How Many Batteries Do I Need for a 10KW Solar System: a Full Guide -
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How Many Batteries Do I Need for a 10 KW Solar System?

Short on Time? Here’s The Article Summary

The article discusses the considerations for determining the number of batteries needed for a 10 kW solar system. It explains how solar panels convert sunlight into electricity and the role of batteries in storing excess energy for later use. The calculation for battery needs involves dividing the daily solar power system output by the battery voltage.

It also highlights the importance of not fully discharging batteries to maintain their lifespan. Additionally, the article provides information on the power produced by a 10 kW solar system, the cost of such a system, and the benefits of deep cycle solar batteries for storing solar energy effectively.


If you’re wondering how many batteries you need for your 10 kW solar system, you’ve come to the right place. 

Solar panels are a great investment for your home. They’re an eco-friendly power supply that can ultimately take your home off the grid, but you need to hook them up to enough batteries to store the power they absorb from the sun.

So, how exactly does a solar system work? Read below to find out more about this and how to determine how many batteries you need for your 10 kW solar system.

How Does a Solar System Work?

Solar panels use photovoltaic (PV) cells. These are solar cells that convert the sun’s energy into electricity.

how many batteries for 1kw solar system

The cells contain semiconductor metals and they generate electricity when sunlight hits them. This is why you ideally need more than one solar panel. The larger the surface area you have covered with panels, the more PV cells you have collecting the sun’s energy.

It all equates to a lower energy bill. 

Solar panels produce direct current (DC). However, common household appliances don’t use DC. This is why we need to connect our solar panels to an inverter. Inverters change the current to alternating current (AC). 

Your solar system might produce more power than your inverter can store, though. This is great, but only if you can store and use that power later. 

This is where batteries come in. They store the excess power, which you can access when the sun isn’t shining.

Switching to solar is a great investment despite the startup costs. You need to fund the solar panels, inverter, batteries, and installation, but you’ll reap the rewards. Over time, the entire setup will pay for itself. Eventually, you’ll be getting your power free of charge.

How to Calculate Your Battery Needs

When calculating your battery needs, you need to know how units of electricity work. It’s measured in Watts, and one unit of electricity is 100 Watts, which is commonly referred to as a kilowatt, or kW. 

how many batteries for 1 kw solar system

A kilowatt-hour is a unit of energy. Contrary to popular belief, it’s not the usage of kilowatts per hour. It’s actually the amount of energy needed to run a 1,000W (1 kW) appliance for an hour. 

To calculate your battery needs, you need to know how many units of electricity your solar power system is producing. This varies depending on how many solar panels you have installed, as well as how much of the produced power your household is actively consuming.

This is because you only need to store what you’re not using immediately.

There’s a formula you can use to decide how many batteries you need for your 10 kW solar system. 

Here it is:

Take your daily solar power system output and divide it by the battery voltage (of your battery of choice). This tells you how many of those batteries you need to store the energy your solar system generates.

Backup Power Calculation

As we mentioned, calculating your battery needs can be tricky. Here’s another simple formula you might find helpful:

Total solar power generation / the voltage of the battery = the battery amps you require.

how many batteries for 10 kw solar system

Let’s put that into practice. If your solar power system generates 40 kW of electricity in a day, that’s 40,000 Watts. Divide this by the voltage of the battery you have on hand, or the brand you’d like to buy. 

The most practical battery for solar power systems is a 48V battery, so we’ll use that as an example. Here’s how to calculate the battery capacity for your solar system.

The calculation looks like this:

40,000W / 48V = 833.3 amps.

You’d then need a 48V battery with 833.3 amps, or a combination of batteries that make up that voltage. For example, if your 48V battery is only 300 amps, you’d need three of those. If your battery is only 200 amps, you’d need four of those. 

Battery Capacity and Discharge Rate

It’s important to understand that batteries weren’t made to be continuously depleted. This affects their lifespan. Adding batteries to your existing solar power system is a great investment, but it’s important to understand how batteries work before doing so.

Battery discharge refers to the process of your battery losing—discharging—energy over time. Most people don’t know that batteries are discharging voltage whenever they are not being charged; not only when you’re using them to power various items.

If you use all the energy in your batteries, you’ll fully discharge them. They should never be fully discharged - in fact, the only batteries that can be fully discharged are lithium-ion batteries. This is the type of battery that powers your smartphone.

As a general rule, you should never use your batteries beyond half of their capacity. This affects how well they can store power, and if you continuously allow it to get to this point, you’ll eventually need to double your battery capacity to be able to store the power generated by your solar system.

If you consistently consume less than what your solar system generates, it’s possible to use the system without batteries at all. It’s best to only buy the batteries when you need them.

How Much Power Does a 10 KW Solar System Produce?

how many batteries for 10kw solar system

The amount of power produced by your solar system depends entirely on how much sun it gets during the day. If we work on the assumption that it gets around 5 hours of sunlight per day, it should produce 30 to 40 kW of power per day. This equates to around 1,000 kW per month.

Is My 10 kW Solar System Enough to Power My House?

The typical American home has a usage of around 900 kW per month. A 10 kW system should be enough then, considering it creates around 1,000 kW of electricity per month.

In some states, your solar system might not generate as much electricity simply because that state doesn’t get as much sunshine.

There are some points you can consider before investing in a 10 kW solar power system. Here they are:

  • Check your monthly energy consumption on your monthly bill, and average it out over a 12-month period.
  • Check how many hours of sun you can realistically expect in your area.
  • Compare a few 10 kW solar power kits - you can browse our high-quality, well-priced kits on our website.
  • Calculate the number of batteries you’ll need to store the energy generated by your kit. Many people forget this last step, and can’t store energy for rainy days.
how many batteries do i need for a 10 kw solar system

If you feel you have very specific needs that a generic solar power kit can’t meet, you’re welcome to contact us for a custom solar kit. Our goal is always to equip you at best as possible so that you can access sustainable and affordable power.

One of our top tips is that the size of your house has no bearing on how much power you consume. What matters is the number of appliances you need to run.

So a small house with a lot of appliances will likely have the same energy usage as a large house with only a few appliances in it. This is why we suggest taking a look at your average power consumption over a 12-month period before deciding how much solar to invest in.

How Much Does a 10 kW Solar System Cost?

10 kW Solar system kits can cost anything up to $35,000 - but don’t worry, ours cost around $20,000.

We have convenient kits available for you. These take into account everything you need so that you can make one purchase. The bonus here is that you don’t have to go through the labor of sourcing and comparing prices for each item in the kit, and you can rest assured that ours are priced competitively. 

Solar power kits contain the following:

  • A number of solar panels
  • Hardware for racking and mountain your panels
  • A system monitor, that you can monitor the energy produced by your system
  • An inverter.

Batteries aren’t generally part of stock-standard kits, because there are so many options for you to choose from. We can include batteries in a custom kit for you, or you can choose one of our deep cycle solar batteries


how many batteries for 10 kw solar systems

What Is a Deep Cycle Solar Battery?

Deep cycle solar batteries are one of the most important purchases you’re going to make when going off-grid.

We’re not going to go into too much technical detail; we know you don’t have all day here. Our goal is to make the transition to solar less painful for you.

Basically, deep cycle batteries allow you to store clean energy more effectively. You can run them a little lower more often, so you don’t spend too much time worrying about depleting your batteries and having to replace them.

They make your solar system accessible after the sun’s gone down, as they allow you to store this power. This is why you should get a battery for your solar system.

These batteries are slightly pricier, but we think this cost to add backup power to your solar system is worth it. After all, you won’t be sitting around waiting for your batteries to suddenly stop working, and having to replace them.

Some of the best deep cycle batteries come with a 3,500 battery cycle guarantee, meaning you can deplete the battery that many times. There are also numerous plug-and-play batteries, and we love these.

They take the complexity out of solar systems and make them accessible to everyone. A great example of this is the Lion Energy Safari UT 1300 battery, which you can access on our store. This is one of the best deep cycle batteries for your solar system.

It’s water-resistant, stackable, and comes with a lifetime warranty. It’s also got an impressive capacity, so it’s able to keep you going for a while. It’s one of the best batteries for an RV system.

The Ultimate Solar + Storage Blueprint (Mini Course)

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Join 15,000+ solar enthusiasts breaking free from their energy dependence with this short step-by-step video course that will make you a solar + storage expert. Start your journey to energy independence today.

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Article by

Alex S

Alex is a co-founder of Shop Solar, a company that he established in 2018 to revolutionize the solar industry by simplifying the process and making it more simple and cost-effective. Under his strategic leadership, Shop Solar has grown into a comprehensive one-stop-shop, empowering over 40,000+ customers to access top-quality solar and storage solutions, comprehensive information, intuitive tools, and professional installation services.

With a passion for innovation and sustainable energy, Alex has successfully expanded the business's reach and impact, serving as a driving force in the company's growth and development. You can browse best seller's here.

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