February 27, 2021

Versatile Photovoltaic Power – Part 2, by Tractorguy

(Continued from Part 1. This concludes the article.)

Refrigeration

Refrigeration will likely be one of the biggest loads on your solar power system, if not the biggest. I went back and forth for a long time on the propane vs. DC electrical discussion to run refrigeration. I finally came down on the side of DC refrigeration for two reasons: 1. The rugged terrain around my Buglout Location (BOL) would make it extremely difficult for a truck to deliver a tank and refill it; and 2. The availability of bottled gas after a grid-down or TEOTWAWKI situation would be pretty much limited to what you have on hand. Fortunately, the demand for refrigeration in the winter is much less, coinciding with the less energy you will get from your panels due to the shorter days.

12V refrigerator/freezers, such as the Whynter line, are commonly available and are a strong argument for having a 12V distribution system, or at least a 12V output on a higher voltage system.

Log Splitting

No, I’m not kidding here. I split wood with solar power. I am an aging Baby Boomer and did not have very much upper body strength even back in my prime. My BOL is wood-heated and I have eight acres of woods to support that. Sawing wood by hand is not too bad — splitting wood by hand is another story. I have read several articles here on SurvivalBlog about how splitting wood is easy, you just need the correct type of ax, or weight of ax, or wedge, etc. We cut a lot of wood last fall, and this winter, I thought I would spend an hour or so per day splitting it. I have a good axe and splitting maul, so I sharpened them up good and started on it one day. Oh My God. I spent a half-hour swinging both the axe and splitting maul with all my might and having it just bounce off the end of the log. Finally, after a half hour, I succeeded in splitting three logs. My shoulders ached and I was exhausted. Obviously, if I was going to have to split wood by hand to keep warm, I was going to freeze to death!

Some kind of log splitter was obviously required. I did not want to go the gasoline engine powered route because of the noise, the unavailability of fuel after a grid-down event, and the inability to use it outside. I toyed with the idea of putting a hydraulic pump on my two-cylinder Onan diesel generator to power a log splitter – that had the advantage of more efficiency than a gasoline engine, I had a lot of diesel fuel stored which would keep indefinitely, and the unit is installed inside and vented out through the exhaust stack previously used by the furnace. However, the limited supply of fuel after a grid-down event concerned me.

So I went ahead and searched for a three-point log splitter – this is basically just a frame, hydraulic cylinder, and wedge, that uses a farm tractor’s engine and hydraulic pump as its power source. This would be the basic unit, minus the power source to run it. I found one locally on Craigslist at a farm liquidation sale for a low price. Shortly thereafter, I was watching a liftgate truck unload at my job and the lightbulb went off in my head – I could drive the splitter with a DC hydraulic unit like is used to power a liftgate truck! I found a used one on eBay and bought it. I had to do some minor repairs to it, but when I got it running it would make over 2,000 PSI dead-headed. For a test, I powered it off the starting battery for my diesel generator, hooked it up to the three-point splitter, put a log in the frame, pushed the lever to the FORWARD position and the wedge easily powered its way right through the log. Success! It does not recycle as fast as a gasoline-powered one, but probably would if I got a higher capacity power unit.

Skeptical of how fast it would run the batteries in my solar power system down, I hauled it up to the BOL and hooked it to the solar battery bank. It was a bright sunny winter day, and I started splitting logs with it, thinking I would stop when the batteries were run down. I was hoping for fifteen minutes of run time. Two and a half hours later, I was still splitting logs! The six solar panels were putting almost twenty amps into the battery bank and were holding the battery voltage at 13.5 volts. I couldn’t believe it! I was worn out from loading the splitter and stacking wood before I ran out of battery power. As a bonus, my wife can split wood too, and we can split wood in the basement wood storage room and stay comfortable while we’re doing it, even if the weather is inclement outside.

Lighting

As I mentioned before, two 10W LED Edison screw base bulbs in a standard ceiling fixture will light up a room just as well as two 60W 120V incandescent bulbs, while only consuming 1.6 amps at 12 volts.

With OPSEC in mind, night lights along the floor of your BOL, to allow you to get around in the dark, are a great addition. Once your eyes become adjusted to the dark, you don’t need very much light. I have built night lights out of a single white LED (Cree part #C512A-WNS-CZ0B0152, Mouser Electronics catalog # 941-C512AWNSCZ0B0152, or Newark Electronics stock #61T8770, $.17 each), a series resistor, and a standard lighter plug.

While the normal operating current of a single LED is 20 milliamps, or .02 amp, the white LEDs are way too bright at that current level. Limiting them to .3 milliamps, or .0003 amps, with a 33K ohm series resistor to run them on 12 volts, results in a dim glow that enables you to see to walk around at night, but cannot be seen outside of the house. When connecting the LEDs, look carefully for a flat spot on the collar at the widest part of the LED case. The lead next to it is the cathode, or negative lead. It should be connected to ground, or the shell on the lighter plug (assuming you have a negative ground system) and the other (anode) lead should be connected to the center (hot) pin on the lighter plug, through an appropriate resistor for the current and brightness you want the LED to make. Don’t try to run the LED without a series resistor or it will burn out the minute you connect it to a current source of more than 20 milliamps. Once I got the series resistor and the brightness like I wanted it, I then put heat-shrink tubing over the whole thing for insulation.

Single gang stainless steel wall plates with a standard automotive lighter fixture in them are available on eBay, and I have a number of them in wall outlets in my BOL, with the homemade night lights plugged in to them and aimed at the floor.

Remote Buildings

The barn at my BOL was a challenge for solar power. It is in a heavily treed and shaded location, and is too far from the house to run DC lines to it without excessive loss. Fortunately there is no refrigeration or other high-current draws on its system, only lighting, so the panel requirements are much less. The main door faces South and has the most sun on it of any part of the barn, so I went with a single 180W panel mounted in a frame above the door. In the picture you can see the three pieces of angle steel in the bottom of the frame that allow the panel to be set in the summer, spring/fall, and winter positions.

I have three 60W equivalent Edison base LED lamps in standard ceiling fixtures for the main part of the barn. In order to light the workbench, I got a set of 12V under-cabinet lights off E-bay and mounted them under the shelf immediately above the workbench. They are each one foot long, are rated at six watts each, for a total of 18 watts. They really light up the workbench well.

The entire barn system. The extension light hanging there is the 12V conversion that I refer to below.

Miscellaneous

If you have a backup generator that has a starting battery, run a feed from your solar power distribution over to it, connect it to the starting battery through a diode (to prevent backfeeding) and a automotive brake light bulb for a current limiter, and your battery will always be fully charged and ready to start the generator, even after long periods of inactivity.

Locating your solar system batteries near where your vehicles are parked, or at least one set of them near where your vehicles are parked, gives you a convenient source of power to jump-start a vehicle if required.

I took a standard hanging extension light fixture, such as is popular for vehicle maintenance, cut off the 120V plug, and replaced it with a lighter plug, screwed a 10W 12V Edison base LED bulb into it, and have a handy extension light for working on vehicles. Again, I have several of the wall plate lighter outlets located near the vehicle parking area to plug it into.

A backup generator with a heavy-duty battery charger (thirty amps or more) is an excellent idea in case of prolonged rainy weather rendering your solar panels unable to keep up with your system demand. Obviously OPSEC is important, but running it for one hour and putting thirty amps back into your batteries will help restore them for a while until the sun comes back out.

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