Harper Texas Weekly Volume 2 Issue 1 - January 2014 - FREE You can also find them at the auto parts stores if you don’t order off the internet or don’t want to go to San Antonio.
Solar Power Anybody? Have you been looking for a way to add some lights to that barn out in the back pasture?
The parts described above will power the refrigerator for about two days before the batteries go dead.
How about a small refrigerator at that remote hunting cabin you have?
Now we need to figure the charging portion.
I’m pretty sure a lot of you have been wondering what you could do with it, and how cheaply you could do it so that you didn’t have to pay the power company to build a line, or monthly bills.
This used to really screw with my mind because I would try and calculate it all as one system, when in fact it actually is two totally separate systems. If we divide 1,260 Watts (needed to recharge the battery) by 140 Watts (supplied by the Solar Panel), we find that it will take 9 hours to charge the batteries back up which is doable most days around this part of Texas with the sunshine that we get.
I’m pretty good with technology and even I had a hard time wrapping my head around this concept because it seems that every avenue I followed gave me a different version of what works and what doesn’t. But lately it has come together and I’m going to be doing more and more with it and because I believe you too might be interested, I am going to share my lessons learned with you if you want them? Let’s start with a very simple system and let’s use a small apartment size refrigerator that only draws 75 Watts and runs off of 115 Volts at .64 Amps.
So far we are looking at $232.13 for the refrigerator (plus shipping, tax, etc.) and $200.00 for two batteries and $438.90 (plus shipping, tax, etc.) for the solar system which isn’t cheap, but if it is done right, you will always have a cold drink at your remote location if you want it, and you won’t have to pay a electric bill to do so. Sounds like magic, doesn’t it? Or smoke and mirrors? I’ve been trying to figure out how to do a system like this for sometime and it finally clicked the other day. I think what confuses most of us is that we try and figure the whole system as one complete system, but it is not.
You can get by for more days (in case it rains, or is cloudy) by adding more batteries. Keep in mind that you will need to add an additional Solar Panel if you do that, or else it will not be able to put out enough Watts to charge the batteries completely. There is probably some space to fiddle with on either side of the equation, and as I run this system for awhile, I will occasionally give update reports so that you can decide if you want to do something like this for your hunters cabin, or that barn in the back 40.
Lights Only?
As an example, those two batteries put out 2,520 watts (210 Amp Hours times 12 Volts). And that refrigerator draws 1,800 watts (75 watts * 24 hours). This particular model is a EdgeStar 3.1 Cu. Ft (Model CRF320SS) that retails for $357.13 and Compact Appliance normally has them on sale for around $232.13.
Which means we could run the refrigerator for a little over 1 day using only the two batteries, and then those batteries would be dead. But there is a catch as everything I have read says you do not want to draw the battery down more than 50% or you will most likely ruin it, which now means that we could run that refrigerator for about half a day. The formula that I finally figured that works can be expressed this way: 105 + 105 = 210 Amp Hours for the Battery Times 12 Volts = 2,520 Watts Total Times 50% = 1,260 Watts Available Less
Now if you only want to put some lights in that remote barn, you can get by for a lot less money. I bought this system from Harbor Freight for $169.99. It is a 45 Watt system that comes with the charge controller, and it is designed to run two lights.
Now let’s add two batteries that we can pick up at Tractor Supply in Kerrville or Fredericksburg.
75 Watts for the Refrigerator Times 24 Hours = 1,800 Watts Total
It also has a cigarette lighter type plugin and a USB port to recharge your cell phone.
This is a Deep Cycle Marine/RV Battery that they have that is rated at 105 Amp Hours and costs $99.99.
Times 50% = 610 Watts Required (refrigerator only runs about half the time)
This is the system I use in my cabin to supply the lights and charge my cell phone.
Now let’s add in a 140 Watt Solar Panel, a Charge Controller to keep the battery from overcharging, or getting drained too low, and a breaker box and some wires for around $438.90.
This is the first portion.
So far it has only required one 12 Volt Battery that I took out of my pickup when I put a new one in, and I am happy with it .
We will cover the charging in a bit. Now we need something to convert the DC Volts from the Battery to AC Volts that will run the refrigerator. I am using a 400 Watt Inverter that I brought from Harbor Freight for $29.99.
With an inverter, I can run a drill, etc., but not for a very long time, so you need to keep that in mind if you’re thinking about going this route.