Wiring up you Bug Out Location or Bunker to the sun is not a simple task. The size and costs of photovoltaic panels makes it difficult to generate a lot of off-the-grid power so in addition to the solar gear, you need to modify your lifestyle or replace appliances within your home.


First, abandon the idea of a freezer. Start with the premise that a freezer is simply too expensive, energy wise, and really, ask yourself: What do you actually need to keep cold? Meat, milk, eggs, butter, beer, etc… How cold? Under 40 degrees for food safety.

OK, so you already have a fridge, you can use that right? No. Take your current late 20th century/early 21st century model fridge outside, take the shelves out, flip it on its back, fill it with dirt and start a worm composting ranch in it. Your garden will thank you. Many standard refrigerators and freezers use so much power that battery charge is depleted very quickly. It is not practical to use most standard electric refrigerators or freezers with independent power unless you have a powerful water or wind turbine generator. Super efficient refrigerators designed and tested for solar power operate on less than half the usual power. Some Energy Star rated conventional refrigerators use under 400 - 450 kilowatt hours a year also, but still require a large amount of solar power to run. The best fridge on the market still uses way to much when you have to produce your own energy. The best one out there is still about 1 kw/hr per day. A new GE model that uses 550kw/hrs per models that used 3/day. But if you are off the grid you want to get in the Watt/hr range....not KILOWATT/hr range.

Freezer Conversion:
Buy a late model, energy star rated 7-9 cubic foot chest freezer (one that you can use for your home now, using grid power, and use as a freezer). You’ll also need an external Thermostat. They are 60-70 bucks from Kegman.com, or KegCowboy.com, you might find them a little cheaper shopping around, but that's the one you need.

The thermostat plugs into a 120v source, then the freezer plugs into the double plug, which is controlled by the external thermostat. You put the bulb part inside the freezer to sense temperature, and set the dial to what you the freezer to go to, and STOP running when that temp is exceeded. This simply over rides the thermostat control that comes with the freezer, shutting off the electric power when the selected temp is reached. For refrigeration, you want something around 38 degrees, but definitely below 40 to inhibit bacterial growth.

Now you have a freezer converted to a refrigerator that will only use in the 150 to 200 watt/hr/day range....5 to 7 times better than the very best Upright conventional fridge out there.....meaning you can get by with 5-7 LESS times the power to run it. Keep it someplace cooler than the kitchen if you have such a place ( though don't set it out in REALLY freezing cold weather either....refrigeration compressors can lock up in cold temps )....try to pick a place that is as cool as possible to begin with so the unit isn't having to fight ambient temps, every watt counts here.
Now you now have a power requirement of, say 250w/hrs/day (allowing a little extra in case you live in a warm climate).

Let's also say you want another 250w/hrs/day to run some electric lighting, or maybe do a few other small things, like a radio. So you’ll need a 500w/hr/day system....that's 1/2kw/hr/day. Look at your most recent electric bill. If you're like the average US household, it was 900kw/hrs for a month. That’s 30/day and you're now dropping to 1/2 of 1kw/hr per day? That’s a big difference, so don't start thinking microwave, coffee pot, dryer, AC. Just figure out how to make coffee on a campfire outside or a propane campstove, and hang the clothes you washed in a washtub on a clothes line to dry.

You'll need something that will supply 500w/hrs at 120v. You can invert the power from 12v batteries in this small system (to keep it simple) to 120v. 500w/hrs divided by 12v is 40.16amp/hrs. Don’t forget, you loose some for inverter loss, and other system losses, so round up to 50amp/hrs per day.

Batteries shouldn't be discharged more than 50% of their rated amount, or the number of times you can do that REALLY goes down. Ideally, 20-30% will give you far better life, but let's go with 50. That means you need a 100amp/hr battery (FOR ONE DAY) assuming you're not putting anything back in the battery.

So, let's assume 4 days you don't put anything back in the battery that means you need to buy 400/amp hours worth of battery. You wander down to the local Interstate battery dealer, and ask for that. They have some L16's there for $300 each. Since they are 6v, you need two of them to make a 12v set up. $600. Add another 50 for cables between them and to the inverter later.


Solar Panels:
Now for some solar panels to fill up what you're taking out of the batteries. You need to shoot for that 500w/hrs a day, PLUS enough to fill the batteries if you just went through several crappy solar days (clouds, rain, fog, snow). Figure 4 hours of GOOD sun to be safe....if you get more, great, if you get less, add more to this...but I'll use 4 hours as a safe average. 500/4hrs = 125w of panels, not allowing for any system loss, which there will be, and not allowing for the fact that panels REALLY don't put out what the STC rating says.....so up that by 50% that right off or 200w of panels. Now that only keeps up with ONE day of use, remember, so if you want to "refill" the batteries from 4 days of crappy weather you need 800w of panels.

A quick check over on CHEAPEST PANEL PRICES shows panels can be bought in the $1.25/w range....say $1.50 after you pay shipping on a small order, so you can expect to pay something like $1200 for the panels to your door.

Charge Controller:
You have to have a charge controller mainly to keep from overcharging your batteries. But the new generation of CC's, called MPPT (MaxPowerPointTracking) also have the ability to use about ANY panel, meaning you aren't limited to just "12v" panels. which only go to about 130w in size. Many of the newer panels run on up in the mid 200 range, and operate on voltages in the 30v range.

So, lets pick an MPPT charge controller that lets us use 800, but is still "somewhat" affordable. Outback products has the FM60 and is rated for 800w of panels on 12v output....exactly what you need.

Inverter:
You can buy little cheapy inverters but they are only 60-80% efficient in converting DC to AC, as well as having a fairly short life in general, or get a decent Outback inverter , the FX2012T 2000 Watts, 12 VDC Inverter/Charger for $1700 but it will last many many years, and perform like a champ.

Total Spent: $4075
Inverter $1700
Charge Controller $525
Solar Panels $1200
Batteries and cables $650

(Double the Panels and Batteries plus upgrade the Inverter and charge controller= $6500/for almost .87kw/hr system with 1 week back up.)

The best source for current information for family residences off-the-grid, including a store that sells select gear, is Backwoods Solar. They have a large website, a paper catalog of gear and advice, and they keep up with the latest products such as Harris Hydro system with Xantrex and Morningstar products. Kyocera and Evergreen solar modules Bergey wind turbine and Kyocera solar modules ES&D hydro turbine plus Kyocera solar modules on a tracker with Xantrex power products. Shell SQ175 modules Xantrex inverter and transformer.

Heavy Duty Batteries:
There is a new generation, deep cycle, flooded lead acid battery offers high capacity and heavy duty plate grids which resist positive plate breakdown. The plates are double insulated with glass mat and polyethylene envelope, eliminating the possibility of separator misalignment, cracked separators, and shorting. Each 2 volt cell is built into its own lightweight container made of durable polypropylene. The cells are then assembled into a tough outer container with a removable lid. Even if this outer container cracked, acid spills are prevented and the battery still operates. The individual cells are bolted together allowing the battery to be disassembled and the cells individually removed for easy on-site installation. Free battery book and Hydrometer included with each purchase. Rated at 3200 Cycles at a 50% Depth of Discharge. B-S models have a 2 year free replacement, 7 year pro-rated. KS, CS & YS Models 10 year warranty: three years full warranty; and then seven years pro-rated warranty. ET 135W Poly, 12V, $319 ET Solar ET-P636135 Polycrystalline PV modules generate very reliable solar power for on-grid and off-grid applications, as well as residential and utility-scale solar power systems. These polycrystalline photovoltaic modules are designed and manufactured to comply with very strict international quality standards. Strong design, procurement and production efforts ensure that these products generate high solar power and take up small spaces. Backed by a 25-year warranty on power output, ET Solar modules bring lasting values. Made in China, UL listed for the US and Canada.