used stuff from someone who upgraded. I would also check their prices before I bought on line.

Buying the individual parts may be cheaper than a kit and you could custom it for your needs.


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## Huge29 (Sep 17, 2007)

A few questions on this:
1-Why would the negative/positive ground matter? Isn't the panel just mounted into the decking to where ground is only established through the actual cables?
2-How did you route your cables down from the roof? I have seen them going down the fridge vent, which seems like the cleanest method.
3-What all are you running there to need so many panels, just your SFW neon sign on the mountain?
4-Why the pics with the cardboard showing? Is that during install or do you cover them when not in use?
5-If you don't mind, what have your costs been roughly?
Thanks for the info!


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## klbzdad (Apr 3, 2012)

If you look at used solar, beware. Check to see if there is ANY browning on the panels and do not buy used poly panels as they are unreliable and damage is hard to see. I did buy the Renogy kit after negotiating a price with them minus parts I wouldn't use like the MC4 connectors and 12 awg cables as I wanted everything tidy and simple so I purchased 3-1 MC4 connectors 1 male 1 female, bought 40 feet of 10 awg solar cable with male and female MC4 ends, a 30 amp inline fuse and a push pull kill switch. I still have the positive ground PWM controller but that is the beauty of an MPPT, four stage charging and PWM output to your batteries means your batteries last longer, are protected from overcharging, and your solar panels are protected as well. It took me three years to piece together the setup I posted along with educating myself on how to do it without burning down my trailer. Best purchase ever and I'm into it around $800.00 or so but will save twice that not running up the hill to run my generator just to keep my fridge on all season and keeping batteries charged. Plus, NO NOISE! Not even a hum. 

Being flat mounted on the roof only matters if its winter. The rating of the panels are estimated based on perfect conditions and location. Parallel keeps my volts and watts consistent with very little drop in amps. I can't wait to get the sine converter installed and mothball the generator for good. 


FYI, I can run my shore line into a 4k inverter connected directly to my battery and run my air conditioner. I wouldn't recommend it because of the start up surge but I had to see if it would work.


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## klbzdad (Apr 3, 2012)

Huge29 said:


> A few questions on this:
> 1-Why would the negative/positive ground matter? Isn't the panel just mounted into the decking to where ground is only established through the actual cables?
> 
> Your system is set up either to ground through a positive connection through out your trailer's wiring or negative earth ground to the chassis. To cross them is crossing polarity and will damage the charge controller at minimum and could be very bad for the rest of the trailer and solar panels. A good MPPT charge controller fixes that issue as most are negative ground or able to differentiate and adjust. They are NOT cheap although mine is an expensive one wrapped in a cheap shell.
> ...


You could get away with a single panel system, just make sure you match up your system amps with the right size cable and controller and double check polarity (usually only fifth wheels will be positive ground). Again, worth every damned penny!!!!!


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## bowgy (Oct 10, 2007)

One of the reasons I recommended looking at used is because I am a solar dealer, I don't do RV stuff mostly communications sites and have helped a few friends put solar in their cabins.

I use used ones in my RV, they were older ones from a 12v to a 24v upgrade, I also gave a friend of mine a couple used panels and a used regulator/charger and he has been using it for years.

For mine I like to park my RV in shaded areas if possible so I have 2 panels mounted on an aluminum frame that I set just inside the door for storage and have some long wires on it, then I can lean it up against a tree or rock or stand it on it's own with a south facing exposure at about a 55 degree angle. I also have a chain with a lock if I'm in an area where I think it might be taken.

It's a little more hassle but it's worth it to me to be able to park it in the shade.

This is one of the sites I built, for an example.


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## Huge29 (Sep 17, 2007)

Thanks for teh info Guys! So, klbz, you run your fridge on 110 with the inverter, then? That is amazing that those would run your AC.


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## klbzdad (Apr 3, 2012)

No, the fridge runs off 12v side. It uses the electricity to control the thermostat on the heating element. The heating element is heated by LP gas. Here's a basic diagram of how it works:










As far as the AC running off an inverter, I was told I took too big of a chance of burning the entire system out because of the surge. It was only running for a couple seconds and I unplugged it. I wouldn't recommend it without installing a properly rated sine wave converter in order to get solid juice to the AC unit.


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## DallanC (Jan 13, 2009)

klbzdad said:


> No, the fridge runs off 12v side. It uses the electricity to control the thermostat on the heating element. The heating element is heated by LP gas. Here's a basic diagram of how it works:


This tech is soo cool. I cant believe our 12v propane fridge / freezer will freeze anything.



> As far as the AC running off an inverter, I was told I took too big of a chance of burning the entire system out because of the surge.  It was only running for a couple seconds and I unplugged it. I wouldn't recommend it without installing a properly rated sine wave converter in order to get solid juice to the AC unit.


Yea dont do it unless you have a ton of batteries or you will burn stuff up. Even with dual Honda 2000's in parallel for the start up, it has a hard time running it with one gen turned off @ 2000ish watts at high altitude. I keep hoping like the refrigerators, someone will invent a AC unit that requires a fraction of the juice.

Oh and once we took a camping trip to Lake Mead when I was young... to this day I still clearly remember it being 95 degrees inside the stupid camper at 10pm and trying to sleep. Swore right hten and there I'd never own a trailer without AC. Even if I never use it, I'll never own anything with out one. As is, we still use the AC several times each year, and the fan quite often all by itself.

-DallanC


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## klbzdad (Apr 3, 2012)

I'm gonna do one of these with an old Igloo cooler and a 12v fan.

https://snapguide.com/guides/make-an-air-conditioner-in-5-mins-for-20/


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## bowgy (Oct 10, 2007)

klbzdad said:


> I'm gonna do one of these with an old Igloo cooler and a 12v fan.
> 
> https://snapguide.com/guides/make-an-air-conditioner-in-5-mins-for-20/


You could probably get one or two low current 12volt fans from some old electronic equipment and run it on a solar panel or 2.


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## klbzdad (Apr 3, 2012)

bowgy said:


> You could probably get one or two low current 12volt fans from some old electronic equipment and run it on a solar panel or 2.


The charger controller has a 2.5 amp 12v load connection if I wanted to punch holes and run the wire. The simpler ya keep it, the simpler it is to repair or replace. Now, I have to reinforce the fresh water tanks and their sagging utters.


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