With the rising popularity of solar energy systems, there is a lot of confusion about how much power a 200W solar panel can produce.
In general, a 200W can produce 6.89A for every peak sun hour.
But this still depends on the amount of sunlight available and the specs of the solar panel.
In this article, I’ll walk you step by step to calculate how much current your 200W solar panel can produce accurately.
So without further ado, let’s get started!
- Solar panels are rated by their wattage output which is the amount of power they produce for every hour of 1,000W/m² sunlight they receive
- The amount of current the solar panel produces depends on Vmp and the wattage of the panel
- A 200-watt solar panel that has a Vmp of 24.34V will produce 6.89A of current for every peak sun hour it receives
- For 5.83 peak sun hours per day, a 200W can produce 40.2Ah
- Knowing the amperage of your solar system helps you determine the size of components and appliances you can use
- A 200W solar panel with a 12V battery and Voc of 24.34V needs a charge controller of 20.8A
How Are Solar Panels Rated?
Before we get into how many amps a 200W solar panel can produce, let’s first talk about how solar panels are rated.
Solar panels are typically rated in terms of the power output in watts (W).
Manufacturers rate their solar panels under specific conditions, known as “standard test conditions” or STC.
STC includes a temperature of 25° C (77° F) and irradiance of 1,000W/m² at an air mass of 1.5.
To rate the solar panel output wattage, manufacturers direct the panels under a device that simulates the sun at an irradiance of 1,000W/m² per hour.
Then, they measure how much power the panel generates over the course of an hour.
This wattage output they come up with is the rating that you can find on the solar panel’s label.
So, a 200W solar panel means that it produces 200 Watts of power for every hour of 1,000W/m² sunshine it receives.
How Many Volts Does a 200-Watt Solar Panel Produce?
Now that we know how solar panels are rated, let’s talk about the voltage they produce.
You can see on the solar panel label two types of voltage, open circuit voltage (Voc) and maximum power point voltage (Vmp).
The Voc is the highest voltage that a solar panel can produce when there’s no current flow.
Meanwhile, Vmp is the voltage of the solar panel when it produces its maximum power output (in watts).
But in our case, we use the Vmp to calculate the number of Amps that a 200W solar panel can produce.
If you can’t read the Vmp from your solar panel’s label, then you can calculate it using this calculator.
I live in California, and based on my 200W solar panel’s specs, I selected the following parameters for the calculator:
Voc (Open Circuit Voltage): 24.34V
Number of solar panels in series: 1
Lowest expected temperature: -45°F
Voc temperature coefficient: -0.28
Based on these parameters, the calculator gave me a Vmp of 29V for my 200W solar panel.
How to Calculate the Number of Amps a 200-Watt Solar Panel Produces?
We have now gathered all the information we need to calculate how many Amps our 200W solar panel can produce.
To do this, you will use this formula:
Amps = Watts / Volts
In our example, the 200W solar panel has a Vmp of 29V.
Plugging these numbers into the formula, we get:
Amps = 200W / 29V = 6.89 Amps
So, a 200W solar panel with a Vmp of 29V can produce 6.89 Amps of every peak sun hour it receives.
To calculate the total amount of Amps a 200W solar panel can produce in a day, we need to multiply the number of peak sun hours with this 6.89A.
You can use NREL’s PV Watts Calculator and enter your location to get an estimate of the number of peak sun hours in your area.
For me, it is 5.83 peak sun hours per day with my 200W solar panel.
So, if we plug this into the formula, we can calculate that a 200W solar panel can produce:
Amps = 5.83 x 6.89A = 40.2 Amps per day
But this number will vary depending on the location you live in, and the type of solar panel you’re using.
Why Is It Important to Calculate Amps?
Simply put, amperes are the measure of electrons flowing through a circuit.
They are very important for sizing your solar system, as you need to make sure that all the components in your system are suitable for the number of Amps your solar panel will be generating.
This is especially true for batteries and inverters where you need to size them according to how much power (measured in Amps) your solar panel will produce.
For example, if you need to run a solar shed that draws 30A per day, you should use a solar panel with the capacity to produce at least 30 Amps.
Otherwise, your shed won’t get the power it needs to function properly.
What Size Charge Controller Do I Need for a 200W Solar Panel?
Connecting your solar panel directly to your batteries is not a good idea.
This is because it may lead to overcharging of your battery, which can damage it and reduce its life expectancy.
The charge controller prevents this from happening by regulating the voltage and current coming from the solar panel.
You can use this calculator to select the right size charge controller for a 200W solar panel.
For my case, I selected the following parameters for the calculator:
Solar Panel Watts: 200W
Battery Voltage: 12V
Voc of solar panel: 23.85V
Based on these parameters, the calculator gave me a result of a 20.8A charge controller.
I recommend you opt for MPPT charge controllers as they are more efficient than PWM charge controllers.
How Many Amps Does a 200W Solar Panel Produce?
A 200W solar panel produces 6.89 Amps with a Vmp of 29V per peak sun hour it receives.
How Many Batteries Can a 200-Watt Solar Panel Charge?
A solar panel can charge a 105Ah battery with 12V and 80% DoD (Depth of Discharge).
To calculate the battery size, you can use this equation:
Battery Size (Ah) = Solar Panel Daily Output (Wh) / Battery’s Voltage (12/24V) / DoD (0.5/0.75/0.8)
And since the 200W solar panel output after system losses is (200x(1-0.14)x5.83 = 1,003Wh per day), the battery size you should get is:
Battery Size (Ah) = 1,003 / 12V / 0.8 = 105Ah
How Long Will a 200W Solar Panel Take Charge of a Battery?
A 200W solar panel will take about 8 peak sun hours to fully charge a 105Ah battery with 12V and 80% DoD.
You can use this calculator to get an estimate of the time it will take for your solar panel to charge a battery.
What Size Breaker Do I Need for a 200-Watt Solar Panel?
You need a 10A breaker for a 200-Watt and 29V solar panel to ensure safe operation.
As promised, we’ve walked you through how to calculate the number of Amps a 200W solar panel can produce and why it’s important.
We’ve also provided a quick guide on how to size the charge controller and battery for your solar system, as well as some FAQs to help you out.
I hope this article has been helpful. If you still have questions, leave a comment and I’ll be happy to answer them.