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Good point 12vman, I have never done an equalization charge either. In fact I can’t. What I did was to run my six 240 watt panels as pairs running in parallel. I get 32v @ about 15 amps per pair on a bright sunny day. Each pair is controlled by a 20 amp (dirt cheap) charge controller (eBay). The three of them run in parallel to the buss bar. They are pre-set to run a three stage charge cycle with absorption voltage of 28.8v and then float at 26.7v My batteries boil near the end of the charge cycle and seem to maintain the batteries well. There is no equalization option but in the past seven months I have not seen any change in the specific gravity during my monthly maintenance checks so stratification is something I am not worried about.
OK, first of all most electronic devices today run on low voltage DC. The AC that you supply them is converted to 12v, 5v, 3.3v to power the IC’s on board. The power regulator in the device will drop the voltage and regulate it. Since most electronics today are very sensitive to voltage drops, the regulators have filter capacitors used to smooth out line noise so a MSW inverter is no problem.
As for the furnace blower motor, that could be an issue. Either inverter style would work, but the thing to remember about inductive loads (motors) is that they have a heavy start up surge. If the blower motor is say 3/4 hp then the running wattage will be around 575 – 600 watts; however, the surge may be 2,000 watts or more. That is an expensive PSW inverter. And yes, a 1,000 watt inverter may claim to have a 2,000 watt surge capacity, but don’t believe it. Read the fine print for the specs, the surge capacity may be 2,000 watts, but the surge duration will be less than one second (if it’s listed at all). This is not long enough to start most motors. Now I’m not trying to talk you out of a PSW, just be sure you buy a large enough inverter to power your load. That is the only regret I have about my system, 1,000 watts is just a tad too small for some loads. I would like to run a small 700 watt microwave, but the 700 watts of cooking power requires 1050 watts to produce. A 1,500 or better yet 2,000 watt inverter is what I really would like to have. (It’s on my wish list now)
An option to get around this is to get a DC motor for the blower. 12v and 24v motors can be had that run at 1,800 RPM to match the 1720 RPM of most AC motors. There is no surge issue with the DC motor since you don’t run it through the inverter anyway. The only down side to that is the wire will need to be a heaver gauge wire to handle the higher current load. But wire is a lot cheaper than inverters.
One last thing, if I where you I would consider using a laptop rather than a desktop. Laptops use a fraction of the power of a desktop computer, and believe me, using 30 – 40 watts is much easier on your battery bank than a few hundred watts for the desktop. I don’t even use a laptop, I use a netbook. Granted the 10.1″ display is a tad small, but I can use it 24/7 if I wanted to as it runs at around 10 watts or less most of the time, and has never spiked over 26 watts when burning a DVD on the USB powered external DVD drive.
I couldn’t watch the video, but I can tell you that super capacitors are a poor choice for off grid power storage. As Chowan has said the energy density is far less than a lead acid battery. But the real problem is that unlike a battery a capacitor will have a voltage drop that is unexceptionable. A fully charged 24v battery system will have 25.46v when fully charged (Trojan T-105’s) and at 50% DOD the voltage will be 24.2v and at 90% DOD it will still have 23.02v. The capacitor will go from 25.46v (or whatever voltage you choose to store) down to 0v when fully discharged.
Capacitors store electricity, but batteries produce not store electricity. The way a battery works is that the sulfur atom in the electrolyte (sulfuric acid) bonds to the lead alloy forming lead sulfide. This releases Hydrogen and Oxygen from the electrolyte and produces (releases) two electrons. When a load is applied to the battery terminals these electrons can flow and the chemical reaction can continue. When you charge the battery, you reverse the voltage and “Push” electrons back into the lead sulfide causing the sulfur atoms to return to the electrolyte. This is why you don’t want to discharge your batteries to far as that would allow the acid to degrade the lead plates. It is also why the most accurate method of measuring the state of charge of a lead acid battery is by measuring the specific gravity of the electrolyte with a battery hydrometer.
OK, I’ve rambled enough, the short answer is that the voltage will drop below what your inverter can use. To date, there is no more efficient way to store power than a good quality deep cycle lead acid battery.
First off, let me ask you what type of battery are you using? Are these true deep cycle batteries or the “deep cycle marine” type batteries? If they are the marine types then it is likely that the batteries are just at the end of their lives and nothing can be done to restore them.
I have spoken with the folks at my local golf cart shop and the tech support people at Trojan and they both tell me that the electronic battery life extenders do not work. Also the chemical rejuvenaters can’t restore a damaged plate. They can help remove sulfide crystals, but if the plates are covered with lead sulphide then the plates are pretty well shot.
The best advice I can give someone (like myself) who lives total solar for power is to get good quality deep cycle batteries and not to draw then down below 50% DOD. I have 8 Trojan T-105’s arranged in two sets of 4 to give me 24v @ 500ah.
If you did want to do an equalization charge you could isolate 2 of the batteries from the inverter to run the house and equalize the other two. Then swap for the other two the next day.
Here is a piece of advice for bargain prices on batteries. Go to your local golf cart shop and ask about used batteries. Golf cart batteries are true deep cycle batteries and many rich folks will change out their batteries every couple of years just so they never have any trouble with them. My local shop sells the used batteries for $20 each. Just take a volt meter and a battery hydrometer to test then and make sure you get some good ones. As long as the specific gravity of the electrolyte is 1.26 or better you will get plenty of life out of it.
Earth batteries fall into that category of interesting but mostly useless knowledge. They have very low energy density, low voltage, are terribly unreliable and can not be recharged. To get anything approaching useful power the size of the plates would have to be so large as to make the project far more expensive than buying a good battery.
There are many many ways to make a battery. Pennies and vinegar, a lemon and two pieces of metal, etc. but for a reliable power source a FLA (flooded lead acid) battery is the most practical way to go. Period.
You can try it but I wouldn’t get my hopes up. Before spending the money I would suggest you spend an evening reading all the information found on the Trojan web site. http://www.trojanbattery.com this is a great place to learn about batteries. You can also call the Trojan tech support people and they will answer any question you have about batteries. 800-423-6569 ext. 3045
What I believe you will discover is that the batteries you currently use are not really deep cycle batteries, but rather a cross between an auto battery and a true deep cycle battery. An auto battery has more plates than a deep cycle battery but they are thinner. This allows the battery to produce very high current output to drive starter motors but for a short time. Deep cycle batteries have fewer plates, but they are thicker. This means they can’t produce as high of a current output but can do it for extended periods of time. The marine batteries are a cross between the two. They have more plates than a true deep cycle battery and they are thicker but not as thick as a true deep cycle. They are used to start a boats engine so they need to have a high current output, but also are used to power the boat when the engine is off so they need to have longevity. As a result they will last far longer than an auto battery but due to the thinner plates will degrade much faster than a true deep cycle. For off grid use here is a good rule of thumb, if the battery talks about CCA (Cold Cranking Amps) it’s not for you. That tells you that the battery is designed to start an engine so it’s main design isn’t longevity. A true deep cycle battery will give you it’s Ah (Amp Hour) rating two different ways. 5 hour rate and 20 hour rate. A battery produces it’s current by a chemical process and is determined by the speed of the process. For example, my Trojan T-105-RE’s have a 170Ah rating at 5 hours, and a 225Ah rating at 20 hours. They top out at the 100 hour rate at 250Ah. That means if I draw the batteries down completely in 5 hours I will get 170A x 6v = 1020 watts, but if I discharge it for 100 hours to draw it down to nothing I will get 250A x 6v = 1500 watts.
Since my batteries are 6v, but my panels (and the rest of the system) are 24v, I string 4 batteries in series to make a 24v string. I do that to two sets of batteries (8 total batteries) and connect the two strings in parallel to get one battery bank totaling 24v @ 500Ah (at the 100 hour rate). By doing this I seldom draw the batteries down below 20% DOD (Depth of Discharge) that way the plates endure very little degradation from the acid. I estimate my batteries should last in the ten year range.
The biggest factor in a batteries life (assuming proper maintenance) is DOD. The deeper you draw the batteries down the more the acid eats the lead plates. So in the end more batteries in your system save you money in the long run as you do them less harm from lower discharge rates. And the true deep cycle batteries are a must for total solar users like us.
Anyway, I’m rambling again. But do yourself a favor and read what the Trojan site has to offer (and it’s a lot) then talk to their tech support folks before spending any money on something that I doubt will help.
Beast, you are correct. As the battery discharges the plates expand and warp. The heaver the plates the less warpage and the shallower the DOD the less warpage. That is a major cause of “Dead Cells”. Some manufactures make a point of saying that their separators are designed to help prevent plate contact.
As far as drawing your batteries down to zero, I highly recommend that you DO NOT do this as it will in all likely hood damage the battery to the point it will never fully recover. Anything below 80% DOD is highly discouraged by ALL battery manufacturers. 50% DOD is the standard for their life cycle ratings. 15% – 25% is great, but believe it or not less than 10% can actually reduce battery life. That’s why I sized my battery bank to cycle around 20% DOD to get the longest life possible.
Oh Wretha, another thought about the equalization charge, the reason for that is because a battery that sits in one place tends to stratify. In other words the electrolyte has a different specific gravity at different heights in the cell. The equalization charge raises the charge voltage to cause the battery to off gas more than usual to stir up the acid and get the specific gravity more uniform. Since you have four batteries you could take two and put them in your car next time you head into town to “shake up” the electrolyte. A bit crude I realize, but it would serve the same purpose. After all, car batteries and golf cart batteries never need equalization charges.
Well if you can come up with a way to make them work, I’m all ears. But to the best of my knowledge no one has come up with a way to get any practical usage out of them. Lighting a few LED’s sure, but coming up with enough power to run my frig, TV and laptop is a different story. I suppose it could be done, but you will likely spend more trying than solar panels and batteries. I understand that early telegraph companies tried to use them but found it to be unreliable as when the ground dried out they quit working. But if you get even 50 watts out of them I would love to hear about it.
Another good resource for you might be the Yahoo Group “Vandwellers”. These are people who like you live a simple life style in their vans/rv’s/cars.
I recently built a system using 6, 240watt panels and did a great deal of research before buying my inverter. Bottom line their is no black and white answer to which is better as for most things there are tradeoffs. Here is the pros and cons for each.
Modified Sign Wave
Low cost – a 400watt MSW inverter is about $40 at any Walmart. Even a 2000watt inverter will cost around $200-$250
Compatibility – Almost anything will work with them. There are a few things that will have issues but not many. Some clocks have trouble as they use the 60 cycle from line current as a time base. And my Kill-O-Watt meter would not work.
The only real cons are that some CFL’s will hum as well as ceiling fans. But the biggest reason not to use one is that some items especially motors and other inductive loads will not run as efficiently requiring more power consumption and can shorten their lives somewhat.
Now the pure sine wave inverters are much more expensive. I recently bought a 1000watt PSW inverter because as a total solar home I wanted the highest efficiency I could get as power is at a premium for me. The cost was $450 so not only did it allow me more reserve power, but I didn’t have to listen to the ceiling fan complain all night while trying to sleep. Oh, and my Kill-O-Watt meter works with it.
However for the past few months I used a 400watt MSW inverter and powered my 15″ LED tv, media player, laptop, water pump and lights with no problems at all. So which is better? Well the Pure Sine of course, but the question comes down to what are your personal needs? You will not hurt anything by using the $40 inverter and will most likely never see any difference in most cases. If money is no object get the PSW, if price matters get the MSW and see how it works for you.
Just a few thoughts from a newbie off the grider. I to thought that “Self Sufficiency” was the goal. But I came to realize that that was just a word game fantasy. No one here want’s to be self sufficient completely. The very fact that you are connected via an internet connection means you want the goods and services others in the consumer world have to offer. What I came to realize was that what I really wanted was to reduce my “dependance” on the consumer world. So what self sufficiency means to me is the ability to (if necessary) provide all the basic needs like food, water, shelter and a certain level of creature comfort. To that end I bought 3 acres with a stream running through it. I built a 504sq/ft. cabin with 1,440 watts of solar panels and a roof designed for rain water harvesting. This is plenty of land for a small orchard, berry patches, a garden for vegetables and more than enough room for chickens and a rabbit hutch if desired. As for cattle and horses, well, I would rather barter for beef with eggs or fruit than raise a herd myself. But if I did want to raise more meat I would just get a few goats. My point is really think about what your goals are. Are you looking to become a hard working farmer and/or rancher? Or are you looking for what you need to survive hard times and be happy? I now have a home on my own land both of which I own outright. I have electricity for life, plenty of water and come this spring I’ll plant ten or twelve fruit trees, some berry patches and a garden. And I did it for about $35,000 cash. If I had waited till I could afford 50 acres I would still be wishing I was off grid.
All I’m saying here is decide what your real goals are and what is needed to achieve them. I’m not trying to talk anyone out of anything, just recalling how I decided that my 20 acre goal was far more land than I really needed to live a simple more self reliant life.
Just my $0.06 (That’s $0.02 adjusted for inflation) :^)January 5, 2013 at 12:00 am in reply to: My moving journal Going off grid fast, need ideas and advice. #67068
I just left New Mexico after living there for six years. I decided it was not a good place for an off grid home. While there is abundant sunshine for solar and more wind than you can imagine the benefits stop there. While I love the weather the fact is 15-20% humidity is hard to grow crops in. Also the soil is mostly sandy and poor in nutrients. Water perks so fast you need to constantly water a garden and the water tables can be deep, very deep. 400 -600 foot wells are common and 1,500 are needed in some cases. Bringing up water from that deep (assuming you can afford to sink a well at all at that depth) is very power intensive requiring more panels. There is a state wide building code and high crime and drug rates.
Here in Missouri I have rich black soil, plenty of water, a more moderate growing climate, no building codes in county land and a much friendlier population. My solar panels are not working quite as efficiently as they would in Southern New Mexico but at $0.90 a watt I can just buy another 480 watts and break even on power.
I’m not trying to talk you out of anything, just passing on my first hand experiences and thoughts.
vafancudo, that is far to open a question for any detailed response. However, perhaps my story can be of some help. I to am a single guy 52 and wanted to live a far simpler more sustainable life. I had about $35,000 and could see that if I was willing to do all of the labor myself a person could buy a few acres (3 in my case) and build a small off grid house. I built (am still working on the interior) a one bedroom one bath 504sq/ft. cabin. I have 6, 240watt panels and a roof designed for rain water harvesting. Outside of propane (just too convenient not to use) and a cell/internet connection my only expense is food. I now have a comfortable home that can easily be sustained for $500 a month. Even less when the fruit trees start to bare fruit and the garden starts to produce.
So how to get started? Well that really depends on you. Without knowing anything about your situation it is difficult to advise you on your next step. If you have some cash things get a lot easier, if you are starting out with almost nothing then things are going to be very primitive. One option if your resources are few is to live in an RV or even a box truck or van. This is a very inexpencive way to take life easy and do some traveling on the cheap. Many “Snow Birds” RV in the North in the summer and head down south in the winter. Checkout the Yahoo group “Vandwellers”: https://autos.groups.yahoo.com/group/VanDwellers/
If a permanent location is your goal then you must find a piece of land in a part of the country that meets your needs. Finding that land can be tough. If your looking for 100+ acres you can find land fairly easily and cheap per acre; however, small parcels in good locations are becoming hard to find, at least at a reasonable price. I found mine through a Yahoo group. I don’t remember which (homesteads for sale, self sufficient farming, simple solar homesteading). I also found a few good deals on Craig’s List but bought this before actually looking at them in person. Just go to Craig’s list and pick a part of the country you are interested in and look at the real estate for sale. Do yourself a favor and don’t start out in the winter.
While looking for land do some preparation. Start selling off the stuff you will not be bringing with you. Pick up equipment you will need. Read up on things you are not familiar with solar, gardening, construction etc. be prepared when you get there because a half build home isn’t worth the lumber it’s made from in the cold and rain. Unless you have plenty of cash be prepared to rough it till your home is complete.
Anyway I could ramble on for quite some time but if you post more information perhaps I or others here could be of better assistance.