Introduction: DIY Solar On-grid System for Your Home
After 6 months using on-grid solar system at our home, we decided to share our experiment about designing and usage. We hope this can help you to design on-grid solar system to get exact electricity amount at your location, from this calculation, you can balance between cost of system vs money from saving energy.
Step 1: Part List
Step 2: Determine Your Saving
Let's ask yourself that how much power you want solar system will cover your electric bill each month.
For example, each month your home consumes 560kWh, now you want solar system can produce electricity with amount 80% of that 560kWh. Then, solar system must produce 0.8*560=448kWh each month at your location
If you want to save more or less, just do a simple math to find how much solar system have to produce.
Of course, the larger solar system, the bigger budget you need to prepare!
Step 3: Size Solar System
Now, for example, you want solar system that can produce 448kWh each month at your location. So, what kind of solar system can meet that requirement? How to calculate?
Fortunately, we can easily to do that.
Come to web page "Global Solar Atlas"https://globalsolaratlas.info/map
At this page, choose your location, then input install direction, angle and total power (of PV panels)
Normally, the page will automatically show best direction, angle at your location in which solar will get biggest energy from sun. The only thing you need to do is adjust total power at "Installed capacity" from 1kWp (default) to 4kWp
Let's see: 4kWp system will produce 5521kWh/year ~ 460kWh/month which is near our requirement (448kWh/month). This number is acceptable for us.
If you custom the requirement each month, then adjust "Installed capacity" until total producing power meet your custom requirement.
Step 4: Choose Equipment
After finding out total solar sytem you need, then move to step choosing equipment.
Two important part is PV panel and on-grid inverter.
You can choose any PV panel, but need to care about: Power each panel, efficiency, Square -> those factor will effect to square installation.
Our real system: total power is 2.9kWp -> use PV panel from Panasonic 290W/ Panel -> need 10 panels -> need 16.3m2 square of proof.
If your proof have enough space for all panels, then it is no problem.
On-grid inverter should have ability to support all of installed PV panels.
Our real system: on-grid inverter is 3.3kW -> enough to support 10 PV panels (2.9kWp)
In addition, you need to focus on efficiency of inverter, wifi support (for easily checking producing power via local webpage)
Step 5: Installation
The most important part of installation is direction and angle of installation PV panels
For example, our system is 4kWp at direction South at angle 12dg will produce 5,517kWh/year
However, same system 4kWp but at direction West at angle 38dg will prodcue 4,644kWh/year -> reduce about 900kWh/year!
Because of your proof direction and angle sometimes will not meet best installation direction/ angle for solar system, base on tool at "Gobal solar atlas" page, you can know exactly how much power will be reduced if not installed in best direciton/ angle.
Our real system: install at West direction, 38 degree angle, then 2.9kWp system will produce 3338kWh/year -> 9.14kWh/day
After clear about direction and angle, then move to process of installation. You might need 2 manpower to install all PV panel on proof.
RISK! Serial connection of all PV panel can make 400VDC can damage your life!
Base on connection diagram on picture, make circuit for system.
Step 6: Declare On-grid System With Your Government
On-grid system will merge power from solar system with Nation grid line.
Basically, after installation, you can turn on on-grid inverter to start using solar system along with grid system.
However, we need to declare (or make contract with Government/ Nation Power Agency) to sell remain producing power from your solar system. Why you need to sell remain power for them?
During day time, on-grid system will producing power which you will never can use all of them at that time, so remain power from solar will be "pushed" into grid line, then the power meter (2-way, not 1-way as usual) will record amount of power that "pushed" to grid line. This power meter also record how much power you use from grid line
Finally, your electricity bill = [total power usage from grid line] - [total power from solar "pushed' to grid line]
Step 7: Maintenance and Usage
Compare to 6 months usage, we found that each day 2.9kWp system produce 9.57kWh/day -> same with estimated calculation by Global Solar Atlas page: 9.14kWh/day
Our real system produces more power slighly because those 6 months is in Sunny season, in rainy season, producing power will be reduced! So, in average, system can create about 9kWh/day!
Normally, you don't need to do any maintenance for system except clean the PV Panel to get rid of dust which can reduce power producing.
Sometimes, you can access to local webpage via wifi to see how much power they producing.
That's it! I hope i make it easy for you.
If you have any comment, please leave here. Thank you :)