# solar set up for cabin/camp



## wittey (Nov 17, 2003)

Hey all, I have Property in Northern AZ that I get to just a few weekends a year. I have a small cabin120 sq ft. 
I have 2 40W(edited from 20w, see below post) solar panels I would like to use for lights and music (I am thinking a car stereo system.
I need to know what all i need for this? What battery, charge controller, size of wire? I would only be using it when i am there, I would store it in another shed when not in use. Thank you very much for your input.


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## MichaelK! (Oct 22, 2010)

Too small! On a good day in full sun right at noon, expect to get a little over 2 amps per hour. Less than half if the sun's in a different part of the sky and if the latitudial angle isn't adjusted too.

Basicly, that's a trickle charge to maintain a battery that's already charged, like your ATV or parked car.


Let's say you have a lamp with three CFL bulbs. Mine has two 14W and one 7W. All together they consume about 5 amps per hour of use. Call that 5AH. My TV is UL listed at 90W, but what I see in the real world is that it consumes about 5 amps per hour. Your stereo is probubly about the same. Lets say I go to my cabin, spend the night, and watch TV for 2 hours. I leave the lights on for a total of 4 hours. I would consume about 30 AmpHr of power total. That's (5Ahx2hr)+(5Ahx4hr)=(10)+(20)=30 AmpHr.

Now, getting back to your system. Let's assume you align your panels perfectly and you get 2.5 amps at noon. You'll likely be getting only ~ a TOTAL of 12 AH over the course of the whole day. That is NOT going to cover the amount of power you consume.

Even if you only use the battery(s) once per week, and charge the rest of the time, it's still not likely to replace what you want to consume.

For a workable starter system, I'd recommend getting at least two 100W panels, a 20-30 amp charge controller, like Sunforce, and two Trojian T105 6 volt batteries (wired in series). Link that with a 400watt inverter, and you'll be able to power what you are talking about. Wire it all with at least 12 gauge copper wire.

Good luck!


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## wittey (Nov 17, 2003)

I made a mistake, when I tested them a couple years they were 19.3 volts and 2.3 amps. what I wrote down faded and I thought the volts was Watts. so they are actually 40 watts each.


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## wy_white_wolf (Oct 14, 2004)

wittey said:


> ... I would only be using it when i am there, I would store it in another shed when not in use. Thank you very much for your input.


That kind of creates a problem with going solar. I have a small setup on my weekend cabin in Montana. But we leave it setup when we're gone so the batteries will be charged up when we get there. If you store everything away the batteries will self discharge. If you can't leave it setup you may as well forget about solar and just take the batteries home and put them on a charger.

My little system is 1 51 watt panel, 2 12V Deka batteries for 232 Ah, 6A PWM charge controller, and a 150W inverter. After a weekend there I figure it takes about 10 days to fully recharge the battery. All we us it for is music (cheap boom box) and lights.

Wiring will depend on the amps of your load and distance. There's lots of wiring calculators out there that will help with that.

WWW


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## wittey (Nov 17, 2003)

Thanks Wolf, That pretty much how I would like my system. What are they actually Deka batteries you are using. I wasn't sure if I should convert it to AC or just keep it DC.


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## wy_white_wolf (Oct 14, 2004)

wittey said:


> Thanks Wolf, That pretty much how I would like my system. What are they actually Deka batteries you are using. I wasn't sure if I should convert it to AC or just keep it DC.


Deka is the brand. I bought the largest RV/Marine battery that they made at the time. They weren't cheap but not as back as trojan golf cart batteries (T-105) in my area.

WWW


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## buenijo (Jun 14, 2012)

Check out Renogy products. A good place to search is systems normally used on RV's as you're considering similar energy usage. A good forum is at cheaprvliving.com.


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## JeepHammer (May 12, 2015)

What I would do if it were me...

I would mount the panels where they can get sun when you aren't there.
I would get panels with built in charge controllers, 
Or I would get a charge controller.

I would use AGM or Gel Cells instead of wet (flooded) batteries,
Since there won't be anyone there to maintain them most of the time.
AGM/Gel cells don't need water/routine maintinance.

I would use MP3 or IPod and speakers for music,
MUCH less current required, and they are made in 12 volt DC so no inverter required.

I would use LED lighting, again, very low consumption current required,
And already produced for 12 vehicle systems.

I can't stress this enough,
With micro systems, LOW CONSUMPTION is the name of the game...

China is dumping 150 watt panels just dirt cheap on the world market,
And if you can get them cheap enough, buying several isn't going to bust the budget...
Just food for thought.

AGM or Gel Cells are NOT cheap, but with no one to regularly maintain the batteries,
There is no way around that...
More or larger panels will power everything just fine during sun hours, without draining the batteries,
And that will reduce the need for more battery power...
Panels live a good long time with no maintinance,
While the same can't be said of batteries.
Smart money goes in panels. Add extra batteries as you need them.


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