Last Updated on 2 years by admin
You might start your DIY Solar Project from scratch or have some parts you plan to use. Assuming you have either batteries or solar panels, I will guide you with the process. When selecting batteries to match solar panels or solar panels to match batteries, you need to consider some things.
First, you need to figure out how you are planning to build the solar system.
- Are you are planning to build a system as a backup just to use when the grid power goes off?
- Are you planning to build a system to use daily?
The above option should be identified before you start building the project. And according to the requirement, you can do the calculations figure out capacity batteries and panels are needed. There are some calculations that you need to consider before going ahead.
Below you can find how to choose the right solar panel and battery
Calculate Solar Panel Watt Hours
- Solar panel watts multiply by average hours of sunlight then multiply by 75% = daily watt-hours. For example, let’s say you have 150-watt solar panels and live in a place where you get 5 hours of sunlight per day. …
- 150 watts x 5 hours x .75 = 562.5 daily Watt Hours (Wh)
- If you need to convert it to Kilo Watt Hours 562.5 / 1000 = 0.562 kWh
However, depending on the solar panels efficiency these figures could change
Calculate Battery Watt Hours
- (200mAh/1000) x 12volts x50%= 1.2Wh
- 100 Ah x 12 volts x50% = 600Wh
Example 1 – If you need to 100 Ah Battery for daily use in an area that you get 5 hours of sunlight (remember we are only using 50% of the battery to save the battery for a more extended period), you need to use a 150W Solar Panel.
Example 2 – further explaining the same.
- Watt-Hours provided by a 150W solar Panel within 5 hours of sunlight is equal to 562.5Wh (150 watts x 5 hours x .75 = 562.5Wh)
- The capacity of a 100Ah battery when 50% of its power used 600Wh (100 Ah x 12 volts x50% = 600Wh)
Both values are almost equal; therefore, you can use One 150W Solar Panel to charge a 100Ah battery. Assuming 5 hours of sunlight and 50% discharge.
Now you have an idea on how to match the solar panel and the battery. And if you went through the previous post on charger controllers. We discussed there are two types of charger controller.
PWM & MPPT. Now it’s time to link your learning from previous posts.
If the charger controller is PWM, you should select a panel with the output voltage of 18V for 12V systems and 30-36V for a 24V system. Check the charger controller specifications for more details. Even the charger controller supports a higher voltage, the extra energy gets lost during the process. Therefore, it is not recommended. But MPPT controllers support more voltage, and it creates more Ampere from the extra voltage.
I hope that the provided information is clear. Please feel free to share your technical issues through comments or Twitter.
