(hope this is right section) Brought home TT last month and now have basics taken care of and RV is road ready. Now starting to think about bigger long term projects.One project is, we would like to get some solar. Which I know nothing about. I suspect the first step is figuring out a starting place for this project. So I'm assuming that finding how much we actually need might be a good starting spot. Is there any meter or way to measure to figure out what we need? I'm thinking, if we know how much we use, we could determine how big or small of solar project would be. Thinking in my mind about some type of elec meter that we see how much we use in a week. Or maybe better yet; how did you figure out how much solar you needed?Anybody care to pass on any good links or info on RV solar?Thanks

get something like this Power Amp/Watt meterput it inline with the battery measure how much power you useper day AKA 24hrs and per nightto be truly effective for long camping periodsthe solar has to twice what you use between sundown and sunriseit has to replace what you used at night..while recharging the batteries and powering what power you use during the dayhowever.. IF you merely want to keep from killing the batteries aka extend your stay and then recharge them while the TT is in storageyou can use a smaller solar systemyes figuring out Both how much you use and what you want from the solar system.most people do NOT need "the full blown ..double power"matching your nightly use.. is enough for most people

How much you need and how much you can use are two different things. There is a spread sheet that you can fill out as long as you know what each device uses and for how long. You can base it on how much battery you have.You can use the rig and see what the daily drop in voltage on the battery is.Then again you may look at your roof after figuring it all out and see you need X amount of solar but only have room for half that.Honestly with the prices of solar being so low, I would cover the roof in panel and put as much battery as you can down below, go forth and be solarful. You can't expand the systems so if you run out of power, learn to conserve.I had a pretty good idea of how much power we needed but I also knew we were very conservative too. We took one panel with us as a portable to see if it would be enough or if solar would work at all. Within a day we went from being conservative to looking for ways to use the excess power. We now have more panel and went from 30-40 ah to 200 ah a day with all the comforts of home including air conditioning and we don't take a generator.

Just keep in mind that a typical 120WATT SOLAR PANEL will only produce around 5 AMPs DC current when in the high sun.You will need alot of panels to just run yout system off the solar panels to run many things in your trailer.What you want to do is install enough batteries to run all of the 120VAC items you want to run from a INVERTER running off the batteries and 12VDC items direct connected to the battery bank.Then you want to use enough solar panels to re-charge these battery banks back up to their 90% charge state in the time period the solar panels are in high sun. Just be aware to re-charge a 12VDC deep cycle battery from its 50% charge state to its 90% charge state in a three hour smart mode run time will take 14.4VDC with the capacity of 17-20AMPs DC Current. You will have to get a very large solar panel system to produce this amount of power during the high sun time frame.Then you have to worry about what happens if it is cloudy or raining. You will not get enough sun then to charge your batteries. Now you have to have a generator set to do the charging.It takes planning and knowing how it all works...For our life style of camping off the power grid I am looking into installing two 120WATT panels on the front of my POPUP trailer roof and a larger 200 watt or bigger solar panel on the rear of my popup trailer roof. This will only give me around 20AMPS of DC current so I may have to run my generator for the first hour of re-charging to get my battery charge draw below the initial high current charge requirement and then allow the solar panels to finish off my battery charge for the rest of the high sun day. The 20AMPS total Solar output would only re-charge one of my four batteries in a three hour run. These are the type of things I will have to plan for... All of this depends on what you want to do with your trailer when camping off the power grid.food for thought hereRoy Ken

You can't depend on the sun.In full sun like AZ, a couple 3 hundred watts goes a long way. Start small, 2-3 hundred watts, keeping the plan so you can easily add a couple hundred more if needed (wanted)I am not a "more battery" fan ! They are very heavy, and are like horses eating hay.

In conserve mode, we use about 20a per day. That is what I would start with. A number.

How to measure how much solar we need? | Good Sam Community

92 Replies

JiminDenver
Explorer II
Nov 20, 2014
How much you need and how much you can use are two different things.

There is a spread sheet that you can fill out as long as you know what each device uses and for how long.

You can base it on how much battery you have.

You can use the rig and see what the daily drop in voltage on the battery is.

Then again you may look at your roof after figuring it all out and see you need X amount of solar but only have room for half that.

Honestly with the prices of solar being so low, I would cover the roof in panel and put as much battery as you can down below, go forth and be solarful. You can't expand the systems so if you run out of power, learn to conserve.

I had a pretty good idea of how much power we needed but I also knew we were very conservative too. We took one panel with us as a portable to see if it would be enough or if solar would work at all. Within a day we went from being conservative to looking for ways to use the excess power. We now have more panel and went from 30-40 ah to 200 ah a day with all the comforts of home including air conditioning and we don't take a generator.
MrWizard
Moderator
Nov 20, 2014
get something like this Power Amp/Watt meter

put it inline with the battery measure how much power you use

per day AKA 24hrs and per night

to be truly effective for long camping periods
the solar has to twice what you use between sundown and sunrise
it has to replace what you used at night..while recharging the batteries and powering what power you use during the day

however.. IF you merely want to keep from killing the batteries aka extend your stay and then recharge them while the TT is in storage
you can use a smaller solar system

yes figuring out Both how much you use and what you want from the solar system.
most people do NOT need "the full blown ..double power"

matching your nightly use.. is enough for most people

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How to measure how much solar we need?

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