Emergency Power

2016-06-30 23.27.51The big one just hit. An accident just took out a utility pole. You forgot to pay your electric bill? All the things in your life that require go-go juice just became inert. But it doesn’t have to be that way. A few minutes on Amazon, and a couple trips to some of our favorite places to shop, and you can have plenty of electricity for lighting, communications, and charging your other devices. Read on to build one for yourself.

This is my second build of this type of portable power. My first build was primarily to power my go-box which I will write up in a future post. This system is primarily an auxiliary power source for maintaining a cell phone or tablet, charging a handheld transceiver, and providing light. The genesis of this was my daughter being a camp counselor for a month. The staff live in tents, without access to outlets. So I quickly put this project together to give her some area light, a way to charge her cell phone (no cell coverage but she used it for photos, and they did occasionally have access to WiFi), and as a way to keep her radio charged. The camp generator turns off at 11 PM each night, so keeping radios charged can be a challenge.

So why not just get a generator? Noise, gas, fumes, maintenance? This system is silent, more portable, does not require fuel, other than some sun’s rays for a few hours a day and suites the purpose for which it was built – Charge the main battery all day, and then charge devices overnight, silently, and cleanly.

So… what’s in the kit?

The basic system consists of:

1 X “Kobalt” tool box from Lowes.                                      $19
1 X Harbor Freight 35 AHr AGM Battery                                $70
1 X Photography lighting tripod                                         $20
1 X 10 Watt LED Flood Light                                               $10
1 X Battery Voltage / USB Charger Kit                                 $20
1 X Power Pole Panel Mount                                              $9
1 X 12 Volt LED Touch Dimmer                                           $14
1 X Solar Charge Controller                                                $10
1 X Folding Solar Array (various options)                                 $100 (estimated)
1 X miscellaneous *Wire, switch, solder, crimp terminals, etc.)   $5

Total = about $275

So why did I choose these particular items? The tool box is large enough to hold 2 batteries if I wanted to expand the capacity. But it also doubles the weight to about 50 lbs. AGM batteries are great, but they are heavy. The Harbor Freight AGM comes in at about 22 lbs. The tool box also had these nicely recessed panels on top. I imagine they were there so you would place parts why working on things. For me they were the perfect place to recess the electrical connections and the dimmer. Yes, that is a touch controlled dimmer. While shopping around on Amazon I found this cool, glass top, touch dimmer for 12 volt LED lighting and I knew I had to use it in this project. It is a pain to mount due to a very small ribbon cable in the lid, but I think it looks great and is a nice touch to the project. The dual port USB charger was a simple choice. It is also lighted to make it easy to find in the dark. The voltage meter is just because. When this comes back from camp, I will probably add a small momentary push button switch to see the voltage so the display is not on all the time.

As you can see from the picture of the insides of the box, the wiring is very simple and all comes from the charge controller. The box does have a master switch, but it does not keep the solar panels from charging. They are wired directly to the controller. Another thing I did was color code the Anderson Power Pole connectors in the lid of the box. The cables that go from the solar panel and the light have matching colored connectors as well so it is very easy to connect everything by following the color coding.

The LED flood light is a 10 Watt, warm white, light source. It looks to be about the equivalent of a 40 watt bulb. It provides very usable light in the dark. Since I incorporated the dimmer, I may step this up to a 20 watt fixture, or simply add a second 10 watt for even more area light. The tripod extends to almost 8′ tall which can provide light over a wide area. Yet, it collapses to about 2′, and it is light weight, making it also very portable.

The folding solar array is something I have had for some time. I purchased it several years ago with a project like this in mind. You could substitute just about any similar solar panels you find on Amazon. This array happens to fold up into a pouch size that will fit right inside the box when not being used. The key is many of these type of folding panels on Amazon are 5 Volt only, for charging a cell phone. Those will not work with this system so read the descriptions carefully. Otherwise, most 12 volt (14v to 18v output) panels can be adapted to work with the charge controller I have specified.

The folding solar array, charging cradle, and cables, all fit inside the box when not being used. The foam around the battery is from a computer server. It is closed cell foam and keeps the battery from shifting around inside the box.

Feel free to ask any questions. I will bring this kit to the August GVARC breakfast for folks to look at in more detail.


Category: DIY