9 Steps to Build a DIY Off-Grid Solar PV System – Walden Labs

Day by sidereal day the price of solar panels falls gradually. But still, installation of a complete off grid solar system is dearly-won. That ’ sulfur why I decided to write this scout on how to get all the components of your solar system individually and assemble it all by yourself .
If you have decided to install a solar control panel system to cover your home power needs, then this tutorial is for you .
I have tried my best to guide you step by dance step, from buying different components to wiring everything by yourself .
You have to know some basic electric and mathematics for designing the entire arrangement. I have besides attached links of my other instructions to make the charge control and energy meter.

For an off grid solar system you need four basic components

  1. Solar Panel (PV Panel)
  2. Charge Controller
  3. Inverter
  4. Battery

here ’ s how all the pieces fit together :
Besides the above components you need a few more things like Copper Wire, MC4 Connector, surf, meter and fuses, etc .
In the following few steps I will explain in details how you can choose the above components according to your requirement .
Note: In the pictures I have shown a big solar panel of 255W @ 24V, two batteries of 12V @ 100Ah each, 30A @ 12/24V PWM solar charge control and a 1600 VA pure sine wave inverter. But during the calculation I have taken a smaller solar system model for better reason .

Step 1: Calculate Your Load

Before choosing the components you have to calculate your office load, how much fourth dimension it will run, etc. It is very simple to calculate if you know basic mathematics .

  1. Decide what appliances (light,fan,tv etc ) you want to run and how much time (hours).
  2. See the specification chart in your appliances for power rating.
  3. Calculate the Watt Hour which is equal to the product of the power rating of your appliances and run time (hours).Load Calculation Example:Lets you want to run a 11W compact fluorescent lamp (CFL) for 5 hours from a solar panel, then the watt hour is equal to:
    Watt Hour = 11W x 5 hr = 55
  4. Calculate the total Watt Hour: Just as with the CFL we’ll now calculate the watt hour for all the appliances and add them together.Example:CFL = 11W x 5 hr = 55Fan = 50 W x 3hr = 150TV = 80W x 2hr = 160
    Total Watt Hours = 55+150+160 = 365

now the load calculation is over, next thing is to choose the right components to match your load requirement .
If you are not interested in doing the above maths then use a load calculator for this calculation. There are many such load calculators available in the internet, for example this Off Grid Load Calculator .

Step 2: Battery Selection

Batteries for Solar SystemTop view of the batteries The output from the solar panel is direct current exponent. This might is generated during day time only. so if you want to run a direct current load during sidereal day time then it seems to be identical easy. But doing this is not a well decision because…

  1. Most of the appliances need a constant rated voltage to run efficiently. Solar panel voltage is not constant, it varies according to the sun light.
  2. If you want to run the appliances during the night then it is impossible.

The above problem is solved by using a battery to store the solar power during the day and use it according to your choice. It will provide constant beginning of stable, dependable power .

Video: Battery Selection for Solar Power

There are versatile kind of batteries. cable car and bicycle batteries are designed for supplying unretentive bursts of high current and then be recharged and are not designed for a deep discharge. But the solar battery is a deep-cycle lead-acid battery that allows for overtone discharge and allows for deep boring discharge. go acid tubular batteries are arrant for a solar system .
Ni-MH batteries and Li-Ion batteries are besides used many modest power lotion .

Video: Battery Capacity and Efficiency

Note: Before going to choose the components decide your arrangement voltage, 12/24 V or 48 V. The higher the electric potential, the lesser the current and the lesser the copper loss will be in the conductor. This will besides reduce your conductor size. Most of the small home solar systems will have 12 V or 24 V .
In this project I ’ ve selected the 12 V system .

Rating of Battery:

Batteries capacity are rated in term of Ampere Hour .
Power = Voltage X Current
Watt Hour = Voltage ( Volts ) x Current ( Amperes ) ten Time ( Hours )
Battery Voltage = 12V ( as our system is 12V )
Battery capacity = Load / Voltage = 365/12 = 30.42 Ah
But batteries are not 100 % effective, assuming 80 % efficiency
Capacity = 30.42/0.8 = 38.02 Ah
By taking some margin you can select a 40Ah deep cycle contribute acid battery .

Step 3: Solar Panel Selection

255W solar panelSolar panel ratings The Solar Panel converts the sunlight into electricity as direct current ( DC ). These panels are typically categorized as mono crystalline or poly crystalline. Mono crystalline are costlier and more effective than poly crystalline panels .
solar panels are broadly rated under standard test conditions ( STC ) : irradiance of 1,000 W/m², solar spectrum of AM 1.5 and module temperature at 25°C .

Rating of Solar Panel:

The solar gore size should be selected in such way that it will charge the battery in full in one cheery day .
During the 12hr day time the sunlight is not uniform, and it besides differ according to your location on the ball. So we can assume 4 hours of effective sunlight which will generate the fink power .
therefore sum ability output of Panels = 12V x 40Ah = 480Wh
power to be generated per hour = 480 / 4 = 120W
By taking some margin you can choose a 125 W, 12v solar panel .

Step 4: Charge Controller Selection

The charge controllerAnother charge controller A solar charge accountant is a device which is placed between a solar control panel and a battery. It regulates the voltage and stream coming from your solar panels. It is used to maintain the proper charge electric potential on the batteries. As the stimulation voltage from the solar panel rises, the charge restrainer regulates the mission to the batteries preventing any over charge .
normally, the solar power systems uses 12 volt batteries, however solar panels can deliver far more electric potential than is required to charge the batteries .
By, in perfume, converting the excess voltage into amps, the charge electric potential can be kept at an optimum charge while the time required to amply charge the batteries is reduced. This allows the solar power system to operate optimally at all times .

Types of Charge Controllers:

  1. ON OFF
  2. PWM
  3. MPPT

Try to avoid the ON/OFF charge accountant as it is the least efficient .
Among the 3 bang controllers MPPT have the highest efficiency but it is besides dearly-won. So you can use either PWM or MPPT .

Rating of Charge Controller:

Since our system is rated at 12V, the consign control is besides 12V .
stream rate = Power end product 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 control. For pace by step instructions you can see my instructable on building a PWM Charge Controller .
You may besides like my new 3.0 design of an Arduino MPPT Solar Charge Controller .

Step 5: Inverter Selection

A 1600 VA pure sine wave inverter

Video: Why We Need an Inverter in a Solar PV System

solar panels ( PV ) receive the sun ’ second rays and convert them into electricity called send current ( DC ). DC is then converted into alternating stream ( AC ) through a device called an Inverter. AC electricity flows through every wall socket of your home, powering the appliances .

Inverter Types

  1. Square Wave
  2. Modified Sine Wave
  3. Pure Sine Wave

Square wave inverters are the cheapest but not desirable for all appliances. Modified Sine Wave output is besides not suitable for certain appliances, peculiarly those with capacitive and electromagnetic devices such as : a electric refrigerator, microwave oven and most kinds of motors. typically limited sine roll inverters work at lower efficiency than pure sine beckon inverters .
therefore in my opinion choose a arrant sine wave inverter .
It may be power system tie or stand entirely. In our case it is obviously stand alone and completely off-the-grid .

Rating of Inverter:

The power rate should be equal or more than the total load in watt at any instantaneous.

In our case the maximum load at any instantaneous = Tv ( 50W ) + Fan ( 80W ) + CFL ( 11W ) = 141W
By taking some margin we can choose a 200W inverter .
As our system is 12V we have to select a 12V DC to 230V/50Hz or 110V/60Hz AC pure sine wave inverter .
Note: Appliances like electric refrigerator, hair desiccant, vacuum cleaner, washing machine, etc. likely have a starting ability pulmonary tuberculosis several times greater than their normal working exponent ( typically this is caused by electric motors or capacitors in such appliances ). This should be taken into account when choosing the right size of inverter .

Step 6: Mounting the Solar Panel

After designing the solar system, buy all the components with appropriate denounce as per the previous steps .
now it is time to mount the solar panel. First choose a desirable location on the roof top, or on the footing, where there is no obstruction of sunlight .
Prepare the mounting stand: You can make it by your own or buy one. In my encase I have taken the drawing from the solar panel company and made it at a near by welding shop class. The cant of the stand is closely equal to the latitude slant of your location .
Solar panel stand I made a small wooden mount resist for my 10 Watt solar panel. I have attached the pictures, so that any one can make it easily .
Wooden solar panel stand10 watt solar panel mounted Tilting : To get the most from solar panels, you need to point them in the management that captures the maximal sun clean, i.e. south if you ’ re in the northern hemisphere or north if you ’ re in the southern hemisphere. You besides have to optimize the angle relative to the ground. Use one of these formulas to find the best angle from the horizontal at which the panel should be tilted :
If your latitude is below 25°, use the latitude times 0.87 .
If your latitude is between 25° and 50°, use the latitude, times 0.76, plus 3.1 degrees .
For more details on tilting snap hera
first, place the stand in such a way that the side is directed towards south ( or north if you ’ re in the southern hemisphere. Mark the leg stead over the roof .
To get the south / north commission use this scope android app ( or even better, a real, physical compass ! )
I decided to secure my 255W solar panel climb on my ceiling with concrete. I roughened up the surface at each leg of the stand by using a acuate aim. I made around a 1 square feet size roughly surface on the roof at each leg. This is helpful for perfecting the adhere between the roof and concrete .
Prepare concrete mix : Take cement and stones with 1:3 ratio then add water to make a thick mix. Pour concrete mix at each leg of the stand. I made a batch condition concrete mix to give maximum force .
( You can of course impregnable it into place using other methods than concrete, this is barely an model of a solution for my particular position )
Mount the panels to the stand : At the back sides the solar dialog box have inbuilt holes for mounting. Match the solar panel holes with the stand/platform holes and screw them together .
Mounting the solar panel Wire the solar panel: At the back sides of the solar panel there is a small junction box with positive and negative sign for mutual opposition. In a bombastic size solar empanel this junction corner have terminal wires with MC4 connection but for humble size panels you have to connect the junction box with external wires. Always try to use bolshevik and black cable for the convinced and negative terminal joining. If there is provision for land wire the habit a green wire for wiring this .
The junction box

Step 7: Series and Parallel Connection

After calculating the battery capacitance and solar panel rate you have to wire them. In many cases the calculate solar jury size or barrage is not promptly available in the form of a single unit in the market. so you have to add a small solar control panel or batteries to match your system prerequisite. To match the want voltage and stream rate we have to use serial and parallel connections .

1. Series Connection:

Series Connection
To wire any device in series you must connect the positive terminal of one device to the negative end of the adjacent device. The device in our sheath may be solar panel or battery .
In series connection the individual voltages of each device is additive .
Lets say 4 12V batteries are connected in series, then the combination will produce 12 + 12 + 12 + 12 = 48 volts .
In series combination the current or amperage is lapp .
sol if these devices were batteries and each battery had a rat of 12 Volts and 100 Ah then the entire value of this series circuit would be 48 Volt, 100Ah. If they were solar panels and each solar panel had a rating of 17 volts ( Osc electric potential ) and were rated at 5 amps each then the entire circuit value would be 68 volts, 5 amps .

2. Parallel Connection:

Parallel Connection In latitude connection you must connect the positive end of the foremost device to the positive terminal of the future device and negative end of the first device to the negative end of the adjacent device .
In parallel association the electric potential is stay same but the current denounce of the circuit is the sum of all the devices .
Lets say two batteries of 12v, 100Ah are connected in parallel – then the arrangement electric potential remains 12 volts but the current rate is 100 + 100 = 200Ah. similarly if two solar panels of 17V and 5 amps are connected in latitude then the system will produce 17 Volts, 10 amps .

Step 8: Inverter and Battery Stand

Battery and Inverter Stand I made the above inverter and battery stand with the avail of a carpenter. The design idea I got from this instructable. The design was in truth helpful to me .
At the binding side I made a big round hole fair behind the inverter fan for fresh air suction from the external. Later I covered the hole with credit card wire engage. A few small holes are besides made for inserting the wires from the solar jury, bang control and inverter to the battery and AC output to the appliances. At both sides 3 horizontal holes are provided for sufficient public discussion. A glass window is provided at the front side to view the different lead indications on the inverter .
Inside view In the incline flat of the inverter stand I have mounted the charge restrainer. In the future I will besides install my own DIY energy meter .

Step 9: Wiring

The inaugural part we are going to wire is the Charge Controller. At the bottomland of the Charge Controller there are 3 signs in my charge accountant. The first gear one from the leave is for the connection of the Solar Panel having positivist ( + ) and veto ( – ) signs. The second one with plus ( + ) and minus ( – ) signs is for the Battery connection and the last one for the aim DC load connection like DC lights .
Charge Controller CloseupWiring of the charge controller As per the commission restrainer manual constantly connect the Charge Controller to the Battery first because this allows the Charge Controller to get calibrated to whether it is 12V or 24V system. Connect the loss ( + ) and black ( – ) wire from the battery bank to the charge control .
notice : First connect the bootleg / negative wire from the battery to the load accountant ’ s negative terminal, then connect the incontrovertible wire .
After connecting the battery with the care restrainer you can see the Charge Controller indicator led lights up to indicate the battery level .
After connecting this, inverter terminals for battery charge is connected to corresponding positive and damaging terminals of the battery .
Inverter wiringInverter AC output immediately you have to connect the solar panel to the charge restrainer. At the back side of the Solar Panel there is a small articulation box with 2 connected wires with positivist ( + ) and negative ( – ) bless. The end wires are normally smaller in distance .
Solar Panel Junction Box Wiring To connect the cable to the charge control you need a special type of connection which is normally known as MC4 connection. See the picture below. After connecting the solar panel to the bang controller the green led indicator will light up if sunlight is present .
MC4 Connector Note: Always connect the solar Panel to the Charge Controller while facing the Panel away from the sunday or you may cover the panel with a night material to avoid sudden high voltage coming from the solar panel to the Charge Controller which may damage it .
Safety: It is important to note that we are dealing with DC current. So the positivist ( + ) is to be connected to positivist ( + ) and negative ( – ) with veto ( – ) from solar Panel to Charge Controller. If it gets mix up, the equipment can break and may catch fire. So you need to be highly careful when connecting these wires. It is recommended to use 2 discolor wires i.e. crimson color for convinced ( + ) and bootleg color for negative ( – ). If you don ’ t have red and black wire you may wrap crimson and blacken tape at the terminals .
Connect the DC load or DC light as the final examination footprint .
Additional Protection: Though charge restrainer and inverter have inbuilt fuses for protection, you can put switches and fuses in the follow places for extra protection and isolation .

  1. In between solar panel and charge controller
  2. In between charge controller and battery bank
  3. In between battery and inverter

After wiring all components the off-grid solar system is cook for use .

Metering and Data logging:

If you are matter to to know how much energy is produced by your solar dialog box or how much energy being consumed by your appliances you have to use energy meters .
DIY energy meter Besides this you can monitor the different parameters in your off grid solar system by outback data logging
For a DIY based department of energy meter you can see my instructable on building an department of energy meter which have both meter and data logging capability.

Thank you for reading my instructions !
license : CC BY-NC-SA 2.5
Like it ? Show your support on Patreon ! Let us change the earth .

source : https://www.peterswar.net
Category : Finance

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