Portable Solar Panel

[BirdMan]

I finished my portable solar panel yesterday and have been testing the system.  Below is what I created including pictures, products, and prices.  This is going to be a great improvement over carrying more batteries or having to fire up a generator in the woods.  

So why make it portable?  Simple, we usually try to park/camp in the shade and if you had a solar panel on top of your pop-up we would be very limited on how much sun you get directly on the solar panel for recharging.  I wanted the system to be water-resistant or as water-proof as possible without costing me hundreds ($$) more.

First I looked at my needs, i.e. how many Amp Hours (A/h) do I use in a normal 24hr day when camping.  I first determined I would use just shy of 30A/h per day.  After my LED upgrade (details on this later) it dropped to 21A/h per day.  To ensure I oversized my system I took this number and multiplied it by 125% and came up with a system that at a minimum can produce 30A per day back into my battery.

This number is VERY low for most campers from my experience.  We generally only dry camp so we are always in conservation mode.  We only use Lights for a few hours per evening, the water pump, and furnace fan at night.

The easiest and cheapest way to significantly lower the A/hr's used was to replace my two overhead fluorescent lamps with LED Lamps.  My overhead fluorescent lamps were drawing about 1.25A per light.  The replacement LED Lamps I purchased draw 190mA per assembly and are much brighter.  This upgrade does not require changing out the light receptacles, JUST THE BULBS and a piece of double sided thin carpet tape to stick it to the top of your existing recepticle.  You can get LED lamps in just about any type of connector and in 2000 Coleman used miniature wedge type connectors on the bulbs.  As many of you know, the fluorescent lamps you have in your pop-up look kind of yellow with on.  This is because a standard fluorescent buld has a dominant wavelengh around 3000 Correlated Color Temperature (CCT) measured in Kelvin (nm/K) while the LED Lamps I installed are around 7000 CCT and are very white.  

Here are the products I purchased and prices:

80W Sharp NE-80EJE Multi-Crystal Solar Panel, $362.00 NEW including shipping off eBay.

Unirac Rack product# 990012 for a stable platform on the ground with adjustable angles, $66.30

Charge Controller made by Morningstar Corp called there SunKeeper-12 model# SK-12, $89.00

Two L6-20P Plugs made by Pass & Seymour, $32.50 for both

Two L6-20C Caps made by Pass & Seymour, $30.44 for both

One 15A fuse for hot side of battery/solar panel. Bought from Napa Auto model# 782-3002, $8.49

Two Tray Cable Grips for J-Box on back of Solar Panel model# COLO-00518, $9.00 for both

LED Bulbs purchased from

//www.superbrightleds.com, model# T10-PCB-CWHP9, $43.90 for both [/list]

Shortest 10ga Extension Cord (rated SJTW) was 50' at HomeDepot for $52.00 (get the brightest color possible!!!)

Tube of 100% Silicon, $5.00

Misc Clips and Connectors for Solar Panel Terminal Block and Battery Posts, $5.00

The total for everything purchased was $703.63.

Some things to know about solar panels used to charge batteries; you want to ensure you have no more then a 2% loss from the solar panel to the battery.  From the battery to your appliances you can have a much higher loss without any problems, but it is crucial that you stay below a 2% loss to your battery.   The length of your extension cord depends on two things; how many amps will be on the circuit and the guage of the wire used.  Using 10ga wire I could have a maximum one-way distance of 23' between the Solar Panel and the battery.  I made two 18" pigtails, one on the battery side and one on the Solar Panel side, which left me with a 20' 10ga Extension Cord.  Using smaller wire means your distance is less.  

Another thing to consider is safety; batteries are always hot and solar panels are always hot (while in the sun).  In order to ensure no one (like myself) gets shocked while things are unplugged I decided to use Twist-lock Caps (L6-20C) on both pigtails that come off the battery and the solar panel.  For those not sure what I mean here, a Receptacle is what you use in a wall mount to plug things into while a Cap is the female side of an extension cord.  By setting things up this way I don't have to worry about accidentally touching the Plug to ground and shorting my battery or shocking myself and the same holds true on the Solar Panel side of things.

My 20' Extension Cord has a Twist-lock male plug (L6-20P) on each end.  This way I only have to worry about shocking myself while hooking & unhooking the extension cord to the system.  You want the brightest color extension cord possible so people don't trip over it while you have it installed.  I used twist-lock plugs & caps to ensure it stays connected much better.

There has been much talk about if you should or should not use a Charge Controller with your Solar System.  I did a lot of research on this and talked to many people in the solar business and the consensus was you DEFINITELY want to install a charge controller.  The new Charge Controller products on the market, like the one I purchased made by Morningstar Corp, does not have ANY disadvantages.  All the newer style Charge Controllers send out a high frequency charge back to the battery(s) while monitoring the battery charge and automatically going into a float charge state once the battery gets to a 100% charge.  Also, when the voltage get to low from lack of sunlight the Charge Controller dis-engages from the battery so the Solar Panel does not draw down the battery at night.

Since the Sharp Solar Panels come with a J-box on the back and inside is a terminal block to connect your wires I found a really nice product to ensure the J-Box stays water-proof called a Tray Cable Grip.  You will see them in the picture of the J-Box on the back of the solar panel.  This product makes the connection to the J-Box water-proof ad grips the cable very tightly to ensure they don't get pulled out of the box or any unwanted stress on the terminal block.  I was not able to use the rubber grommet inside when pulling all three 10ga wires through so I had to remove it.  Though I did fill the inside of the grommet with silicon to ensure no water gets in the J-Box.  

Another safety feature I incorporated was to ground my solar panel frame.  You will see the green wire grounded to the solar panel frame on one end and to the frame of the trailer on the other end.  This is more of a safety factor for lightning strikes from what I am told, but since the smallest number of conductors in any 10ga extension cord I could find was two (including another one for ground) I thought I would put it to use.

The final product works great, is portable, provides more A/h then I use in a day by at least 125%, the extension cord is very flexible, and is very easy to store and setup.

Below are a few picture of the Completed Battery Box Connection, Front of Solar Panel in use, Back of Solar Panel in use, Solar Panel Frame Installed, Pigtail Caps (same type of connection on Ext. Cord except using Plugs, J-Box connections, and Charge Controller hooked to J-Box.

If you have found this site/link then you know by now that battery voltage is one thing you have to monitor when dry camping.  One way to do this is every couple hours go out with your volt meter, take the battery cover off, and check the voltage.  Not a problem in good weather or during the day, but how about when it is raining, past midnight, or god forbid snowing?  Install your own push-button volt meter by checking out this link //www.arveeclub.com/showthread.php?t=64034.

[ForestCreature]

Nice Job. We have our solar portable too, it's the best way to have it.

[Jim K in PA]

Excellent project and write up, Birdman.  Thanks for sharing.  Any data on the output?  I was planning to go with a 110W for mine, but if I can use an 80w, that would save some $$ and space.

[JimS]

Good job on your setup.  It looks like it will do the job nicely.  I did a similar system last year ( http://www.arveeclub.com/showthread.php?t=63953, and http://www.arveeclub.com/showthread.php?t=64509, for my two write-ups ) and it worked very well.  You will definately like being able to camp as long as you want without worrying about the batteries!  One small suggestion: I noticed that you have about 2" of bracket above the top of the panel.  I think it would be best to move the panel to the top holes to get it higher off the ground.  This will help reduce rain splatter from the ground along the bottom of the panel.  Enjoy your diligent research and hard work and let us know how well it works after your first trip!

[BirdMan]

Jim, you are correct on moving the bracket.  This is set-up this way for the moment because when I hooked everything up I noticed my charge controller was pointing off the bottom of the J-Box.  It has an LED on it that you want to look at occationally to see what state it is in (sleep/night, full charging, float charge, short, ...).  I flipped part of the bracket for testing, which is how you see it in the pictures, and here soon I will move the solar panel up on the bracket.

This bracket will also be mounted to two boards or alumimun that I can then use huricane stakes, probably only one, to screw into the ground so it wont flip in the wind while I am out fishing, hiking, or just playing around.  By using one stake I can turn the solar panel during the day to face the sun without having to take out and pound/screw both back in multiple times per day.

[JimS]

This bracket will also be mounted to two boards or alumimun that I can then use huricane stakes, probably only one, to screw into the ground so it wont flip in the wind while I am out fishing, hiking, or just playing around.  By using one stake I can turn the solar panel during the day to face the sun without having to take out and pound/screw both back in multiple times per day.

This is a really good idea. Also, it will help discourage those who have sticky fingers!  I am still trying to work out an effective lock system for the panel.  Just can't seem to come up with something that is quick and effective.  I'll keep thinking on it.

[BirdMan]

Initial testing was a big success!  Yesterday evening at around 7pm I turned the furnace on set at 65 degrees.  With the thermostat being about 12" off the floor the temperature at head level must of been about 75 degrees.  The furnace was on until 6am this morning.  About every 20-30 minutes the furnace fan would kick on for 5-10 minutes.  This test was done in my driveway, 6400' elevation, low last night was 41 degrees F.

Battery at 7pm before turning on the furnace was at 100% (12.6+ V).  Voltage of battery at 6:30am was 11.99V which equates to about 48% charge left.  The battery sat for 30 minutes without any load, or solar panel connected, before voltage measurement.  

JimK, you asked about output.  My research has showed that the spec's the reputable manufactures (Sharp, Kyoceras, BP, GE, Sunsei, ... ) publish are very accurate.  I was also told this by several reputable large Solar Installation Companies.  For my 80W Sharp Solar Panel it will put out 4.67A and 17.1V.  

Within two hours this morning the solar panel charge controller was already in a float charge state.  This does not mean my battery is at full charge as it is more like a "smart" battery charger where it jacks the voltage high at first then reduces it as the battery gets close to fully charged then keeps it at a float charge state.

I also wanted to mention that there are three available Solar Cell Technologies on the market today.  They are monocrystalline, polycrystalline, and amorphous.  You won't mind much monocrystalline product on the market as this technology takes a special kind of silicon sand ore and is in great shortage.  I could go into great detail on each of these, but safer and shorter to say "do your homework" before investing in any of these technologies.

[austinado16]

Man that's nice!  And an excellent write up too.  I wish Dave would "Sticky" yours and JimS's write ups so that folks could find them fast and do some easy one-stop shopping in the future.

Wish I had the coin to build a little system like these.

One quick question:

We don't have a water pump, and it's not often that we need to use the furnace......and I haven't done the LED conversion to my overhead twin 1156 bulb lights (2 fixtures with 2 bulbs each).  Could I get buy with a smaller panel? 50watts?  Seems like your 80watt panel topped the battery off (or was close to topping the battery off) pretty quickly.....so would a smaller panel do the job, but maybe take a few more hours to fully charge?

[wavery]

Man that's nice!  And an excellent write up too.  I wish Dave would "Sticky" yours and JimS's write ups so that folks could find them fast and do some easy one-stop shopping in the future.

Wish I had the coin to build a little system like these.

One quick question:

We don't have a water pump, and it's not often that we need to use the furnace......and I haven't done the LED conversion to my overhead twin 1156 bulb lights (2 fixtures with 2 bulbs each).  Could I get buy with a smaller panel? 50watts?  Seems like your 80watt panel topped the battery off (or was close to topping the battery off) pretty quickly.....so would a smaller panel do the job, but maybe take a few more hours to fully charge?

It's just math...

A 50w panel will give you about 4A per hour in full sunlight. Just think of it as a 4A battery charger that gets weaker as the sun gets lower.

There really would be little to no need for any voltage controller with the smaller panels. Just check the battery voltage twice a day and and unhook the panel in the unlikely event that you ever see 14.8 volts at the battery.

When using solar panels, it's real important to keep an eye on your battery water.

[JimS]

austinado16,
You could probably get by with a 50 W panel if it received full sun for most of the day.  It seems as if your draw is fairly low.  Also, for this, I tend to agree with wavery as to the need for a controller.  Open circuit voltage on a 50 W panel is around 17V at 3-4 amps.  As he said, you would have to keep watch on the battery for overcharging and water level.  The setup would act as a single phase charger with bulk charge only.  RV Solar Electric offers a standard size panel kit that is 50W.
Jim

[BirdMan]

austinado16:

Those 1156 bulbs draw 2.1A per bulb.  I think you said you have four and if you have them all on you are drawing 8.4A for every hour they are running.  That's a very large draw for a small amount of light you get.  Based off of what you have said to everyone on your usage you should be able to get along with a 50W panel.

Look at it this way, even if you can't keep up with your overall daily current draw you will definitely be able to stay out dry camping several more days then without any solar panel.  You can also add another 12V solar panel later in parallel with your first one.

The LED lamps I purchased draw 190mA (.19A) per lamp.  When you replace all four you will only be drawing 760mA (.76A).  The total load of all for LED's is less then one of your existing bulbs.  In other words if you had only one of your 1056 bulbs plugged in and lit for an hour you would draw 2.1A from your battery.  With all four of the LED Lamps running you could let them run for 2.76 hours using the same current draw.

Not to mention you will not believe how bright white the LED's I am recommending are.  

The LED lamps I purchased you can see and buy at //www.superbrightleds.com/other_bulbs.htm.  Scroll down until you see a small panel with nine LED's on it, part number T10-PCB-CWHP9.  Click on "Buy Now".  For your replacement the third bulb down is "1156-PCB-WHP9 White LED Lamp" MAKE SURE YOUR SELECT "Cool White - 7000K".

Now all you need is four small pieces of 1/4" wide double sided carpet tape to stick them to the top of your existing lamp receptacles and plug them in.

[austinado16]

JimS, Wavery, and Birdman, thanks for the response.

Looked at those LED's......why wouldn't I go with the 32LED version instead of the 9LED version?  When I do change to LED's, I'll do the porch light too, because it's also an 1156 bulb.  Doing this upgrade has been on my list since our first outings last year.

I'm using a Optima Yellow Top AGM battery that I picked up on Craigslist locally for $60.  We've had good luck with it so far.

I don't have the money to throw at a solar system right now, but I still want to learn about them, and look at what's available, what I need, and what prices are like.  Who knows, might trip over someone selling some used panels and just "have to" pull the trigger.

[ForestCreature]

austinado16, we get along with 45 watts. Our usage is minimal, biggest power hog is the furnace for us and that's not used except early spring and fall with it off during the day , till we go in at night. Temp set at 60 while we sleep.

It's kept up just fine, we have one of those ICP triple panel systems that costco sold, been using it for almost 8 years. Some day we'll get a single lightweight panel to make it easier to move about.

[BirdMan]

Good question!  It's not about the number of LED's on the bulb/panel.  It's about three things: Brightness(lumens), Color(wavelength), and Beam Pattern(degrees).  Another way to quickly determine how much light you will get is pick the LED assembly with the highest current draw, though this tells you nothing about the color you will get from them.

The 36 LED panels //www.superbrightlights sells, product# T10-PCB-W36, has the following specs:
Current Draw=123mA, Lumens=57, Wavelength=9000, Beam Pattern=100

The product I got for myself, T10-PCB-CWHP9, with 9 LED's has the following specs:
Current Draw=190mA, Lumens=120, Wavelength=7000, Beam Pattern=120

Notice that the 9 LED assembly is twice as bright by comparing the number of lumens they put out.  Also has a wider beam pattern.  The higher the wavelength the more the light starts having a blue/purple tint.  A wavelength of 7000 looks very white to me and is also in the range of what is called "cool white".

Hope this helps.

[BirdMan]

Listed above you will see the test results from the first night of camping.  Below is the second night.

Solar Panel was connected during all sunlight hours today.  Disconnected solar panel at 8PM.  At 9PM battery voltage was 12.84V.  NOTE: Anything above 12.6V is considered fully charged.

Set heater thermostat to 60 degrees.  At 6AM the next morning I turned off the heater.  At 6:30am the battery voltage settled to 12.17V.  This represents that there is still 57% of battery power left.

I was really not concerned about the draw of the water pump, thought it is the hightest draw component in the trailer at 4A.  The reason being is we use this during the day for a few seconds at a time with the occational shower and most of the current (if not all depending on the solor output at that moment) will be handled directly from the solar panel and not from the battery.

With the new LED's I don't have to really even consider how much they are used as the current draw is now VERY low.  One old lamp was about 1.2A of draw.  I can now run both LED assemblies for 3.2 hours with the same current draw as using one of the old bulbs for one hour.  Normally we only have one or the other lamp on at a given time anyway.