Posts Tagged ‘off grid’

10 Watt panel and Alum case

I spent the last couple days tinkering with the Solar laptop Station.  Yesterday I got to run the laptop with it for a bit.  Those of you that have been following in some of the Tiny House Forums /Blogs know that I have been working on this idea for the last few weeks.  I had picked up some 10 Watt Solar panels during the summer to set up some testing rigs for the I-pod / Computer speaker “stereo”,  and recently picked up a few more parts to make this work.  My original plan had a custom made wood box to house the solar panel / battery etc…I ditched that Idea, It was bit bulky and heavy.  I found some Aluminum briefcases on e-bay that were the right size for my project.  Not only are they lighter and more user friendly they look pretty tech.  I set it up with the basic idea of a 10 watt panel feeding into a 2.2 A/Hr battery. The battery feeds a standard cigarette socket, since most people have many “car” adapters to run things (Cell phone, laptop, portable DVD, etc.) this prototype could supply power for many things other than a laptop.  To aide in monitoring I wired in a few switches that allow me to isolate the solar panel from the battery and the battery from the Solar Panel.  By reading voltage at the auxiliary banana plug ports.  I can easily see how much power is being generated by the panel and what the current state of charge is of the battery. 

The Solar panel has a small channel on the aluminum frame that  fits perfectly into the edge of the case.  A couple of custom mini bungee cords and the panel is held nicely in the case at a great angle collecting sunshine.  Inside the case there is enough room for an additional or a larger battery.  I have some “pick and pluck” foam coming in soon that I will add to the case to secure a spot for the net-book.  The panel will fit into the lid of the case and is held in place by a nylon strap.  It only takes a few seconds to set the panel and attach the bungees.  I will add a Morningstar  Sunguard Charge Controller as soon as I get it in.  The style of SLA (Sealed Lead Acid) battery I’m using prefers a charge voltage of about 14 volts.  The charge controller will ensure this is the case.  This panel can generate over 20 volts in bright sun and even puts out 18 or better just sitting by the window.  If I continued to use these higher charge voltages the batteries would not perform as well.

I”ll do some more testing on charge and discharge rates over the next week or so to test the capacity of the 2.2 AH battery.   The case that is pictured here is the thinnest I got.  I also have two deeper cases that I will be building up as well.  The bigger cases could easily hold the 10 AH battery I got, or one that’s bigger still.  They will also have room for a small inverter to make a complete portable “power station”.  My goal is to have something that is still very portable, yet powerful enough to supply the needs of regular use.  I have seen some “ready made” systems, but they have tiny panels that must take forever to charge with….and some are quite pricey too.  I’m hoping to build these for $300 to $350 for a few select clients / friends.

Here are some links to some  ready made units that I found online, one with some storage capacity (very small compared to my 2.2 ah) and one that just has a panel and cigarette socket.


Innergy Power

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OK I admit it…I’m a bit of a Science Geek. When we first started to plan the cabin we knew we would be off grid, not a surprise really since the nearest utility power is about a mile away. So with an Off Grid system you have a number of options. To keep costs down the #1 rule is to be efficient. The less energy you use, the less energy you need to make. Pretty simple really, since large solar panels can run hundreds of dollar each and then the batteries you need to store that energy, hundreds more.  The least amount you can get away with will keep the cost down.  Our cabin will have a few basics, lights and a few “toys”.   For lighting we chose LED’s.  By far the best in power usage and longevity. To keep things even simpler I decided to stay with the native 12 V DC that the Solar panels produce for the lights.  The “toys” are run via a 1000 Watt modified sine wave inverter.  For music we are using an Ipod, hooked up to a set of computer speakers that are being run off the 12 Volt system.

I looked at some light systems for RV’s and Marine applications but these were mostly incandescent.   A few CFL options were out there but at a price premium.  Style also came into play,  most of the RV lights were darn right ugly,  the cool marine ones were outrageously expensive, $150 to $300 per fixture!

Here is a special marine light that lists for $275. 


I found some manufacturers that made LED’s in a number of voltages, from 12 to 240. I also found a handful of LED GU10 bulbs but all 120 volt. I finally found a supplier who would make some LED’s in 12 volts at a decent price. These had the standard screw base. The lights we wanted to use had a GU10 socket for the normal 50 watt Halogen bulb. I replaced the internal fixture with a ceramic screw fixture.  The 3″ mini can lights run about $16 at Home Depot, 3 bucks for the screw fixture, and less than 10 for the custom 12 volt LED bulbs.  These lights use about 1 watt compared to the 50 for the halogen, they also have a life span of 60,000 hours. The light output is a bit less than the halogen, but this can be compensated by just a couple more fixtures.  I purchased a dozen of these lights, modified them, and have installed 6 of them so far in the cabin.   I since have gone 1 step further,  I found another manufacture who could make the 12 volt LED’ s in the GU10 base…this opened up the lighting options tremendously. Now with just a simple bulb swap all kind of lights could be converted to ultra-efficient 12 volt LED’s. The perfect option for new construction.

The first pic here shows a basic GU10 track light, that costs about $15, add a special bulb and you now have something that can compete with the special marine lights the I found for $250+. The bulbs pictured below the light are from left to right. A 38 bulb LED with Gu10 base 1.8 watts, a single LED high output Spot GU10 base 1 watt. A 20 bulb LED, std screw base 1 watt.

This second picture shows one of the mini can lights that I modified with the 20 bulb screw LED.

I ordered a mixed case of these new GU10 based 12 volt bulbs, I will use the rest of the 6 lights, I already modified, and plan to use 3 of the same mini cans with the new gu10’s.  I wish I had found the second manufacturer before I spent the extra $40 or so for the ceramic screw adapters.

If you are interested in setting up you own Ultra efficient lighting using my 12 volt Gu10, I got a handful…$14 plus shiping, 38 Bulb or the High output spot.  Just drop me a note

Here is a night time shot of the cabin before we got snowed on at thanksgiving.  It is about a 30 second exposure, the lights inside are:  Kerosene lamps on the left, LED’s on the right.

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