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Hook
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Solar panels in a suitcase
I was by the big bash in Quartzite, AZ this year in late January. There was a product that intrigued me, with an application for my truck camper
setup.
Basically, two firms were marketing two solar panels that fit into an aluminum suitcase. Inside the suitcase was a mounted charge controller. On the
outside of the suitcase were "legs" that were adjustable that allowed one to angle the panels at the sun.
The idea here is that you can manually move the panels (mounted inside the case) in relation to the sun. Very portable. Take it with any rig you own.
It also came with about 50 feet of cabling with large clips for attaching to your batterie(s).
Any opinions on this type of setup? I THINK that they were marketing two 70w panels in this for around 500 bucks. The suitcase was somewhere around 2
feet by 3 feet. The panels were NOT thin film type, that I remember.
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wessongroup
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Thanks Hook .... solar on my mind.. "again"... with the price of propane moving one way all the time...
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Diver
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Not sure of the cost ??
We have an 80 watt Kyocera panel that my wife made a padded slip-on bag for.
I glued a small charge controller to the back and have it connected to 35' of 12 ga extension chord so we can move it around the camper for best
sunlight.
My battery has the other end of the extension chord wired on and hanging out of it's box, ready for power.
I'm sure you can do this with any size panel.
But the suitcase idea does sound pretty guchi !
.
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comitan
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Hook
Both combined were probably 70W, and the loss in 50ft of wire
Strive For The Ideal, But Deal With What\'s Real.
Every day is a new day, better than the day before.(from some song)
Lord, Keep your arm around my shoulder and your hand over my mouth.
“The sincere pursuit of truth requires you to entertain the possibility that everything you believe to be true may in fact be false”
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wessongroup
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Good point..
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bajamedic
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In my previous career in the emergency services, there was a fold up solar system from Daniels Electronics for our portable repeaters. They came as
a 60 watt, 12 VDC system, folded up to 6”X10” and unfolded to make a 4’X6’ panel. They came in a hard plastic case, complete with rope, mallet and
connectors, everything needed to deploy quickly. You might check the system at
http://www.danelec.com/products/hardware/solar.asp
I do not recall the cost of this system, but I do remember that quality and dependability was primary. JH
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Hook
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Quote: | Originally posted by bajamedic
In my previous career in the emergency services, there was a fold up solar system from Daniels Electronics for our portable repeaters. They came as
a 60 watt, 12 VDC system, folded up to 6”X10” and unfolded to make a 4’X6’ panel. They came in a hard plastic case, complete with rope, mallet and
connectors, everything needed to deploy quickly. You might check the system at
http://www.danelec.com/products/hardware/solar.asp
I do not recall the cost of this system, but I do remember that quality and dependability was primary. JH |
I've looked at those foldable panels and they seem to be extremely pricey for the current generated. I think they are mostly sold for military use and
are mil spec.
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Hook
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Quote: | Originally posted by comitan
Hook
Both combined were probably 70W, and the loss in 50ft of wire |
So, what would you have to reduce the run to in order to get full power out of both?
Most houses having panel on the roof dont have their batteries in the attic. I imagine that runs of at least 25 feet are common. They just accept a
30-50% loss of current?
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mtgoat666
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Quote: | Originally posted by Hook
Quote: | Originally posted by comitan
Hook
Both combined were probably 70W, and the loss in 50ft of wire |
So, what would you have to reduce the run to in order to get full power out of both?
Most houses having panel on the roof dont have their batteries in the attic. I imagine that runs of at least 25 feet are common. They just accept a
30-50% loss of current? |
several of the vendors have wire size calculators to help you figure transmission loss.
but 30 to 50 percent loss is unacceptably bad design, don't buy from a vendor that says 30% is acceptable. 3% is max you should lose.
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larryC
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Quote: | Originally posted by Hook
Quote: | Originally posted by comitan
Hook
Both combined were probably 70W, and the loss in 50ft of wire |
So, what would you have to reduce the run to in order to get full power out of both?
Most houses having panel on the roof dont have their batteries in the attic. I imagine that runs of at least 25 feet are common. They just accept a
30-50% loss of current? |
To get more current you would need to increase the wire size, and as mtgoat666 says there are lots of wire size charts out there. I would guess the
amperage of a 70 watt panel is around 6 amps at most, probably a little less, at 12v. Keeping the wire runs to less than 10' with #10 wire would keep
your losses to acceptable levels.
MPPT charge controllers now a days can accept voltages upwards of 150 volts. So by wiring your panels in series you raise your panel voltage and are
able to carry the current from all the panels using smaller wires and longer distances. Thats how some houses have panels on the roof and batteries on
the floor.
HTH
Larry
[Edited on 2-10-2012 by larryC]
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Hook
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10 feet away from a side mounted battery in a camper may keep me in the rig's shadow at times. I generally travel from 1August to early October, so
the sun has begun to make it's swing south. And I am usually above the southern border of Utah.
Plus, if my camp has an ill placed tree, 10 feet wont get me around it.
The 30-50% loss is based on Comitan's comment that TWO 70watt panels with 50 feet of cable might only produce the output of one panel. At least thats
the way I read it.
Guess I better find a wire size calculator............
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wessongroup
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You guys here .. have such a great deal of knowledge on so many things ... thanks to all...
Save time, save money, save work and a few others ... ask here..
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Fernweh
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Here's a link with a few electrical calculators:
http://www.mikeholt.com/technical.php?id=technicalvoltagedro...
The feared voltage loss is not only important to a solar installation, but for many (sub)standard electrical house wiring's in Mexico.
Too long of a wire run with a small AWG wire can damage electrical equipment, especially electrical motors.
My friend in El Centenario supplies his house via a 340' long line from the meter pole with only #6 AWG = very bad!
Karl
[Edited on 2-10-2012 by Fernweh]
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Diver
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If you connect a cable as I mentioned above with a short chord with plug ends, you can always insert an additional chord if you need to move the panel
further. You might loose some power but it's better than having the panel sitting in the shade. Our 80 watt panel on it's 35' chord still has plenty
of power to charge our 2 batteries from 1/3 to full any mostly sunny day.
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Bob and Susan
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actually vendors havent a clue what size is needed to move small voltage
the grids they supply are WAY wrong
the thickest stranded cable is what you want
to move small voltage
this is why 115v is used in houses
it can run along way on smaller wire
also when it gets hot outside the current will drop even farther
answer...BIG wire to the controler from solar panels and dont use plugs
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comitan
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And big wire from the controller to battery, also the shortest distance.
Strive For The Ideal, But Deal With What\'s Real.
Every day is a new day, better than the day before.(from some song)
Lord, Keep your arm around my shoulder and your hand over my mouth.
“The sincere pursuit of truth requires you to entertain the possibility that everything you believe to be true may in fact be false”
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Bob and Susan
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and..BIG wires from battery to battery
NOT car battery cables...they are too small
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Diver
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Were I wiring a house or permanent installation, I would definitely follow all of the guidelines that Bob and Comi are relating.
But since Hook asked about a mobile system....
For a mobile system designed for occasional use with the necessity to relocate or re-aim the panel and to set it up in many varying locations, it may
not be possible to conveniently accomplish the utmost in wire sizing and connections.
Our system is wired for convenience as the ideal in wire sizes and lengths would make our style of use impossible. We may not get the most amps out of
our panel but we get plenty to satisfy our demands. I would think to design your small mobile system with a large enough panel(s) to supply your needs
given the anticipated losses.
In our case, our panel is spec'd to put out 5.2 amps and we actually get 4.8 amps on a sunny day with our chord. One 80 amp panel runs lights, water
pump, radio, computer, etc. If we winter camp or for multiple cloudy days, we add a second panel. We use 2 Bi-Mart deep cell batteries that we
purchase for $55 each every 5 years and they are connected with standard battery cables.
My ideal RV set-up would include huge wiring to batteries and permanently-mounted panels with adjustable sun-seeking mounts plus detachable panels for
times when you have to park in shade and a small windmill along with 4 big expensive 6V batteries.
Having not collected my Lotto winnings yet, I do what I can.
.
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bajalou
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Quote: | Originally posted by Hook
Quote: | Originally posted by comitan
Hook
So, what would you have to reduce the run to in order to get full power out of both?
Most houses having panel on the roof dont have their batteries in the attic. I imagine that runs of at least 25 feet are common. They just accept a
30-50% loss of current? |
They run larger wire, some up to 00 welding lead to reduce this loss.
I'm running 000 for the ground and 4 for positive for each of the 2 sections of my array. |
No Bad Days
\"Never argue with an idiot. People watching may not be able to tell the difference\"
\"The trouble with doing nothing is - how do I know when I\'m done?\"
Nomad Baja Interactive map
And in the San Felipe area - check out Valle Chico area
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msteve1014
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I have 2, 85 watt panels bolted together with a hing so they make a kind of suitcase. Inside is the controller, legs, and wiring when we travel. Open
it up and clip the wires to a pigtail on the camper and your done. 20 feet of #10 s.o. cord has always been plenty to set the panels in a good spot. I
made this to power an ARB freezer, and the rest of the camper. The freezer is the big power draw. Fans and lights do not use much.
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