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Posted by Adam Meredith on Sep 27, 2015 04:08 pm

#41 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
Thanks for the reply!!! I actually have the pv panels wired in 2 strings of 3 panels each.. optimum output is 18.9 v and 5.29 amps per panel.. That would effectively bring my array to 56.7v and 10.58 amps.. I have it wired that way to take advantage of my charge controller's 100v maximum input to keep wire size down.. Do you see a problem with this set up^^  Sorry, question mark button is broken lol

Posted by Tom M on Sep 27, 2015 02:42 pm

#42 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: newbie, here! had an oddly low state of charge
Well my first inclination is your pv setup. 6 - 100 watt panels- 12 volt should be set up in strings of two, if you are setting up for 24 volts. You said you had 4 panels in series so that would make 48 volts,  or as you mention, 2 strings of 3 = 36 Volts, so perhaps your charge controller is not working properly. If I am looking at the correct controller, it can be set for 12 or 24 volts only and draws 10mA to operate.
 Check any overcurrent device, fuses, relays etc to see if anything tripped.
 Rewire your panels for two panels in series (24 volts) sent into a combiner box, then out of the combiner into the charge controller, then out of the controller to the batteries.
   Read the manual for the controller. Hook up your batteries first. then connect the output from the combiner box from your panels second. Hook up your inverter directly to the opposite end of the battery bank NOT THE CONTROLLER! If you look in the manual it directly tells you not to hook up an inverter, battery charger or high amp load to the controller. You can hook up small 24 volt loads directly to the load terminals if you desire.

So if your charge controller was not working and you had your fridge hooked up to the inverter and the inverter was wired directly to the batteries, then it obviously has been drawing power from the batteries which are not being recharged.


Posted by Adam Meredith on Sep 27, 2015 12:50 pm

#43 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > newbie, here! had an oddly low state of charge
Hello, folks, Im new here.Let me give a complex rundown of my system first.
pv panels: 6 =100 watt renogy monocrystalyne panels
(two strings of 3 panels) roughly 60 volts @ 11 amps rated total output
6 gauge wire running 15 ft from array to charge controller

charge controller: renogy 40 amp mppt controller
4 gauge wire running 2 feet to battery bank

battery bank: 6=12v, 155 ah duracell pro-cell UPS batteries wired in 3 strings to make 24v and 465 ah.
2 gauge wire connecting each terminal no length is longer than 10 inches

inverter: el cheapo "royal power" 1500 watt rms 3000w surge 24v input (modified sine wave)
2 gauge wire connecting bank to inverter, length is 2 feet

load requirements: 1000 wh per day
location: Nashville TN
I've run through the calculators and according to my energy requirements I need 8211 wh and 343 ah from my battery bank
and 400 watts from my pv array for 3 days of reserve. According to my math my battery bank makes 11,160 wh @ 465 ah. Should be more than plenty i would figure.. Heres my dilema. I only had 4 100w panels hooked up in series while i was waiting for my 2 new panels to come in the mail... the only thing plugged in is the small 80w fridge.. I left the cabin for week.. when i returned yesterday to install the 2 new panels and my new mt-5 charge controller display panel i noticed i was only at 24.5 volts and the state of charge was at 40%!! this freaked me out! Yes it was a rainy crappy day yesterday but was bright and sunny all week long.. How in the world could my battery bank get down to 40% state of charge!!! I'm scared to death I'm going to ruin the batteries! I'm new to this but I feel that I've done enuff research to make educated decisions and changes... Any thoughts or guidance would be warmly appreciated! Thanx in advance- Adam

Posted by Ed K on Sep 15, 2015 01:28 pm

#44 -  Renewable Energy > RE General Discussion > Renewable/Alternative Energy, Where to Start
People often talk about using alternative energy in their homes or businesses, but do they understand what those alternatives are? I have built many of my own alternative energy systems and have thought that I had captured a new alternative energy, only to find out that what I had indeed done was used a form of energy that has always been available to folks for many years.  Renewable energy and alternative energy are often used interchangeably since most people do not view traditional energy sources as alternative energy sources. I have written this article to provide some insights into what is “Alternative Energy” and how do we use it?

First Things First
When people think about using alternative energy sources, they often don’t think of the obvious areas to capture energy.  Here are some suggestions for capturing energy that is often wasted in homes and businesses:
   1. Insulation – Unless they are LEED certified, most homes and businesses are either losing a lot of heat energy in the winter months or using a lot of cooling energy in the summer months due to inadequate insulation.  The first area one should look at in thinking about alternative energy is how well insulated their building is.  Insulation in homes and buildings is usually measured in R-Value, which is the resistance to heat flow through a particular substance.  The higher the R-Value, the greater is the effectiveness of the insulation. Typically a home built with 2”X4” outside walls filled with fiberglass insulation will have an R-Value range of between 10 and about 13 depending on what other materials are used for the outside walls and how well the building was constructed. Along with insulation, we must also take a look at the ventilation of those areas such as attics, above ceiling spaces etc.  A well-insulated building with adequate insulation and ventilation can go a long way in reducing energy costs.
   2. Caulking – Sealing up air leaks in a building can also significantly reduce the loss of heat in the winter and the infiltration of heat during the summer.  Many times we neglect to check our door thresholds to make certain that there is no air leaks or perhaps a neglected window that needs repaired.  Checking around the outside of your building for possible air leaks and sealing them up is not only a cost effective way of reducing your energy use, but it also helps keep out pesky critters. 
   3. Energy efficient appliances – More manufacturers are building not only more efficient appliances and machines, but they are also building smarter appliances and business machines.  We need to be looking at how much energy our older business machines and appliances are using and decide whether newer equipment might provide a high enough savings to pay for the replacement within a few years. There are a number of energy gadgets out there that can help us calculate what those savings might be. As more people begin to look at their energy use, they have available to them very inexpensive gadgets such as the Kill A Watt, or the Kill A Watt EZ Meter and for those who want more accuracy and can afford it, the HOBO Plug Load Data Logger. Once you have identified how much energy different appliances within your building are using, you can compare their energy use to what a new appliance uses and how long it would take you to reach a pay-back on that appliance.  Some newer appliances are smart enough to power down when not in use and power back up when they are needed. Some appliances may even be able to calculate how much energy they are using and provide that information to your personal computer.
   4. Energy efficient lighting – We have come a long way in creating better lighting with less energy.  Incandescent light bulbs can not only generate a lot of light but also generate excessive heat.  We have seen the move from incandescent light bulbs to CFL and now to LED lights.  The manufacturers of LED lights have just recently been able to master the art of providing the right amount of light intensity coupled with the right amount of light temperature. When purchasing LED lights it is important to remember that the light intensity is measured in lumens and the light temperature is measured in degrees kelvin.  An LED light that has the lumen capacity and the temperature capacity of a typical 100 watt incandescent light bulb, should be rated at about 1600 lumens and have a temperature rating between 2700 and 3000 degrees Kelvin.

Geothermal Energy
Unless you happen to live in an area where hot springs are abundant, you probably will not be generating electricity using geothermal energy.  There are however ways of harnessing geothermal energy and using it to heat your home or business at a much lower cost than using conventional electric, gas, coal, or oil heating systems.
Heat pumps in the form of air conditioners have been around for decades.  In recent years the technology used for air conditioners has developed to the point where reversible heat pumps can economically heat homes and businesses by converting the existing heat from outside air to a more concentrated form of heat to heat a home or business. Heat pumps do use electricity to generate their heat although they operate much more efficiently than electric resistance type heat sources. One of the problems with heat pumps is that they work more efficiently when the ambient outside air is above 32 degrees Fahrenheit.
Since ground water is usually warmer than outside air temperatures during the winter months in North America, ground water or geothermal heat pumps can produce heat much more efficiently than air heat pumps.  Geothermal heat pumps are becoming more common and have improved both in efficiency and in reliability.

Solar Energy
Generally speaking there are two types of solar energy collection systems; Thermal Solar and Solar Electric or Photo-voltaic. Solar thermal systems can be divided into active and passive systems and within those categories they can be further broken down by the media with which the thermal heat is transferred, for example solid, liquid, air or perhaps even electric. Photovoltaic (PV) systems generate electricity through a process called the photoelectric effect, where materials such as silicon, a semiconductor, absorb light photons and release electrons. The free electrons are captured to provide an electric current.
Site Evaluation – After you have taken care of any energy wasting items within your building, the next thing you need to think about when looking to harnessing the sun’s energy, is how much solar radiation you can expect to occur for the specific site where you want to install some type of solar collection device.  Where does the sun rise and set in the summer and where does it rise and set in the winter?  What obstacles may impede the solar radiation, such as other buildings, structures, trees, hills and or mountains?  What is the average solar radiation one can expect for a particular latitude and location with respect to the average weather conditions such as clouds and precipitation?  All of this information is gathered into a report known as a site evaluation. Armed with a good site evaluation, you can now proceed to the next step of identifying what type of energy collection device would be most appropriate based on needs and the amount of funding available to fill those needs.
Active Solar Thermal heating systems – An active solar air heater can be as simple as a five-sided insulated box painted black on the inside with thermal glass covering the side facing the sun and a fan or blower pulling the resultant hot air into a room.  An active solar air heating system may also have reflectors that move with the sun to reflect additional heat energy onto a collector that may use fans or blowers to move the heated air into thermal heat sinks where the heat can later be used when the sun is no longer shining.  An active solar thermal system may pump liquids through glass enclosed tubes which are exposed to the sun’s rays. The heated liquid can then be stored or used to either heat water or the air in a building.  Reflectors can also be used to concentrate sunlight onto a boiler where superheated water turns to steam and is used to generate electricity. Other active solar thermal systems have the capability of running sterling engines by using the temperature difference between a heated liquid or gas and the ambient temperature within the environment. The sterling engine can then be used to run an electric generator.
Passive Solar Thermal systems – If you have ever walked into a sunroom or garden room when the sun was shining, you no doubt felt the passive effects of the sun as it heated that space. There are various ways to collect and mediate the temperature in a space where the sun’s warmth is felt. One type of passive heating of a space is with a “Trombe Wall”.  A Trombe wall is a wall that has a glass exterior facing the sun and a heat absorbing material on the inside separated from the glass by a thin layer of air. The sun’s rays pass through the glass windows or walls and are absorbed by the wall.  The Trombe wall then releases that heat energy into the air at night. Usually a Trombe wall is made of a very dense material such as stone, concrete or even tanks of water. Most Trombe walls are built with an outside eve that can shade the wall from the summer sun and thus keep from overheating during the summer months.
Heat sinks of concrete, stone, water or brick can also be incorporated into rooms that are exposed to the sun’s heat energy.  In some cases, this could be called a modified Trombe wall where the entire room structure is used as a Trombe wall heating system. The heat sinks tend to absorb the sun’s heat during the day and release it during the night.  One type of passive solar heating system for water is a water tank painted flat black and encased in an insulated enclosure that is exposed to the sun.  As the water slowly flows through the tank, it absorbs the heat energy from the sun and provides for a way to preheat the water before it goes to other active heating systems. Arizona rooms, Florida rooms, or whatever you want to call your sun room can be used to provide passive heat to an adjoining room while also providing a space to grow beneficial plants.
Photovoltaic electric systems – Photovoltaic or PV panels have recently become much more efficient than in previous years.  Not only have PV panels become more efficient, but the cost of installing PV systems has come down to the point where it is more economically feasible to consider having a PV system installed. The electrical energy produced from PV panels can be stored in batteries or fed into the electrical grid to offset the amount of electric power being used from the grid. PV panels generate DC current so they must either be combined with a whole house inverter or the appliances and lights within the house must be capable of using DC current.  A whole house inverter converts a solar-electric array’s DC electricity into AC current for the entire building to use. Some of the new PV panels being developed have micro-inverters attached to them which convert the DC current from the photoelectric cells into a standard 110-120 volt AC current which can be tied into the electric panel of a home using standard wiring.
Photovoltaic panels can be broken out into three basic types: Monocrystalline, Polycrystalline, and thin film or amorphous. The difference in these three types of PV panels is their structure and the efficiency at which they are able to generate electricity.  Monocrystalline panels which are manufactured from a slice of a single silicon crystal and operate at between 18% to 21.5% efficiency, however their cost is usually higher. Polycrystalline panels are built using cells sliced from a block of silicon and will operate at between 14% to 17% efficiency and their cost is generally lower than that of monocrystalline panels. Finally, Thin-film or amorphous panels usually operate at between 12% and 14.5% efficiency and their cost is the lowest of the three types. One other consideration concerning the three types of panels is the amount of space that the panels require for installation.  The higher the efficiency of the panel of cells, the less space is required for their installation. In some cases the same size polycrystalline panels may be more efficient than monocrystalline panels simply because the monocrystalline cells are round and thus require more space on a panel than the rectangular polycrystalline cells.

Wind Energy
One of the fastest growing alternative energy areas today is in the large scale wind turbine industry systems. Although large scale wind turbines can each generate more than 2 Megawatts of electricity, the cost of installing and maintaining small scale wind turbines for small businesses and home owners is much higher than that of small scale solar electric systems.
Most wind turbines especially large scale operations are constructed as horizontal axis wind turbines or HAWTs.  Large scale HAWTs require a fairly large air space area to operate efficiently.  Some environmentalists have concerns about the safety of large HAWTs since the end of the blades can be traveling at very high speeds.  There can be a problem with birds being struck by the blades and there also can be a problem with ice buildup in colder climates where the ice can be flung into the air and possibly damage property or worse yet injure someone standing nearby.
One solution to the dangers of the HAWT is to build a vertical axis wind turbine, or VAWT.  VAWTs require less space for their operation and have a much lower bird strike probability since their vertically rotating blades take up less air space and can more easily be seen by bird populations.  The tighter air space of a VAWT also tends to minimize ice buildup and is therefore less likely to cause property damage or injure bystanders.  Because of the safety issues, VAWTs are becoming more common in urban environments.
There are other alternative renewable energy sources such as water or hydroelectric power and less common sources such as wave power systems. Solar and wind power have the potential to replace other large scale electrical power sources such as fossil fuels without producing as much pollution with the added ability to use existing spaces such as rooftops and farm fields with minor impacts.
As the solar industry continues to produce more efficient solar cells we will have the ability to use more and more of the sun’s abundant energy to provide power to our homes and to our industrial base.

Ed Kirkpatrick

Posted by Amy Beaudet on Sep 14, 2015 10:32 am

#45 -  Renewable Energy > RE General Discussion > Re: Backup solutions for small appliances for 2 to 3 weeks where electricity is NOT
You really need to do a loads list before you go any further to figure out how much power you need. Some of the items you listed don't use much power, but anything that makes heat or cold uses more power than you would expect, and you listed a fridge and a toaster. Check out the loads list calculator here, , and then go to the off grid calculator to see how many solar panels and batteries you need.  Don't make the mistake of buying equipment before you know if it will work for your needs, that's  sure way to loose money.

Solar Queen
altE Store

Posted by Amy Beaudet on Sep 14, 2015 10:11 am

#46 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Sunny Boy vs Solar Edge
Also, if you are interested, I did�  quick video doing an overview of grid tie solar string inverters, DC Optimizers, and micro-inverters you may be interested in watching. I used a Fronius instead of Sunny Boy, but the message is the same.

Solar Queen
altE Store

Posted by Amy Beaudet on Sep 14, 2015 10:05 am

#47 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: Sunny Boy vs Solar Edge
Ah, the eternal debate, string vs panel level inverting. In your situation, there really is no right or wrong choice. Since you don't have shading issues, there really is no need for managing each module. And quite frankly, monitoring per panel is fun, but really not needed. Do you need to know if you have bird poo on one panel that will wash off with the next rain?

With a switchable combiner or pass-thru box, like Midnite Solar's solutions,, you can meet NEC 2015's requirement to shut off within 10' of the panels.

SMA's SunnyBoy TL grid tie inverter also has a great feature that no one else has right now, their Secure Power Supply, which gives you up to 1500W of 120VAC power during the day in a power outage. It's nice to be able to charge up your phone and laptop and other small devices when the grid is out.

Solar Queen
altE Store

Posted by Amy Beaudet on Sep 14, 2015 09:53 am

#48 -  Renewable Energy > Technical Discussion: Solar Water Pumping > Re: Determining panel size to run shurflow pump
You need to determine the dynamic head, which is the total height including the friction loss for the 70' across, in addition to the static head, which is the 20' up you are going. Assuming 1/2" pipe at 2GPM, that's 3.5' for every 100'. So let's say 3' + the 20' static = 23' head.

The ShurFlo is rated in PSI, not head, so searching online for a foot of head to PSI calculator, I see you have to achieve 10PSI.The amps for that pump at 10PSI is 5.3A. Now granted, you will likely need more than that to get it started, but since you need so little water, you don't need to get it running first thing in the morning, so you can wait until midday for the pump to start. I'd probably go with a 100W panel, to ensure that it does have enough current to get the panel started. It has a Max Power Amperage (Imp) of 5.56A.

If you are not using a float switch, what is your plan to control water flow?Will you just have it overflow? Is there something you can think of to do with the extra water? I hate to waste.

Solar Queen
altE Store

Posted by Amy Beaudet on Sep 14, 2015 09:23 am

#49 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: SMK or MC4

"Cross-mating any connector, regardless of the brands involved, is not a UL approved connection. It does not matter that both connectors may have independent UL approvals, as they were tested to their own, specific individual tolerances and specifications.
I have seen numerous connections failing due to cross mating issues. The issue is that the metallurgical chemistry of the contacts are going to be different unless they are from the same manufacturer. Over time, the difference in chemical composition causes oxidation and other issues that can lead to temperature rise and other problems.
Another issue is that, companies don't generally release tolerances for their products. This results in possible gaps in the contacts when cross mating, which leads to arcing, and ultimately connector failure."

I've seen that quote before, which is why I have one foot in that camp. My other foot is in the other camp of being a boater, and making due with what you have available. I think you've come up with a good solution.

BTW, I just wired up the outside horn on our schooner yesterday with heat shrink butt connectors, then wrapped the whole outside wire harness onto the rigging in high quality electrical tape to prevent UV exposure and accidental catching on something while under way. To Tom M's point, we used a dab of dielectric grease in the connector just for good luck.

Schooner Queen
altE Store

Posted by Lion Benjamins on Sep 14, 2015 04:32 am

#50 -  Renewable Energy > Technical Discussion: Solar Electric System - Photovoltaic > Re: SMK or MC4
Hi Tom,
Thanks for the advice.
My plan is to use adhesive lined heat shrink sleeves.
One short piece on each connector covering the last section of cable and part of the connector and one longer one covering half of each of the other two sleeves.
Might be overkill but it's not such a big job for only 4 panels.

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