How Many Batteries for a 2000 watt Inverter?

You are here because you want to know how many batteries you need to run a 2,000W inverter.

At the end of this article, you will know exactly how many batteries you need and which configuration (with diagrams).

Let me explain.

Battery Voltage

The first we need to know is what battery voltage you will use.

• 12V
• 24V
• 48V

Here are the advantages of a higher battery voltage:

• less current, meaning cheaper wires
• More efficient conversion in the whole system
• Less voltage drop

Limiting System Current

If we build a DIY system, I recommend limiting the current to 100A. This is because of safety reasons of a DIY installation and it will save you money. Here are the recommended battery voltages with corresponding inverter sizes:

• 12V battery: Max 1,200W inverter
• 24V battery: Max 2,400W inverter
• 48V battery: Max 5,000W inverter
• More inverter capacity: inverters in parallel

Battery Capacity and C-rate

Now that you know you should use 24V battery to run a 2,000W inverter, we can take a look at the capacity and the C-rate.

The capacity of the battery is indicated in amp hours or simply Ah. The most common battery will be 12V and 100Ah.

The battery capacity ties in directly with the C-rate of the battery. The C-rate indicates how fast we can charge and discharge a given battery. There are two kinds of batteries we tend to work with. These are:

• Lead-acid
• Lithium (LiFePO4)

Both of these have a different C-rate.

• Lead-acid: recommended C-rate of 0.2
• Lithium: recommended C-rate of 0.5 to 1

Let’s use an example of a 12V 100Ah lithium battery (0.5C). If we multiply the battery capacity with the C-rate, we can see that this battery can deliver a current 50A.

100Ah x 0.5C = 50A

If you want to learn more about C-rate, watch my video about it here

Now if we want to figure out how much power (watts) this battery can deliver, we need to multiply the recommended C-rate by the battery voltage:

50A x 12V = 600W

Now you can see we can only have a 600W inverter with a 12V 100Ah lithium battery.

Now that we know how the math works, we can use these calculations on a 2,000W inverter.

Don’t know which inverter to get? Check out my article about the best off grid inverters.

How many batteries do I need for a 2000 watt inverter?

We will split this section up in two parts. one for Lead-acid batteries and one for lithium (LiFePO4) batteries.

How many Lead-acid batteries for a 2,000W inverter?

If we divide 2000W by 12V we become 166A. This is too much for a DIY system, so we will use a 24V system.

2,000W / 24V = 83A

We can see that 83A is perfect (100A fuse), and the wiring will need to be half as thick as if we were to use a 12V system.

Now the C-rate of lead acid is 0.2C. This means that we need a high capacity battery for this to work.

Disclaimer: having a low battery capacity will still work, but the lifetime of the batteries will suffer. Therefore, we need to size according to these values.

83A / 0.2C = 415Ah

We can see that we need a 24V battery with a capacity of 415Ah. This means we need:

• 8 pcs 12V 100Ah lead-acid battery

Or

• 4 pcs 12V 200Ah lead-acid battery

Or

• 2 pcs 24V 200Ah lead-acid battery

Here are the wiring diagrams for these battery systems:

How many Lithium batteries for a 2,000W inverter?

The first calculation will be the same as the lead-acid battery. We will still use a 24V battery system.

2,000W / 24V = 83A

The c-rate of a typical lithium (LiFePO4) battery is 0.5C.

83A / 0.5C= 166Ah

So our 24V battery needs a capacity of 166Ah to work efficiently. We need the following batteries:

• 4 pcs 12V 100Ah lithium battery

OR

• 2 pcs 12V 200Ah lithium battery

OR

• 1 pc 24V 200Ah lithium battery

Here are the diagrams for these configurations:

Conclusion

We can see that we need fewer lithium batteries than lead-acid batteries. This is because the C-rate with lithium is higher.

We need a 24V system if we want to run a 2,000W efficiently.

If we have a lead-acid battery we need a total battery of 24V 400Ah

If we have a Lithium battery, we need a total battery of 24V 200Ah

Would you rather use a 3000W inverter? Read my article about it here.

Nick

I’m an off-grid enthusiast. I created this website to give clear and straight-to-the-point advice about solar power. I’m also the author of the book ‘Off-grid solar power simplified‘. Read more about me on my about page, check out my Youtube channel, or send me a message.