The 10kWh Powerwall is one of the most popular home energy storage systems available today. In most developed countries, when all appliances are running, their daily electricity demand becomes very high, so a large capacity home battery backup system is very reliable. But most people have a common question when choosing, how many solar panels are needed to charge a 10kWh Powerwall?
Assuming a solar panel capacity of 330 to 360 watts, you will need around 10 to 14 panels to generate 15 kWh of usable energy per day. The exact number of solar panels needed to charge a 10kWh Powerwall will depend on the specific model and local sunshine conditions.
Assuming 400W solar panels are used to charge the Powerwall, the peak hours of sunlight are 5 hours per day.
The number of solar panels required is directly related to the solar irradiance and the power output of each panel.
10kWh ÷ Peak sunshine hours per day x 1000 ÷ Rated power of solar panel.
10kWh ÷ 5 hours x 1000 = 2000 ÷ 400W = 5.
A 10kWh Powerwall requires 5 solar panels.
In this article we will show you how to use this formula yourself so that you can budget your own solar build without the help of a solar calculator.
1. How many solar panels are needed for a 10kWh Powerwall battery?
Firstly, it is important that you understand that the answer to this question depends entirely on where you live and the power rating of your (required) solar panels.
Anyone who gives you an answer without this information is giving you inaccurate information.
This is why we are going to show you how to calculate how many solar panels you need for your own home, assuming you use a 10kWh Powerwall battery.
[(10kWh/peak sun hours per day)*1000]/rated power of solar panel
This formula is right here and will be your golden ticket to calculating how many solar panels you need for your home.
It will allow you to budget accordingly, so please pay close attention to the next few paragraphs where we teach you how to use it.
2. Peak sunshine hours per month
3. Solar panel power rating
First, how much electricity do you consume?
In 2020, the average residential utility customer in the US will use 10,715 kilowatt hours (kWh) of electricity per year, which averages out to about 893 kWh per month. That's about 29kWh per customer per day, so for most homes, a 10kWh Powerwall is more than enough!
Peak sun hours
Next, you need to calculate the number of peak hours of sunlight your area receives each month.
Fortunately, we have created a simple resource for Americans, Australians, South Africans and Brits to calculate the maximum daily sunshine hours in their area.
Peak sunshine hours are crucial to understanding how many solar panels are needed for a 10 kWh Powerwall. The reason for this should be easy to understand.
The more sun that shines on a solar panel, the more electricity it produces, and the same is true on the other side of the scale.
Essentially, one peak daylight hour is equivalent to 1 hour in which the sun's solar irradiance (sunlight) produces an average of 1000 watts (energy) per square metre (approximately 10.5 feet). In other words: 1 peak daylight hour = 1000 W/m² of sunlight per hour.
In this example, suppose you live in California, where there are 5.2 peak sunshine hours per day.
Rated power of solar panels
The last part of the equation depends entirely on what type of solar panel you plan to buy for your home solar installation - maybe 100W, 400W, 500W?
Most residential solar installations use 400 watt solar panels. The reason for this is that you get more power output per square foot.
So, to continue with our example to calculate how many solar panels are needed for a 10kWh Powerwall, we need to substitute the resulting data into the formula.
10kWh ÷ 5.2 x 1000 ÷ 400W = 4.8 (you can round this up to 5)
Solar panels required for 10kWh Powerwall
If you live in California, you will most likely need 5 x 400W solar panels to charge your 10kWh Powerwall.
Of course, this will vary depending on where you live and the type of solar panels you use.
For example, let's take the exact same scenario for someone living in London.
The daily peak sunshine hours in London are 2.8h
10kWh ÷ 2.8 = 3.571 x 1000 = 3571.
3571 ÷ 400W = 8.9275 (rounded up to 9)
As you can see, a home in London uses exactly the same amount of electricity as a Californian, requiring 9 solar panels instead of 5 to charge their Powerwall.
Peak sunshine hours play an important role in determining how many solar panels you need (for any situation). So, if someone continues to tell you that you will need 20 solar panels to get 1,000 kWh - they are wrong. It all depends on where you live and how much power your solar panels are rated for.
2. How much will a 10kWh Powerwall save me?
This is easy.
In order to know how much your 10kWh Powerwall will save you, you need to know how much you are paying for electricity in your country.
If you install a solar system that offsets 100% of your electricity use, you will essentially save money on your monthly electricity use.
So, for someone living in the USA, the average cost per kWh is $0.150. When installing a 10 kWh Powerwall, assuming your Powerwall discharges for 7 hours, you could save around $1.05 per day. If you use solar panels to power you during the day and use your Powerwall at night, your home could be 70% off-grid and you could save even more money!
3. Final thoughts
The most important thing to remember when calculating the number of solar panels you need for your home is the number of hours of peak sunlight your home receives and the power rating of your solar panels.
Based on the above figures, we're sure you can see (at least financially, not to mention sustainably) where a 10kWh Powerwall is worth your one-off investment, get your 10kWh Powerwall and save money on your home's electricity bill today!