Ultimate guide: DIY solar system kit
- 04 Oct 2020
- 8 min
There are two ways to switch your house to solar energy. One is to hire an installer and get a turnkey solution. The other is to compose a PV system yourself which is going to be cheaper and more engaging. Here is our ultimate guide on how to get a DIY home solar system in just five steps.
Step 1. Сalculate your energy needs
To become truly energy independent with a DIY solar system for home you need to assess the amount of energy it will have to produce. Depending on your circumstances, the best approach will be one of the following.
Checking past utility bills is the most rational and time efficient. They will tell you the average energy consumption per month, which you just need to divide by 30 days.
the average electricity consumption for a US homeowner
You can expect some seasonal change in the numbers, especially if the climate in your area differs throughout the year. Some shifts in consumption patterns are also inevitable. We recommend using the highest monthly bill as a baseline, because it can give you additional safety margin.
Checking the power ratings is for those who don’t get bills. Make a list of all the devices you use daily, find out their power ratings and multiply by the time you normally use them a day. Sum everything up to get your average energy consumption. Sounds doable for an RV solar installation or a marine power system: the power consumption there is more or less predictable. When it comes to a house, the task becomes herculean.
Don’t forget to account for a 20-30% energy loss. It’s inevitable due to multiple reasons: shading, high temperatures, reflection, dust and more.
Step 2. Choose the type of your system
There are three types of solar power systems: grid-tie, off-grid and hybrid. A grid-tie system allows you to sell excess electricity to the grid and therefore become a prosumer. On the other hand, an off-grid solar panel system can make you fully independent. A hybrid system can do both, hence the name.
90-95% of solar systems in the US are connected to grid
You don’t have to embrace one or the other right off the bat. Personal experience is an important factor and you always have the possibility to upgrade. Grid-tie solar system design requires two main elements – solar panels and an inverter. If you decide to go off-grid, you’ll need a battery and a charge controller.
Step 3. Size your PV system
The production of your future system depends on how sunny the place is. After figuring the right number and wattage of your panels, you’ll also have to make sure other components will fit into your DIY solar system kit.
Size the PV modules
Divide your daily energy consumption from Step 2 by the number of peak sun hours in your area. You can find them in our State Solar Power Rankings.
Let’s take a house in New York that consumes the average 29.2 kWh per day. With 4.2 peak sun hours in NYC, the family will need a solar panel system with a capacity of
29.2 kWh ÷ 4.2 h = 7 kW
Such a system could consist of twenty 350 watt panels or eighteen 400 watt panels. The family may opt for panels of higher or lower wattage, depending on the available yard or roof space.
Size the inverter
An inverter is used to convert direct current into alternating current, which is needed to run most appliances. The size of your inverter should match or exceed the DC rating of your solar PV system.
For a 7 kW system, an inverter with a nameplate rating above 7,000 watts will be a perfect match. You can also opt for microinverters, which are installed right on solar panels. Their size should correspond to the power output of a particular PV module rather than the whole system.
Inverter manufacturers usually specify sizing guidelines for their inverters in product specification sheets. When you know the DC rating of your setup, just make sure that recommended maximum DC power of a specific inverter is slightly higher. If the power output of the solar modules paired with the inverter don’t meet the stated guidelines, it may void the warranty.
Size the batteries
Decide how many days’ worth of energy you want to store in your battery bank. The product of the number of days and watt-hours required per each day is the storage capacity you need.
It you use lead-acid batteries, multiply the result by 2, since their recommended depth of discharge (DOD) is about 50%. To convert the result in kWh into amp hours (Ah), divide it by the battery voltage. Lithium-ion batteries has a 80-95% DOD.
Let’s go back to the NY family. They want the battery bank to last one full day. As they consume the average of 29.2 kWh per day, it is the capacity they need. No battery should be discharged all the way to zero, so they add from 20% to 50%, depending on the type of batteries they choose.
29.2 kWh + 20% = 35 kWh (lithium-ion)
29.2 kWh + 50% = 58.8 kWh (lead acid)
This is the energy the batteries will have to provide. Thus, five 7.5 kWh (48 V) lithium-ion batteries can satisfy the needs of the family. If you go for bulkier, less energy dense lead acid ones, you will need twenty eight 2.1 kWh cells (12 V).
Size the charge controller
Take the wattage of your PV system and divide it by the voltage of your battery bank. Add 25% to allow for cold temperatures and round up to the tenth. A 7 kW system and a 48 V battery bank require a 40 A charge controller, as
7,000 ÷ 48 + 25% = 37 A
Step 4. Go shopping
The steps that involve counting are over. It’s time to begin the most exciting part – purchasing your solar equipment. A1SolarStore supplies all the necessary items for residential and commercial PV systems, making it possible to find everything in one place.
A1SolarStore has a variety of inverters ready for use in both grid-tie and off-grid systems. Some of Solaredge models are of the right size and offer additional functionality, such as monitoring and datalogging, specialised online and mobile platforms.
We offer batteries as well and you can check what models are in stock. Whenever you add a battery to your solar system, get a charge controller! It will prolong the lifetime of your energy storage and pay off in the long run.
Step 5. Installation
It is the final step but not necessarily the one you want to make on your own. The number of panels, type of roofing or terrain and relevant experience are all things to consider before going down the DIY road. It may be quite tricky and the solar equipment is much more expensive and complicated than furniture from IKEA.
average weight of a solar panel
Solar panels weigh a lot for a single human. Without a pair of additional hands, hiring professional installers is the only way out. Unless we are talking about an off-grid system, you will need to contact a professional anyway. Only a certified specialist can connect your system to the utility grid.
However, if the site isn’t difficult and you are not alone, we have a number of articles dedicated to DIY installation. They are worth reading without skipping lines, because the installation process does not admit mistakes.
These five steps can help you make your DIY home solar system from scratch. Little time is needed to assess your energy needs. You can use A1SolarStore calculator to help you with math. Remember than there is no need to choose the system type straight away. You can start small and then upgrade from a DIY grid-tie solar system to a hybriud or grid-tie one. The experience you gain will allow you to make wiser decisions.
A1SolarStore team is always ready to help you out at any point of your journey to a new solar life. Per Aspera Ad Sol!
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