To determine how many solar panels you need with our solar calculator, enter the following in their given fields:
Then click on calculate.
Say you have a solar energy system with a 12v 50Ah lithium-ion battery bank, an MPPT charge controller, and a depth of discharge of 100%. If you want your solar system to charge the batteries fully within 7 peak sun hours, your system size would be approximately 110 watts.
If you have a 12v 80Ah lead-acid battery bank with a depth of discharge of 50%. The solar system size needed to get a full charge within 8 peak sun hours when using a PWM charge controller would be approximately 130 watts.
The average peak sun hours in the United States is 5. So, in all charts, we used peak sun hours of 5.
When trying to calculate the size of the solar panels you need for your solar system, you must consider the following factors:
A battery’s depth of discharge (DOD) is a percentage indicator of how much of the total battery capacity a battery has discharged at a given time. Going by this, when a battery’s DOD is 0%, the battery is not discharged at all (fully charged). Then when the DOD is at 100%, the battery is fully discharged.
Why is your battery’s depth of discharge important when calculating solar array size? Well, with a higher level of discharge, your solar panel system will need more power to give your battery a full charge.
The battery voltage plays a part in determining how much solar power the battery needs to charge fully within peak sun hours.
For one, the solar panel voltage must at least match the battery voltage. So, since the voltage is directly proportional to power, it checks out that batteries with higher voltages need more solar power to charge within shorter peak sun hours.
Basically, the higher your battery voltage, the higher the solar array size needed.
Basically, your battery capacity affects solar array size and your preferred charging time in peak sun hours.
Different types of batteries have different charging patterns under different circumstances. So, when doing an estimate of the ideal solar panel array size for your battery bank, the solar panel calculator considers the charging pattern of the battery.
Based on the charging technique, there are two main types of charge controllers: Pulse Width Modulation (PWM) and Maximum Power Point Tracking (MPPT).
Of both options, MPPT offers higher charging efficiency than PWM charge controllers. So, an MPPT charge controller typically needs less power to fully charge your battery bank. On the flip side, a PWM may need slightly more power to charge the battery bank.
If you are going for a large solar panel system, an MPPT solar charge controller is the better option. But for a small system, you may opt for a PWM charge controller.
When choosing the charge controller for a small system, you may have to consider solar panel’s cost. If the solar panels and other fixtures are not too expensive, you may opt for an MPPT over a PWM.
The effect of charge time on solar system size is pretty straightforward. For faster charge times, you’ll need many solar panels. But if regular charge times are okay for you, you may not necessarily go for a very large solar panel size.
Basically, if your area has long peak sun hours, you can work with a moderate system size. But if your region gets a short duration of peak sun hours, you need a significantly large system size to ensure your battery bank gets a full charge within time.
Peak sun hours is the number of hours solar intensity averages 1000 watts per square meter. In other words, one peak sun hour equals 1 hour of sunlight at 1000 W/m² of solar irradiance. In other words, one peak sun hour is 1000 Wh/m² of insolation.
The intensity of the sun reaching solar panels determines how much power they generate. With higher solar intensity (solar irradiance), solar panels generate more power. But with lower intensity, they generate less.
As we’ve already demonstrated, peak sun hours are essential when trying to determine the ideal solar array size for your solar system. However, it varies from one region to another. So, how can you figure out the average peak sun hours per day in your region?
The National Renewable Energy Laboratory also offers other solar irradiance data, including monthly average solar irradiance.
You can also calculate peak sun hours yourself if you have irradiance data for your region. For instance, if the data below demonstrates the irradiance in your area between 12 pm and 5 pm:
The total irradiance between the given period would be 2900 W/m². In peak sun hours, it would be 2900/1000 = 2.9 peak sun hours. So, in your area, you’ll get around 2.9 peak sun hours between 12 pm and 5 pm.
When trying to figure out your average peak sun hours per day, work with global horizontal irradiance or global tilted irradiance.
In situations where you do not have a battery yet or do not know the ratings of your battery, you can calculate how many panels you need with the values of your average energy usage, solar panel efficiency, and peak sun hours.
For instance, say your average energy usage is 300 kWh per month, and the average peak sun hour in your region is 5 hours per day. If you are getting solar panels with 25% efficiency, your solar panel size would be as follows:
First, we’ll calculate your daily energy usage from the monthly energy usage:
Next, we’ll divide the daily energy usage by the average peak sun hours to get estimated watts of the solar array:
Estimated wattage of the array = 10/5 = 2 kW
Now, we’ll adjust the estimated wattage of the array using the efficiency of the panels:
Adjusted wattage of the array = 2 + (2 x 25%) = 2 + (2 x 0.25) = 2 + 0.5 = 2.5 kW
About 12v solar panel size calculator
As the photovoltaic (PV) industry continues to evolve, advancements in 12v solar panel size calculator have become critical to optimizing the utilization of renewable energy sources. From innovative battery technologies to intelligent energy management systems, these solutions are transforming the way we store and distribute solar-generated electricity.
When you're looking for the latest and most efficient 12v solar panel size calculator for your PV project, our website offers a comprehensive selection of cutting-edge products designed to meet your specific requirements. Whether you're a renewable energy developer, utility company, or commercial enterprise looking to reduce your carbon footprint, we have the solutions to help you harness the full potential of solar energy.
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