Choosing Your Charge Controller
For any battery-backed DIY solar panel system, choosing a PWM charge controller, rather than a MPPT, will be less efficient, but more cost effective. To calculate the proper size for your charge controller, simply divide the solar wattage by the battery voltage. Again, leaving some room for error, in this instance, a 20A charge controller will work well .
Charge Tools In A Shed Or Workshop
Adding solar power to your workshop opens up endless possibilities. You can quickly get started with a small 40w panel to charge up a couple of power tools, or you can take it further with a full array.
When installing a solar panel in your shed, you will likely need to add an inverter to your system. An inverter converts DC power from your panels into AC like that found in your home sockets. This will allow you to supply electricity to your usual tools and their chargers.
Rating Of Charge Controller:
Since our system is rated at 12V, the charge controller is also 12V.
Current rating = Power output of Panels / Voltage = 125 W / 12V = 10.4 A
So choose a Charge Controller of 12 V and more than 10.4 A.
If you like to reduce your system cost you can make your own PWM charge controller. For step by step instructions you can see my instructable on building a PWM Charge Controller.
You may also like my new 3.0 design of an Arduino MPPT Solar Charge Controller.
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Freezer Solar Panel Requirements
To be clear, this guide is for freezers only, and does not include refrigerators with freezers. We have a separate guide if you want to run a refrigerator on solar power. While there are all kinds of freezers, it is possible to use the following guidelines and determine how much solar power you will need
The formula is: find the freezer power consumption in watts and add 20%. The result is the minimum solar panel size you should use. The following chart shows the most common freezer sizes, their power consumption and the minimum solar panels required.
|18 to 22 cu ft.||350W 500W||600W|
Solar panel power output should be rounded off to the nearest size available. If a 9 cu. ft. freezer requires 144 watts of solar power, get a 150W PV module. We recommend the Newpowa 160W solar panel as it is made of high quality monocrystalline and can be used in homes, RVs and boats.
If your 15 cu. ft. freezer needs 528 watts, two 275W or 300W solar panels will do. A good choice would be the Huajin 300W flexible solar panel as it has a high efficiency rating and works in different environments.
As you may have noticed the power consumption varies quite a bit. That is because freezers come in a wide range of sizes, shapes and designs. Some models are also more energy efficient than others.
Freezer power consumption is affected by several factors, so under certain conditions a freezer may consume power than what you might expect. This is particularly true if the freezer is full.
Benefits Of Small/portable Solar Panels
Its easy to discount these small solar panels as not being very useful. In fact, despite their size, they can be an excellent source of renewable power. Here are a few reasons why you may find them useful:
- Portability They can be light and portable. Some of the larger rigid panels are still quite heavy, but they can include handles to make them easier to carry, and most can fit in the trunk of a standard family car.
- They work in remote areas If youre going camping or live in a remote area, a small solar panel can be set up quickly to charge your batteries, warm your food, run your lights or heat your tent.
- They are surprisingly powerful A small solar panel may be all you need to run several appliances. You will be surprised at how much power a small solar panel in direct sunlight can produce.
- They are a renewable energy source Solar power is an abundant source of clean energy. Even though you wont always have strong sunlight, many panels only need an hour or two to provide enough power to charge a small battery pack.
- They are cheap to run Once youve bought your kit, it is unlikely you will need to spend anything else. With a generator, you have to buy it and then keep topping it up with fuel. A solar panel gets its power from sunlight, which, despite not always being present, is always free.
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Which Solar Energy Equipment And Materials Do You Need
In a rapidly expanding renewable energy supplies market, you have many choices for every component you must integrate to make your DIY solar system work efficiently during its entire operational life. Heres a list of the major parts for most solar systems.
After all the headwork and logistics are done, you move on to the legwork: installation of PV panels on racks or poles somewhere on your property, then connecting them to your home electric panel. Depending on whether you opt for grid-tie, off-grid, or a hybrid system, further electrical connections may be needed to get everything up and running.
Selecting The Correct Size Power Inverter Battery Cables
It is very important to be sure you are using the appropriate cable size for your inverter/battery. Failing to do so could lead to your inverter not supporting full loads and overheating, which is a potential fire hazard. Use this as a guide for choosing the proper cable size, and be sure to contact a professional electrician or our tech team with any additional questions you may have.
1. What size inverter do you have?
2. What is the DC voltage of your battery bank?
3. Now divide the inverters wattage by your battery voltage this will give you the maximum current for your cables.
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Using Alte’s Loads List Calculator
Confused about determining how much energy you will need for your off-grid solar electric system to create? That’s where our loads list calculator can help. The altE electric loads list calculator will help you tally all of your appliances to get the how many watt-hours per day your system will need to cover. Take a look at the video then head over to the loads list calculator page to get started.
How Much Do Solar Farms Cost
Multiple factors will influence the actual cost of setting up a solar farm. These factors may include the location of the farm, available sunlight hours, and more. Ideally, a solar farm in the utility-scale level will be at least 1 MW in size. This size of a plant can supply power to as many as 200 households.
According to First Solar, which is a top commercial power provider, solar installations at such a size can cost around $1 per every watt. In total, this will make $1 million for a 1-megawatt solar plant.
Sounds strangely cheap? Yes, it should.
When comparing this to the cost of a residential installation which can cost around $3 to $4 per watt, this may seem cheap.
The difference in price is brought about by the economies of scale concept. Therefore, the larger the plant, the less the cost of installation.
The above cost is non-inclusive of the license fees, and value of the land. For example, the solar farm land requirements for a 1-megawatt solar plant is around 5 acres.
On average, 1-acre solar farm, cost about $500 per month to lease in the United States. The cost of land for 1 MW plant will, therefore, translate to $2,500 per month on average.
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Gear Required For A Grid
In a grid-tie, sometimes called on-grid, solar setup for rooftop, there are a few basic components needed for proper functioning.
- PV panels
- Mounting hardware
- Pure sine wave inverter suitable to a grid-tie setup
- DC or power optimizer
- Grid disconnect
- DC disconnect
- Combiner box
Note: There are three different types of inverters that could work in a grid-tie system. Whatever your choice, make sure its a pure sine wave type of inverter. .
String inverters are the most economical if you have a south-facing home with no shading issues. With this inverter, electric current from strings of several panels each are connected and feed into the inverter. If one panel in the string is affected by shading or it malfunctions, energy output from that entire string is reduced.
String inverter with a DC optimizer technology
A string inverter with DC optimizer technology overcomes this problem. A separate power optimizer is attached to each solar module in your array and functions independently of all the rest. All the DC coming from the optimizers is channeled to the inverter where the DC-AC conversion happens.
With this type of inverter, shading or malfunction would affect only specific panels . It is possible to monitor each panels operation with this type of inverter.
A microinverter is a type of inverter attached at each panel. DC to AC conversion occurs there. Then, the AC is channeled together from your roof and feeds directly to your home AC breaker box.
Selecting The Solar Cable
The current generated from the solar panels should reach the Battery with minimum loss. Each cable has its own ohmic resistance. The voltage drop due to this resistance is according to Ohms law
V = I x R .
The resistance of the cable depends on three parameters:
1.Cable Length: Longer the cable, more is the resistance
2. Cable Cross-section Area: Larger the area, smaller is the resistance
3. The material used: Copper or Aluminum. Copper has lesser resistance compared to Aluminium
In this application, copper cable is preferable.
You can calculate the cable size by using RENOGY online calculator.
You need to enter the following parameters :
1. Solar Panel Operating Voltage
2. Solar Panel Operating Current
3. Cable Length from Solar Panel to Battery
4. The expected loss in percentage
The first two parameters can be easily found from the specification sheet on the backside of the solar panel or from the datasheet. The cable length depends on your installation. The loss percentage considered for good design is around 2 to 3%.
In the earlier step, we have already finalized the Solar panel, the rating. From the Solar panel specification sheet Vmp = 36.7V and Imp = 6.94A . Let the distance between the Solar panel and the Battery is 30 feet and the expected loss is 2%. By using the above values in the online calculator by RENOGY, The cable size is 12 AWG.
The calculation screenshot is also attached for reference.
You can buy the Solar cables from or Aliexpress
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Solar Kits Eliminate Guesswork
You can cobble together your own system with individual parts, but that can be dicey. Matching the right collectors, charge controller and the battery takes some know-how. If you want AC power, youll also need an inverter that converts DC voltage to AC for outdoor solar outlets. All those components must be compatible and work together flawlessly or youll have big issues. Plus, the components have to be suited to the climate you live in. Some can handle extreme heat, cold or dampness while others cant. So unless you just want occasional short-term lighting, we recommend buying a kit.
You can find local or online companies by searching for solar kits. Most companies will help you pick a kit or design one for you to exactly suit your needs. Shopping locally can save you big on shipping this stuff is bulky and heavy. The kits listed below are from earthtechproducts.com.
Youll find many low-priced solar shed light kits, and most of them work finefor a while. But cheap kits often fail in about a year. So check the manufacturers warranty and replacement terms before you buy, and try to find online reviews from long-term owners.
Small Solar Power Systems Can Charge Your Gadgets While Traveling
Are you drawn to the convenience of solar panels? Does the idea of taking a solar panel with you when you go camping, tailgating, or traveling to charge up all your gadgetry whenever you want appeal to you? If youve thought about buying a small solar power system but dont know exactly where to start, weve got you covered!
This article isnt about solar designed to power a house or cabin. Were also not talking about tiny solar panels that can only charge your phone when the sun is out. You know the ones those little solar panels you can clip to your backpack.
No, were talking about a solar system right in between those two. Systems that are small and portable, but have a battery and can charge your phone, run your lights, and charge your laptop indefinitely. Maybe you want to connect it to your RV or have an easy setup for your power supply while youre out tailgating.
Whatever youre going to do with your solar system, youve got a myriad of options available. You can buy premade kits that are convenient but expensive. There are semi-kits that youll need to add on to. Lastly, theres full-on DIY for the handy ones out there. We look at them all below. Take your pick!
, take a look at our article What are the Best Solar Panel Kits? For info on house-sized off-grid systems, read over The Basics of Off-Grid Solar.)
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Do You Need A Battery To Run Freezers On Solar Power
Almost everyone who runs freezers on solar panels use a battery, because without it you will not be able to use the freezer when the sun goes down.
A 50ah battery can run a 3 cu. ft. freezer for about 3 hours. To run a 5 cu. ft. freezer for 24 hours, a 150 watt solar panel and a 400ah battery are required. You can use one 400ah battery or several smaller batteries like five 80ah for instance.
In this scenario, our 5 cu. ft. freezer uses 120 watts an hour.
120 watts x 24 = 2880 watts
A 150 watt solar panel can produce 750 watts in an hour.
That means you need another 2130 watts, which a 400ah 12V battery bank can supply. 400ah is actually 4800 watts, but only half 2400 watts is usable per charge on lead acid batteries.
This solar panel and battery combo produces more power than what our 5 cu. ft. needs. But in many instances, the panel and battery may not reach 3150 watts, which is why we have added a safety margin.
Solar panel cells are sensitive to shading, and even a few leaves blocking the panel can slow production significantly. A cloud that suddenly blocks the sun has the same effect. So make sure the sky is clear when you set up a solar panel.