How to Calculate Battery Size for Inverters of Any Size
How many batteries do I need for my inverter?2021-10-12T00:21:59-07:00

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How to Calculate Battery Size for Inverters of Any Size

How many batteries do I need for my inverter?

Picking the right inverter for your needs can already be a challenge, so sizing an inverter to a battery bank can seem like daunting additional information to know. We’re here to let you know that learning how to calculate battery size for an inverter is simple. Learn how many batteries for a 3000-watt inverter or a 1kVA inverter and more, right here at The Inverter Store.

In order to size a battery bank, we take the hours needed to continuously run your inverter and multiply them by the number of watts the inverter is designed for. This equals the total watt that your inverter will pull over the time period. Finally, we divide this by the DC voltage stated by your new inverter’s product description to learn the total number of amps that should be stored in the batteries. Keep in mind that it’s best to not fully deplete the batteries when calculating this amount, so it may be necessary to purchase a larger battery in the event that the total amps approach your battery’s size.

Let’s take a look at a more concise version of the formula.

(run time in hours) * (inverter wattage) = (total watts) / (DC volts) = amps required

The formula is nice and simple, and it will work for any inverter. So, whether you’re asking how many amps a 1500w inverter draws, trying to gauge a 2000-watt inverter’s amp draw or specifically finding out how many batteries you need for a 6000-watt inverter, you can use this formula to calculate the exact measurement.

Example 1: Finding the amps necessary for a 1500-watt inverter.
Remember that first, you’ll need to calculate the total wattage pulled by the inverter over the course of its runtime, so we calculate that first: three hours of run time needed * 1500 watts = 4500 watts total. We then divide by the DC voltage of the inverter: 12 volts DC to finally get the result we’ve been looking for: 375 amps. You will need a total of 375 amps of stored power in the batteries. Remember, we don’t recommend fully depleting your batteries, so keep this in mind when you are calculating the number of batteries needed.

Example 2: How many batteries do I need to run a 2000-watt inverter and how long will they last?
Let’s say you purchase a 2000-watt inverter 12 Volt. If you max out the inverter at 2000 watts, you are pulling 2000 watts /12 volts = 166.6 DC amps per hour. If you use a 200-amp 12-volt battery, you would divide the 200-amp battery / 166.6 amps = 1.2 hours of run time. This is if you plan on fully depleting the battery, which we DON’T recommend. We recommend 50% depth of discharge. Since we recommend 50% depth of discharge, you would divide 1.2 hours /50% = .60 hours. If you use 30% depth of discharge you divide 1.2 hours/30%=.36 hours.

To find great inverters that will satisfy your power needs, please check out our full selection of power inverters made by AIMS Power. To find the best battery now that you’ve learned using our inverter battery bank calculator, shop our selection of batteries for your power inverter. If you’d like to learn how to hook up your inverter to a battery bank, we’ve explained that in a helpful guide.