# Solar panels



## Seadawg (Nov 2, 2015)

I own a 2015 Nash travel trailer that has a 20 watt solar panel installed by the manufacturer on the roof. I want to add portable solar panels to connect to each of the two 12 volt batteries, so that I can go longer without using my Oman propane generator. What size is needed? Any product recommendations?


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## Dub (Dec 27, 2015)

I have the same setup on my camper. The 20 watt panel is just enough to keep the batteries up while the camper isn't being used. I added an additional 80 watts worth of panels which give me an extra 6 amps for the batteries in full sun. That's a nice bump and does bring the batteries up to a full charge by the end of the day as long as there's not a lot of power usage throughout the day. As far as a perfect size for you, that depends on how much the camper is being used and what accessories as well. I am thinking the optimal size for me would be an extra 200 watts (~15 amps). probably 100W x2 panels. Since the built-in charge controller will NOT handle that much additional power, it will either need to be replaced or an additional one added. I took the easy route and added a polarized connector to one of my batteries so that when I get to my destination I can plug in a charge controller with my 80w panel. 
Just a couple of tips:
Mount your charge controller close to the batteries and use good quality fairly heavy copper wire. The shorter the wire run and larger wire the better as this will cause less of a voltage drop. That being said, you don't need to go overly large on the wire. I used 10ga which is plenty.
This also allows for longer wire runs with a smaller gauge wire out to your panels. Since your panels will produce a voltage that is normally many volts higher than your battery voltage, a little bit of a drop is insignificant.
When I get another panel, I will be using 2 separate 30ft. wires from my charge controller out to the panels. This will allow me to move the panels around separately rather than having them tied together electrically at the panel with minimum movement. It's been my experience that the panels need to be moved around quite often if you're in a timbered area in order to keep getting full sun.
One last note. Although pwm charge controllers are cheaper and they do work well, I would recommend a mppt controller if you can afford it, do a lot of camping, rely heavily on your panels and are in an area where the sun may be limited. I use a pwm on my camper and mppt on my house and love it. I will be upgrading to mppt on the camper soon. I would recommend doing your research before selecting a controller and panels to see what will be right for you. You may want to calculate the amount of power being used by the camper and accessories and then determine how much power it takes to bring the batteries back to full charge. Unless your camping in the desert, you can probably only count on 5-6 hours a day of full sun on your panels.


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## LEN (Dec 28, 2015)

100 watts per battery is a good rule of thumb. You can run the two charging systems in parallel, just need to as above find an EZ way to hookup the new panels with it's own controller to the batteries.
Look on EBAY there are a lot of good 200 watt systems that are at a reasonable price, or Amazon is another source to compare price. Make sure to get a 30amp controller, it's over kill for now but solar gets to be a habit of more is better and this leaves room to go to 400 watts if later you wish.

LEN


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## PickleMax (Feb 29, 2016)

LdEN said:


> 100 watts per battery is a good rule of thumb. You can run the two charging systems in parallel, just need to as above find an EZ way to hookup the new panels with it's own controller to the batteries.
> Look on EBAY there are a lot of good 200 watt systems that are at a reasonable price, or Amazon is another source to compare price. Make sure to get a 30amp controller, it's over kill for now but solar gets to be a habit of more is better and this leaves room to go to 400 watts if later you wish.
> 
> LEN



Do you think that you can run all the electrical appliances in an RV just with the power from solar panels. I'm thinking about putting one on the roof for our next trip.


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## Dub (Feb 29, 2016)

PickleMax said:


> Do you think that you can run all the electrical appliances in an RV just with the power from solar panels. I'm thinking about putting one on the roof for our next trip.


It really depends on what you have for appliances and how many watts your panels are. What are you thinking about powering? Do you have an inverter in your RV? The main goal of solar is to keep you batteries charged (or help) while you use small things like lights, stereo, TV, phone chargers, water pump, etc.. Just the 12v stuff. You wont be able to run things like the microwave or air conditioner. You can run some small AC powered things if you have an inverter, but leave the power hungry devices to a generator.


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