How Many Batteries Do You Need For A 5000W Inverter

In this article, we’ll help you discover how many batteries you need to power a 5000watt inverter. You’ll learn all the vital information about a 5000-watt inverter battery before getting one for yourself.

Let’s go!

If its a 200Ah battery, you need about 10 to support a 5000W inverter. Let me explain:

Inverters and Battery Requirements in General

You see, a lot of things need to be considered to get the perfect match between inverters and batteries. They include the following:

  • Total power requirement
  • Runtime
  • Inverter input voltage
  • Inverter efficiency
  • Battery capacity
  • Depth of discharge (DOD)
  • Lastly, number of batteries

Let’s put all this together to find out how many batteries you’ll need to power a 5000W inverter in a hypothetical scenario.

A 5000W Total Power Requirement

Yes, 5000W is a lot of power, but let’s assume the power requirements of your appliances in total equals 5000W. So, you need the inverter to supply 5000W AC power every hour.

This gives us our first parameter; Power requirement = 5000W

Example:

Secondly, let’s assume we need it to run for 10 hours. Then Runtime= 10hours

The average voltage of standard home energy systems ranges from 24V to 48V. Let’s assume 36V, so that our third parameter, Inverter input voltage = 36V

Inverter efficiency is averagely 80%. This means you actually need your battery to supply 5000W/0.8 = 6250W for one hour and 62500W for 10 hours.

Assume 200 Ah Battery

Battery capacity is measured in Ah (I.e Ampere hours). Commercially available batteries have capacities ranging from 100ah to 200ah. Let’s assume battery capacity = 200ah

The depth of discharge means how much of the battery’s capacity is used up before recharging. If you use up 30W from a battery with 100W full capacity, the battery is at 30% DOD.

You need to consider it because it’ll help you maintain your battery better, making it last longer.
Most manufacturers recommend 80% DOD or lesser. So, let’s assume DOD = 60%.

Tie Everything Together

Again, what this implies is that, although the battery has a 100W capacity for instance, you’ll only consider 60W for usage.

Now, let’s calculate the amount of batteries you’ll need for your 5000W inverter putting all these into consideration!

62500Wh / 24V = 1736Ah requirement in terms of battery capacity.

So with a battery whose capacity is 200Ah, you’ll need about 10 of those connected in series or parallel depending on the specific inverter design.

How long will a 12V battery last with a 5000 Watt inverter?

A 12V battery will last about 33minutes with a 5000Watt inverter.

We considered the inverter’s power efficiency and the amount of amp it draws.

Usually, the efficiency of an inverter ranges between 80 -90%. Assuming the efficiency to be 90%, we can say:

Power(input watt) = Power (output watt)/ efficiency

                                   =5000W/0.90

                                   =5555.55W

Account For Realistic Efficiency

A 5000W inverter with 90% efficiency will require 5500 watts of power from the battery.

Now, divide the input power with the input volts to know the inverter amp rating.

        I(Amps) = 5500W / 12V    =458.33amp

Having gotten that, if the battery is a 500AH battery and the depth of discharge is 50%, then

T(hours) = 12V × 500 AH × 0.5 / 5500 = 0.55hours = 32. 7 minutes

Thus, a 500AH 12V battery will last with a 5000-watt inverter for approximately 30 minutes

Ying Xu

Graduated from the University of Kansas with an Aerospace Engineering degree & served 4 years as an US Air Force officer. Experienced with basic survival skills, weapon system security,  technical disaster recovery, and system troubleshooting

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