photo credit: twentyeight
For several months I’ve been exploring different options for generating electricity in a TEOTWAWKI scenario. My initial search revolved mainly around gasoline generators, and I decided that I would get a Honda EU2000i. This is a great unit that can also be converted to accept not only gasoline, but propane and natural gas as well. This makes it a versatile unit worth considering if you have a source for any of these three fuels.
However, the more I thought about it, the more I realized that this was not a good option for my needs. I ultimately decided not to buy the generator for a couple reasons. First, generators are loud. If you are in a crap-hit-the-fan scenario and are using your generator, then you are likely the only one in the area making that much noise. You will stand out and attract unwanted attention very easily. Second, the usefulness of this generator is directly dependent upon the source fuel. When your supply runs out, then the generator becomes a heavy paperweight. You could barter for additional fuel, sure—but in a dire emergency, the general supply of oil-based fuels will likely quickly deplete. Prompted by Wade’s post, I had been considering acquiring a propane tank for long-term emergency use. But even still, the usefulness of this item has a hard limit that acts as a barrier for utility.
For these reasons, I decided to divert my attention elsewhere. I briefly explored wind generators of various types, but ultimately felt that these weren’t a good option. Most of them are very bulky units made primarily to be affixed to your home or other unit (RV, boat, etc.). So, I began to look into solar power. I was lucky to have access to an acquaintance that answered all of my questions, and helped me determine what would be best for me. Along the way, I discovered a few important items that deserve consideration:
- We are very spoiled living on the grid. To produce the amount of electricity we consume on a daily basis would, if using alternative energy sources, require a significant investment.
- Many system solutions do not lend themselves to both integration in your home and portability. Meaning, you either set up solar panels (or a wind generator, or a propane tank, etc.) to feed directly into your home grid, or you instead build a portable system that will not be integrated. A “hybrid” system is possible, though not common. (Who wants to go up onto their roof every time they have to unmount a solar panel to take camping?)
- A modest investment in solar technology will not produce anywhere near the amount of electricity we regularly use. Thus, a smaller system would likely not be a wise option for integrating into your home, since it would not have much of an impact at all, and thus would not be worth spending the money on integrating.
My decision was to get a portable system that would lend itself to bugging out, camping, or going mobile for whatever reason. Likewise, I could simply leave it in the backyard to be used at home as well. Here are the details on my configuration (recommended and built by an acquaintance of mine here in Utah valley; if interested, he can help you get a system you like as well):
Obviously, the first need for any system is one or more batteries to store your generated electricity. The first battery in my system, and the base of the entire unit, is the Xantrex 1500
. This is a solid, durable package that contains a battery (well, three 17-amp batteries connected together in parallel) and inverter. Here’s part of the product description:
The XPower Powerpack 1500 is a portable power system that produces household electricity for products rated at 1500 watts or less. A clean and quiet alternative to a generator, the XPower Powerpack integrates a 60 Amp/hour AGM battery with a 1500-watt inverter and produces a 3000-watt surge. This system is built to run a range of appliances such as a standard size refrigerator and microwave oven, and office equipment such as a computer, monitor, and fax machine.
The XPower Powerpack 1500 consists of a battery pack that stores electrical energy, state-of-the-art electronics that convert 12 volts from the battery pack to household power, an AC power panel that contains two standard outlets, and a DC power panel that is used to run 12 volt products. These components are packaged into a rugged “cart” with a removable waist handle that allows XPower Powerpack 1500 to be wheeled from room-to-room or outdoors over rough terrain.
Xantrex battery (bottom unit) with cart attachment
For those who don’t know, AC outlets are the standard, three-prong type found in your home. An example of a DC outlet is your car cigarette lighter. So the unit comes with two AC outlets, and one DC outlet. Without needing any solar panels, you could simply plug this battery system into your home AC outlet and leave it connected—the trickle charger will ensure that the battery remains full at all times. If you needed to bug out, you could then grab the battery and go. However, once the battery runs out, and without a way to generate more juice, you’re out of luck. But for your basic weekend excursions where you need to charge camera batteries or power a lantern, it is a great option.
Xantrex AC outlets
Xantrex DC outlet
Note that the batteries in the Xantrex are AGM cells, so they don’t have the out-gassing problems that a wet car-type lead acid battery would have. This means that they can be safely kept inside your living area just fine, whether that’s a tent or a house.
In addition to the Xantrex, I got another battery to be able to store more juice. This one is a 55 Amp/hour AGM battery, which simply sits on top of the Xantrex unit and connects in parallel.
Second battery stored in battery box
An important lesson I’ve learned regarding lead acid batteries: in order to extend their life as long as possible, it is important that they not be depleted more than half their full capacity. If the batteries are used to their full capacity, the lead plates start to get eaten away, thereby reducing the lifespan of the battery itself. In some situations it might be necessary for you to use everything the battery can give, but where possible, it’s best to take care of your battery (by using it as sparingly as possible) so it can continue to take care of you.
Solar panels have dropped in price recently, so now is a good time to buy if you’re in the market for one (or more). I ended up purchasing two 64-watt US64 solar panels. These panels have no glass (unlike most) and are thus quite durable, have a “triple-junction” technology that allows for greater efficiency in generating electricity, and are connected in such a way (unlike many panels, oddly enough) such that if one cell group is shaded or blocked somehow, the rest of the cells are unaffected and continue to perform. Here’s a description:
The “triple-junction” technology used in the US64 uses three layers of semiconductor material so that the junctions are stacked on top of each other. The bottom cell absorbs the red light, the middle cell absorbs the green light and the top cell absorbs the blue light. This spectrum splitting capability is the key to higher efficiency in a smaller panel.
Under higher operating temperatures, solar panel performance changes. This depends on temperature, solar spectrum (light color) and related effects. The US-64 is less affected by temperature than monocrystalline or polycrystalline solar technologies. The result is up to 20% more delivered energy. The size will be slightly larger than a competitive panel of the same wattage but performance is much better in foggy or partially shaded conditions.
Eleven cells are connected in series to produce the required voltage for 12 volt battery charging. The cell assembly is laminated (sealed) in flexible and durable weather resistant polymers that provide long life and high reliability.
Two US64 solar panels attached to batteries
Another option I had previous considered was the Sunforce 60-Watt Solar panel assembly
. However, after reading reviews and upon the recommendation of my acquaintance, I decided that this (fairly popular) system would not be good for a few reasons: the panels are glass-covered and thus breakable; the panels only have a five year warranty (as opposed to the 20-year guarantee many other panels have); the included charge controller and electronics are not very weather-proof; and the panel’s chemistry is amorphous, which is often prone to breaking down after a number of years of continuous use.
So, US64 it was. Each of these (US64) 64-watt panels generates a maximum of 3.9 amps. With the two of them hooked together (128 watts, 7.8 amps), the system needs a charge controller to handle the higher load.
To handle the 7.8 amps (maximum) produced by my two panels, I got a Morningstar SS10 charge controller.
Charge controller attached to Xantrex cart
A charge controller is similar to the voltage regulator in your car. It regulates the voltage and current coming from the solar panels going into the battery. 12 volt solar panels can sometimes put out more than just 12 volts, so if there is no regulation the batteries will be damaged from overcharging.
If I were to add another 64-watt panel, then I would need a larger charge controller to handle the extra load, since my three 3.9 (max) amp panels would be putting out a maximum of 11.7 amps—more than the 10 amp controller would be able to handle.
Being the OC person that I am, I want to know that this system is working properly and efficiently. To that end, I also decided to purchase a Doc Wattson meter so that I can quickly see how well the system is doing both in terms of juice going from the panels to the battery, as well as how full the battery actually is.
Meter attached to measure generated electricity from panels
So, the obvious question for those still interested at this point is: “what did this system cost?” For the parts listed above, wires, connectors, and labor for this acquaintance of mine to build it all for me, the total came out to $1425. Here’s the breakdown:
- $400 – Xantrex 1500
- $150 – external 55 amp/hour AGM battery w/ cables
- $710 – Two US64 panels, wired and connected
- $65 – Morningstar SS10 charge controller
- $50 – cables/connectors
- $50 – labor
What’s it good for?
In order to know what you’ll be able to use on a similar system (or any system for that matter), it’s important to make a list of what items you’d be wanting to use (wheat grinder, portable heater, lights, refrigerator, well pump, battery charger, etc…) in a TEOTWAWKI scenario, and then measure how much power each device uses. The best method for obtaining this information is to purchase a Kill A Watt
. Using this compiled information, you would then have a much better idea of how many batteries and panels you would need to accommodate your electricity requirements.
My current setup is to be considered very minimal. Going to the halfway point for my batteries would give me around 50 amp/hours of juice. Running at 12 volts, this yields 600 watt/hours. So, on a single (halfway) battery charge, I could run a 100 watt light bulb for six hours, a 200 watt fan for three hours, or a 1200 watt space heater for half an hour. Here’s a calculator for making similar calculations. You can see how this system is optimal for light, intermittent use—any greater load requirements would necessitate a much larger system capacity. Also note that these calculations are not entirely accurate, because they do not take into account the loss of current through inversion (converting DC to AC). Also, the discharge of a battery is non-linear, so heavier loads will drain the battery’s amps much faster than a lighter and longer load would.
The thing I like about this system is that it’s rugged (solid battery pack cart system, no glass in panels) and portable. I don’t plan to use it very often, but I have it set aside for when I go car camping and if I were to ever need to bug out somewhere. I must admit, the geek in me gets a thrill out of watching the meter indicate that I’m using sunlight to power my gadgetry. Solar power FTW!