When we think about energy storage in power systems, we use two primary units to determine their power capabilities. These are kilowatt-hours (kWh) and amp-hours (Ah). While they are both measurements of energy, they serve different purposes entirely.
When talking about kilowatt-hours (kWh), we are referring to how much energy is being used up over time, in other words, how much energy is being drawn from the unit.
Amp-hours (Ah), on the other hand, refer to the battery's capacity and how much electrical current it’s able to deliver to the various electronics that are drawing on the battery. The relationship between them helps us understand battery performance and is essential when selecting the right battery for things like solar systems, electric vehicles, or home power solutions.
What are kWh and Ah and Why Do They Matter?
While both kilowatt-hours and amp-hours are important measurements, they are not the same. Let’s take a deeper look into how these both work and why they matter.
Kilowatt-Hour (kWh)
A kilowatt-hour is a measurement of energy; more specifically, it’s used to understand how much energy is being used over a period of time. You can think of it as a way to describe how much energy is being drawn from a source.
For example, if there is a 1,000-watt electric heater that’s been left on for 1 hour, that is 1 kWh of energy that has been consumed. Another example is a 100-watt light bulb that gets left running for 10 hours; it will also consume 1 kWh. Using this measurement, we can determine how much power is being used by the various appliances and electronics in your home.
You’ll commonly find kWh used on your utility bill, as most electricity companies use this as their unit of measurement when billing customers.
Ampere-Hour (Ah)
Ah, on the other hand, specifically refers to the capacity of a battery, or how much charge a battery can store and supply to one or more appliances. One amp-hour can be used to supply one amp of current for one hour.
For example, if you have a 10 Ah battery, that means it could provide 10 amps of current for 1 hour, or 1 amp of current for 10 hours.
It gives us a good indication of how large a battery is.
How to Convert kWh to Ah
Now you’re probably wondering, How can I use the two figures, kWh to Ah, to determine how much life I’ll get from a battery given a particular draw rate?
Let’s take a detailed look at how these two units of measurement relate and how to convert between them so you can determine how long a battery will work with a particular appliance.
The Conversion Formula
While mathematically it’s straightforward to convert kWh into Ah, it does require us to know the voltage (V) of the system that we’re working with.
Since kWh measures energy consumption and Ah measures battery capacity, the conversion between them depends on the system's voltage.
Here’s the conversion formula:
Ah = (kWh x 1000) / Voltage
Where:
kWh = kilowatt-hours (energy used).
1000 is used to convert kilowatts to watts (since 1 kW = 1000 W).
Voltage (V) is the voltage rating of the battery or system.
This works because we’re relating the energy used (kWh) to the amount of current that a system can provide (its capacity in Ah) at a given voltage.
kWh to Ah Conversion Table:
| kWh | AH @ 12V | AH @ 24V | AH @ 48V | AH @ 120V | AH @ 240V |
| 1 kWh | 83.33 Ah | 41.67 Ah | 20.83 Ah | 8.33 Ah | 4.17 Ah |
| 2 kWh | 166.67 Ah | 83.33 Ah | 41.67 Ah | 16.67 Ah | 8.33 Ah |
| 3 kWh | 250.00 Ah | 125.00 Ah | 62.50 Ah | 25.00 Ah | 12.50 Ah |
| 4 kWh | 333.33 Ah | 166.67 Ah | 83.33 Ah | 33.33 Ah | 16.67 Ah |
| 5 kWh | 416.67 Ah | 208.33 Ah | 104.17 Ah | 41.67 Ah | 20.83 Ah |
| 6 kWh | 500.00 Ah | 250.00 Ah | 125.00 Ah | 50.00 Ah | 25.00 Ah |
| 7 kWh | 583.33 Ah | 291.67 Ah | 145.83 Ah | 58.33 Ah | 29.17 Ah |
| 8 kWh | 666.67 Ah | 333.33 Ah | 166.67 Ah | 66.67 Ah | 33.33 Ah |
| 9 kWh | 750.00 Ah | 375.00 Ah | 187.50 Ah | 75.00 Ah | 37.50 Ah |
| 10 kWh | 833.33 Ah | 416.67 Ah | 208.33 Ah | 83.33 Ah | 41.67 Ah |
Amps to kWh Conversion Table:
| Amps | 12V Voltage | 24V Voltage | 48V Voltage | 120V Voltage | 240V Voltage |
| 1 Amp | 0.012 kWh | 0.024 kWh | 0.048 kWh | 0.12 kWh | 0.24 kWh |
| 2 Amps | 0.024 kWh | 0.048 kWh | 0.096 kWh | 0.24 kWh | 0.48 kWh |
| 3 Amps | 0.036 kWh | 0.072 kWh | 0.144 kWh | 0.36 kWh | 0.72 kWh |
| 4 Amps | 0.048 kWh | 0.096 kWh | 0.192 kWh | 0.48 kWh | 0.96 kWh |
| 5 Amps | 0.06 kWh | 0.12 kWh | 0.24 kWh | 0.6 kWh | 1.2 kWh |
| 6 Amps | 0.072 kWh | 0.144 kWh | 0.288 kWh | 0.72 kWh | 1.44 kWh |
| 7 Amps | 0.084 kWh | 0.168 kWh | 0.336 kWh | 0.84 kWh | 1.68 kWh |
| 8 Amps | 0.096 kWh | 0.192 kWh | 0.384 kWh | 0.96 kWh | 1.92 kWh |
| 9 Amps | 0.108 kWh | 0.216 kWh | 0.432 kWh | 1.08 kWh | 2.16 kWh |
| 10 Amps | 0.12 kWh | 0.24 kWh | 0.48 kWh | 1.2 kWh | 2.4 kWh |
Step-By-Step Conversion Guide
Now you understand the fundamental formula, let’s walk through it step-by-step using a real scenario so you can understand how the process works.
1: Determine the Energy in kWh
The first thing to think about is the amount of usage or storage you want to calculate. For example, if you want a battery to store 2 kWh of energy, that’s where you will start.
2: Identify the Voltage
Next, you must identify the voltage of the system. This, of course, will vary depending on whether your system is 12V, 24V, or 48V. Each device will have its own voltage requirement, and the combination of devices you need to power will determine the voltage of your system.
Let’s say your system is using a 12V LED light and a 5V phone charger; your system will need to be 12V to meet the needs of the LED light.
3: Apply the formula
Ah = (kWh x 1000) / Voltage
So, for a 2 kWh battery on a 12V system, the calculation would look like this:
Ah = (2 x 1000) / 12
Ah = 2000 / 12
Ah = 166.67 Ah
This means that a 2 kWh battery on a 12V system has a capacity of 166.67 amp-hours.
Make sense? Let’s apply this to a couple of real-world scenarios so you can practice it more.
12V Solar System (5 kWh Battery):
If you want a 5 kWh battery for a 12V solar system, you would use the formula:
Ah = (5 x 1000) / 12
Ah = 5000 / 12
Ah = 416.67 Ah
So, a 5 kWh battery in a 12V system would need to have a capacity of 416.67 Ah.
48V System (10 kWh Battery):
Finally, if you have a 10 kWh battery on a 48V system, the calculation would be:
Ah = (10 x 1000) / 48
Ah = 10000 / 48
Ah = 208.33 Ah
So, a 10 kWh battery in a 48V system would need to have a capacity of 208.33 Ah.
Why It Matters
Understanding how to convert kWh to Ah is essential when selecting the right battery for your power system.
Whether you’re setting up a home solar system, a home battery backup solution, or an off-grid camping system, knowing the battery capacity you require for your specific needs ensures you don’t overshoot your battery requirements or, even worse, get a battery that’s too small.
Practical Applications of kWh to Ah Conversions
In almost any situation where you’ll make use of an energy storage system, understanding how to convert kilowatt-hours (kWh) to amp-hours (Ah) is extremely valuable.
No matter what the intended use case is—whether powering an RV or designing a marine system—these conversions will help you ensure you get the correct battery capacity for your needs.
Careful planning will allow you to be efficient with your battery purchase and ensure you get the most value out of your setup.
Off-Grid Living
For most off-grid living settings, choosing the right battery capacity is critical, as you often need a capacity that can sustain you through periods when you are not able to charge.
In most scenarios, batteries are charged through means like solar panels or even wind. But energy is needed even during times when charging isn’t possible, such as still or cloudy days.
In this case, knowing how many amp-hours your battery must have to supply the required energy in kWh is essential. By calculating the Ah based on daily energy consumption, you can pick a battery solution with an appropriate storage capacity.
As an example, if you needed 5 kWh of storage per day, using our calculation, we can see a 12V system would require about 416.67 Ah to keep everything running.
RV’s and Mobile Living
RVs and other mobile living setups often have to power appliances like lights, refrigerators, and even home entertainment systems. On top of that, the batteries should also support the vehicle's electrical system. Generally, they operate on 12V, which can power most common devices.
By using the kWh to Ah conversion, you can determine how much storage is needed to ensure you have enough power to sustain yourself until you’re able to charge the batteries again.
For example, a 200Ah battery at 12V might allow you to run your appliances for a couple of days under moderate use.
Marine Systems
Marine systems, such as boats and yachts, also rely on battery power for things like lighting, navigation, and various other onboard electronic devices. Understanding the power requirements in Ah is vital to ensure you’re not left stranded at sea without enough energy to get you back to land.
Smaller boats can operate on 12V, while larger boats may need 24V. For a standard boat with a 24V system that requires 4kWh of storage, the battery capacity would need to be approximately 167 Ah.
Solar Storage Systems
Solar energy systems can’t run all the time. There will be dark, grey, and cloudy days, which means you’ll want to bank up excess power to use during those periods when the solar panels cannot sustain your needs in real time. Ultimately, this comes down to what you plan to power with your solar panels.
Once you have an idea of how much energy you’re going to consume per day, you can convert your energy needs from kWh to Ah, which will inform you of which battery size you need.
For example, if your solar system needs to store 10 kWh of energy for a 48V system, the required battery capacity would be about 208 Ah.
Solar systems can be found at 12V, 24V, or 48V; it just comes down to the size of the system. A home solar system will generally be either 24V or 48V.
Efficiency is Key
While these examples will have several variables in terms of what appliances and electronics you plan on powering, you now have a better understanding of how converting kWh to Ah can help you determine the ideal battery.
This means you won't be spending extra money on a larger battery size you’ll never fully utilize, while also ensuring you have enough juice to sustain your appliances.
Portable Power Systems: Choosing the Right Device Based on kWh and Ah Calculations
When it comes to picking the right portable power system, the right device will ultimately come down to your energy needs.
Whether your portable power system is for protection during a power outage or you're going off-grid on some outdoor adventure, you need to pick a reliable system that's going to power all your devices efficiently and reliably.
While kilowatt-hours (kWh) and amp-hours (Ah) are important in understanding a system's storage capacity, knowing how to match the right system with your power demands is key.
To make this decision easier, let's take a look at two excellent portable power stations: the Bluetti AC180 and the Bluetti AC70.
Bluetti AC180: Power for Your Adventures and Emergencies
- Capacity: 1.024 kWh (1024Wh)
- Battery Size: 85.33 Ah (12V system)
- Power Output: Multiple AC outlets, USB-C, DC carports
The Bluetti AC180 is built for those who need extended power for longer trips or home backup. With 1.024 kWh of storage, this power station can run a variety of devices, from lights and phones to small refrigerators or laptops. If you want to stay off-grid or power essential devices during a power cut, the AC180 is an excellent choice.
- Emergency Backup: Perfect for keeping essential devices powered when the grid is down.
- Off-Grid Energy: Great for powering your equipment during camping trips, RVing, or remote projects.
- Versatile Charging: Multiple outlets allow you to charge a variety of devices simultaneously.
Explore the Bluetti AC180 here.
Bluetti AC70: Compact, Yet Powerful for Everyday Needs
- Capacity: 0.716 kWh (716Wh)
- Battery Size: 59.67 Ah (12V system)
- Power Output: AC outlets, USB ports, DC carports
If you're looking for a compact, lightweight power solution, the Bluetti AC70 offers 716Wh of energy storage, making it an ideal choice for short-term power needs. Whether you're powering small electronics, lights, or a laptop, this portable system is perfect for short getaways or as a backup during emergencies.
- Perfect for Short Trips: Keep your laptop, phone, and small devices running without the bulk.
- Lightweight and Portable: Easy to carry and store, making it ideal for RVs, camping, or tailgating.
- Powerful for Its Size: Despite being compact, the AC70 can handle multiple devices at once.
Discover the Bluetti AC70 here.
Powering Up Your Knowledge: Why kWh and Ah Matter
Whether you’re powering a solar system, an RV, or a marine system, understanding the relationship between kWh and Ah ensures you select the perfect battery. This not only saves you money but guarantees reliable power when you need it most.
When you choose Bluetti, you’re getting reliable, high-quality energy storage that helps you stay powered up, whether you're off-grid or during a power outage. With products like the AC180 and AC70, Bluetti makes energy storage simple, efficient, and ready for whatever life throws at you!
