I just bought a nice pull behind camper and would like to install some solar panels on it to make it more self contained as well as tie the system into my home when it is just parked. I have tried to find a video online or even a diagram explaining how to wire this up, but all i can find is off grid installation information for campers and rv's. I want to be able to plug my camper into shore power and still run the solar set up when that is not available. Additionally, i would like to use the panels as a tie in grid system for my house when i am not on the road. I am not sure if i need to buy a separate inverter and install a switch that will cut the power to the camper when i plug the solar panels into my house outlet to feed my home system. I plan on buying an mppt charge controller and 400 to 500 watts of solar panels. Can i just connect the load to the ac input in on my camper fuse box? i do have a free breaker slot available that i could connect the load to if that will work. If so, can I still plug the camper into shore power while the solar system is running? If i use the free breaker slot, i could just flip the breaker before i plug the camper into shore power if i need to. Additionally, if the breaker slot installation will work, can i use the existing shore plug to feed the power to my house or do i need to cut the feed (basic switch) going to the trailer charge controller from the solar panels, connect them to a second inverter, and then run a new plug from that inverter to plug into my home outlet for tie in use? If i can connect the load to a breaker in the camper fuse box, would i need a separate inverter or could i just run a second load wire with a plug from the charge controller to feed it back to the grid? I realize there is a lot of questions here. depending on how i need to install this system may make some of them irrelevant. However, I would appreciate any advice on this.

RV solar is outfitted for the 12V system.With 400-500W of modules you won't be able to achieve +120V DC when connecting in series to grid tie to a conventional residential controller/inverter.The main design failure is the assumption that solar modules are all capable of producing 120V AC. Typical solar modules output up to 35 V DC (although there are some rarities that output 70V DC).Good reading here: Golden Rules of Solar

I realize the panels will not produce 120v. I was planning on having battery bank in the camper that is large enough to run lights, maybe charge a laptop, run a tv if possible, or a fan for a few days. I did not think about the power feeding back in the lines if there was a power failure if i use it as a tie in system. I was looking at purchasing a cheap 600 watt inverter to connect the solar system to my house outlet. I could put a switch to cut the panels from the camper and install a plug on the side of the camper, which could then send the 18v dc into an inverter and a relay in my garage. I am planning on buying an on/off grid system for my house within the next year, so buying some of the pieces now would not be a big deal. However, the system for my house will be around 5000 watts, so anything i buy now I will need to be able to handle a much larger system down the road. The tie in system could wait until i install the bigger system on my house, but I figured if the panels are working i might as well be using the power that is coming off of them, even if it is a small amount. Where i am located i can easily angle the panels true south with no obstructions. I appreciate the response and thanks for the link.

You will need a charge controller for the off grid end of things. A grid tie inverter (here is what I am looking at) to take the panel output and convert it into 120/240 volt AC - and grid tie it. A simple inverter will blow if its output is attached to a live grid. The last thing you will need is a relay or double pole switch to either connect the panels to the charge controller, or the grid tie inverter. A relay with a 120 volt coil on the output of the inverter will do the job, and as soon as you unplug the panels - switch to off grid mode, plug back in and they switch to grid tie mode. Your onboard converter will keep the batteries charged when grid tied (and be powered off the grid tie inverter during the day), and the charge controller will charge them when off grid.

I forgot to add that i am buying an mppt charge controller for the camper. I thought that was in my first post. Really the important question i need answered is; Can i connect the load off the mppt charge controller directly to an ac breaker in my camper fuse box? I was just looking at cheap "inverters" on ebay for the connection to the house. I realize that you need to convert the dc current to ac. The "inverters" they are selling may actually be converters. they call them "grid tie inverters" in the ads. They state you can connect the panels directly to them and then just plug the "inverter" into a wall socket to feed the power. I did watch a guy who had a bank of 600w "grid tie inverters" in a camper that he had hooked to some kind transfer switch, but it was not automatic and he did not show how the system was connected directly to the fuse box in the camper. I am more concerned about the connection to my camper right now. I dont want to hook the charge controller up wrong and end up burning out part of my electrical system. The relay and double pole switch are both great ideas. I was thinking of having 2 switches, but there is always a possibility of both getting turned to the on position.

Hi I have a grid tie system of 22 220w panels, it can produce in the neighborhood of 700 KW-450 a month from spring through winter here in South Carolina,IF you are going to grid tie I would seriously consider The Enphase micro inverters...one sits behind each panel and can be easily added on too as you grow your system. It will take the DC solar panel and convert it to AC, Thus as your system grows you will not have a large headache as with a central string inverter. You can find my output on the Enphase web site as "Gavin's system" On good days I make about 30 kw The Enphase system is all plug and play. OK, on your camper you will need a charge controller, between your batteries and your panels, it essentially dumps or disconnnets from the battery any excess power....excess power or overcharging is a bad thing on batteries it will make lead acid batteries boil themselves dry and ruin them, much less the hydrogen gas that will need venting. The Lithium batteries will die dead flat from a overcharge, so a charge controller is very important.Another couple of things to consider: A good inverter back to AC.With a standard string inverter, if one row of panels is shaded from an obstruction as the sun moves across the sky, it will knock the whole row of panels out of production, but with a micro inverter only that one panel is affected while the others keep on producing. Another thing is....and I really hate to be a buzz killer here for you is, that unless you really conserve power or live alone or maybe with someone else who is real frugal with power, a few panels..maybe 2-4 wont make hardly a differance in your power bill. The reason I put in my own panels is that my energy costs are high here in the neighborhood of 18-20 cents a kw, its an old Co-op from the 1930's and until recently they had crappy service and didnt give a******about the customer, they acted all smug about reaming the customer each month, but with panel prices falling I thought it would give them a reaming too.... they were oblivous to the panel prices dropping and told me the adventure would be too expensive yada yada yada. Now they are scrambling as more and more folks on the same grid are doing what I just did a few years ago.The threshold of "cheap power" is in the neighborhood of 10 cents a kw I didnt do it to be a hippie or be an over the top "Green Person", it instead just made pure economic sense to do so and the added benefit was beating those jackasses at their own game. All the best! Gavin

solar on/off grid installation | Good Sam Community

dabedwe
Explorer
Jul 09, 2015
JiminDenver wrote:
I have to ask what is the 1000 BTU air conditioner? I use our solar to run a 5000 BTU A/C pulling 450w.

It is a American Comfort ACW100 1,000 BTU Portable Personal Air Conditioner. they actually discontinued them, but mine works great. You can only use it in a very small space, which is probably why they were discontinued. They are perfect for small campers. You still might be able to pick one up if you look around on the internet. My camper is only 14', so I do not need much to cool it down.
westend
Explorer
Jul 07, 2015
I had to look it up, too, Jim----personal space air conditioner
JiminDenver
Explorer II
Jul 07, 2015
I have to ask what is the 1000 BTU air conditioner? I use our solar to run a 5000 BTU A/C pulling 450w.
westend
Explorer
Jul 07, 2015
Yes, as long as you have at least 250 AH of batteries to store the charge.
dabedwe
Explorer
Jul 07, 2015

To really hit on specific advice, share what you have now and how you use your RV.

right now power really is not an issue. the places i have traveled have power hook ups. However, there are some places i want to travel were i will not have an external power source available. With the panel array that i am looking to purchase, I am sure i can get by with 3 or 4 batteries. I do have a 1000 btu portable air conditioner that uses 250 watts. I would not use this often, but i would like to have the option if i find myself in a place with no power hook ups. I might only find myself in this type of scenario once or twice a year and just for 2 or 3 days. I do have a 24" flat screen tv in my camper, but i also have a nice laptop that i can use when if power is an issue. I have limited space on my roof. My camper is only 14' and i have a 8000btu ac, antenna, bathroom fan, and a few other things on the roof. do you think 400 or 500 watts of panels would charge enough batteries to run a 1000 btu 250 watt ac for 6 hours at night? other than the ac, i would only need panels to run lights, a radio, charge a cell phone or laptop, maybe run the tv occasionally, and stay in when the power goes out in my house (i live in the midwest and it happens multiple times a year).
westend
Explorer
Jul 06, 2015
i do have a converter in the camper that converts dc to ac. It is just a standard camper converter system.
A standard RV converter converts AC to DC. 120V-> (nominal) 12V. Progressive Dynamics is a well respected brand name for RV converters. I have one that is still operating well at 44 yrs. old.

To really hit on specific advice, share what you have now and how you use your RV. Calculations of power use is especially helpful.

Typically, the output of the solar controller is fed into the batteries, directly. Since even a modest system is producing 20+ amps at 14V or so, cable dimensions should be on the larger side. I often suggest to upgrade the onboard converter wiring to the battery at the same time solar is installed. For those using solar, some also use a generator and squeezing the most out of generator run time with just a cable replacement makes economic sense.

Here is a list of Forum member solar installations There are many good ideas pictured and explained in the threads.
dabedwe
Explorer
Jul 06, 2015
Gavin60 wrote:
The Enphase system is all plug and play.

I like the idea of the Enphase system. I have read that linked panels can all go down if one gets some shade. I assume you can also run into problems if you have some kind of defect with a panel. I am definitely going to take this into consideration when i purchase home systems. thanks for the info!
dabedwe
Explorer
Jul 06, 2015
I appreciate all the feedback that i have received on this post. When i first decided that i wanted to do a solar system for my camper, i assumed that the mppt charge controller load output was ac. I did not realize that you needed an inverter. from the cheap full systems i have seen, the inverter is left out. I guess these are strictly for off grid installations only. I definitely want some decent equipment. I only asked about hooking the load from the charge controller to an ac breaker due to the fact that i assumed the load was ac. Since the load is dc, i think connecting it to the dc side (fuse box) would be more beneficial now. there is no reason to convert 12v to ac and then back to dc. most of the equipment i have is ac/dc. the air conditioner unit and the microwave are the only thing that runs strictly off ac power. i do have a converter in the camper that converts dc to ac. It is just a standard camper converter system. I have been thinking of replacing the whole unit with something better (if anyone has suggestions for better quality replacement unit let me know). So now that i have been enlightened. Sould i hook to the load off the mppt charge controller to the dc inputs on the fuse box or should i forget that setup completely and just connect the new battery bank that is connected to the mppt charge controller dc output in a series with the original battery that is on the camper? Just connecting the new batteries from the charge controller to the old battery would actually simplify things and may be the best option for me. I now feel like i have been making this installation more complicated than it really needs to be :)
reed_cundiff
Explorer
Jul 05, 2015
We have a LFP battery suite. LFP should not remain at high float for extended periods of time (3.4 V per cell) and keeping an LFP suite on continuous charge from line power will degrade the cells. Chris of Technomadia candidly writes about the problems they had with his in his write-up of 3.5 years of LFP usage.

For this reason our son designed and fabricated our system so that the original 50 amp inlet system is isolated from the battery charging system. The 50 amp system (which we have not used in two years) will only run the AC appliances: hot water, micro-wave, air conditioner. The original OPM converter is only used to supply power from the battery suite via the 508 W Mean Well 48 to 12 V converter. We have tossed the 50 amp cable and its replacement 30 amp cable since we have not used either in two years except to trial the system.

The battery suite can be charged via a 1.5 kW battery charger and a 15 amp (120 V) extension cord. We have used this once when it was 103 at an RV park in Spokane (were visiting relatives and no place to boondock) and we were in the shade and really wanted a/c.

Daughter has about 6 or 7 kW of solar, brother-in-law has around 3.1 kW and son has around 5 or 6 kW of solar.
Reed and Elaine
Crazy_Ray
Explorer
Jul 05, 2015
Roy when are you going to get your Solar? What brand are you looking for? I waited 5 years, bought 1 panel at a time and have ended up with over 500 watts. Love my solar. :B

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