Are you trying to calculate the amount of electricity your inverter draws? Well, for that you will need a number of variables to find out.
Firstly, you will need to know the voltage of your inverter and I am assuming you already know how much watt of power your inverter bears.
If you don’t, you can just go through the manual of your inverter and check both the information.
Now, let’s get dig deeper into figuring out how much amp would an inverter draw. In this article, we will be revealing the estimated amps of inverters with different watt powers.
We will also explain why is it difficult to derive the exact amps. Go through the article, find out the section with the watt power same as your inverter, and get your answer.
How is the amp of an inverter measured?
To measure the amps of an inverter or any other electrical appliance, you will need the values of volts and watts.
Because the amperage is the number of watts per voltage. Therefore, when you have the value of both volts and watts of your inverter, all you need to do is to divide the value of watts by the value of voltage.
And thus, the result you will get from the calculation is the value of the amperage of the inverter. This formula is derived from Ohm’s law.
However, this might seem easy but it is not accurate. There are a number of other draining factors that need to be considered as well as they influence the real value of amps an inverter.
The voltage of the battery is not limited to the amount of volt mentioned in the manual. It usually provides a volt more than that.
Moreover, the peak efficiency of the inverter power is hardly 100%.
So, when the peak efficiency is measured, the overall value gets somewhat closer to the amperage value derived from Ohm’s law.
How many amps does a 100 watt inverter draw?
As I said before that only the number of watts is not enough to determine how many amps it draws. You would need the voltage of the inverter as well to measure the amps.
Usually, the inverters are of 12 volts. However, a battery of 12 volts can create up to 15 volts. And when the battery charges fully, it stores about 13.8 volts.
When the discharge is maximum, around 10 volts of the battery gets drained.
As per the direct calculation, when the power of the inverter is 100 watts and the voltage is 12, the amperage will be, 100 watts / 12 volts = 8.33 amps.
Usually, the efficiency of a 100-watt inverter is within 80% to 95%.
So, if you take about 13.8 volts, as that is what it stores when it is fully charged, and estimate the efficiency to be 80%, then the value of amps would be 8.33 amps / 0.8 = 10.4 amps approximately.
How many amps does a 300 watt inverter draw?
I am hoping by now, you have already understood that how to determine the amps of the inverter from the watt.
However, still, for your convenience, I am showing you how to find the amps drawn by a 300-watt inverter.
If your manual includes the efficiency of your inverter, then the calculation will get easier and even closer to being accurate for you.
Usually, the voltage of a 300-watt inverter is within the range of 12 volts to 14 volts. If you do not know what the voltage of your inverter is, assume that it is 12.
Then, the value of amps you will get applying Ohm’s law is 300 watt / 12 volts = 25 amps.
Here, we are only counting the voltage written in the manual. Because estimating the maximum voltage in full charge might not be completely accurate.
And it is always better to count the least variable than the highest in a calculation. However, getting back to the calculation of the amps.
Now, it is time for determining the amps calculating the efficiency. Generally, the efficiency of a 300 watt inverter is about 85%.
And if that is so, then the actual amps of the inverter will be near to, 25 amps x 0.85 = 29.4 amps approximately.
How many amps does a 500 watt inverter draw?
How many amps an inverter will draw does not only depend on its numerical values like the volts, watts, and efficiency percentage.
The number of amps an inverter draws also depends on the quality and the draining volts of the inverter.
That is no matter how accurately you calculate, the value will always be approximate.
Like all other powers of inverters, in a 500-watt inverter as well, the value of the voltage starts from 12 volts usually. So, I will also assume 12 volts here.
However, if you have the value of the voltage of your inverter, then use that value to determine the amps of your inverter to have a value more accurate as per your inverter.
Now, you know what to do. Just divide the power from the voltage and you will the amps with 100% efficiency.
That is, 500 watt / 12 volts = 41.66 amps. Now, it is time to calculate the amps with 80% efficiency. If you know the accurate efficiency of your inverter, then use that.
Here, with 80% efficiency, the amps of your inverter will be 41.66 amps / 0.8 = 52 amps approximately.
How many amps does a 600 watt inverter draw?
Again, if your inverter has a power of 600 watts, you will have to do a similar type of calculation but use a different value of watt.
In this case, also we will take 12 volts as the voltage of the inverter. Then, the amps of the inverter will be 600 watts / 12 volts = 50 amps.
This the amps of the inverter with 100% efficiency. It is hardly possible for the inverter to have 100% efficiency, so we are considering 80% efficiency.
However, do not forget to check the manual of your inverter to see whether there is actually any efficiency included.
If you see it, then use that percentage of efficiency. And if you do not, then continue with 80%. Now, the value of the amps with 80% efficiency will be 50 amps / 0.8 = 62.5 amps approximately.
How many amps does a 750 watt inverter draw?
If your inverter has a power of 750 watts, then you will need to see whether the voltage of your inverter is 12 volts, 14 volts, 24 volts, or 28 volts.
In most inverters with a power of 750 watts, the voltage of the inverter is higher than 12 volts. However, we will still count 12 volts for this calculation because that is the least value.
So, the amps of the inverter with 100% efficiency will be 750 watts / 12 volts = 62.5 amps.
Since there is the least chance for the inverter to be of 100% efficiency, we will consider 80% efficiency.
Now, the amperage will be 62.5 amps / 0.8 = 78.13 amps approximately.
How many amps does a 1000 watt inverter draw?
Now, let us how many amps a 1000 watt inverter draws. Usually, a 1000 watt inverter requires more voltage than 12 volts, or else It will last only about 34 minutes.
It depends on the type and purpose for which the inverter is being used. However, as we said we will count the least value for our calculation, we are taking 12 volts.
For 12 volts, the amperage of the inverter will be 1000 watts / 12 volts = 83.33 amps with 100% efficiency.
As you already know, an inverter hardly ever has a 100%, we will calculate its amps with 85% efficiency. Because usually, 1000 watt inverters have 85% efficiency.
So, the amps of the 1000 watt inverter with 85% efficiency will draw 83.33 amps / 0.85 = 98 amps approximately.
How many amps does a 1500 watt inverter draw?
Is your inverter with a power of 1500 watts? Then just 12 volts will not be enough for it and might lead to a voltage drop.
The voltage of a 1500 watt inverter should be at least 12.5 volts. However, I am considering 14 volts here as that should be the least voltage for a 1500 watt inverter.
Now, with 14 volts, a 1500 watt inverter will draw 1500 watt / 14 volts = 107.14 amps with an efficiency of 100%.
We are considering the acceptable percentage of efficiency to be 85%. If you know the accurate percentage of your inverter, then calculate using that.
Now, the 1500 watt 14 volts inverter with 85% efficiency will draw 107.14 amps / 0.85 = 126 amps approximately.
How many amps does a 3000 watt inverter draw?
The ideal voltage for a 3000-watt inverter is 120 volts. Even though we said that we will be counting the least value of variables, here, we are counting the ideal one.
Because if the value was 12 volts DC, then the inverter would have converted it to at least 110 volts of AC.
So, the amps of the 3000-watt inverter in 120 volts will be 3000 watt / 120 volts = 25 amps. Now, time to calculate the amps of the 3000-watt inverter with 85% efficiency.
With 85%, the amps of the 3000-watt inverter with 120 volts will be 25 amps / 0.85 = 29.4 amps approximately.
How many amps does a 4000 watt inverter draw?
In the case of 4000 watts power of an inverter, if we take 12 volts as the voltage of the inverter, then the number of amps the inverter will draw will be 4000 watts / 12 volts = 333.33 amps with 100% efficiency.
However, there is a good possibility that your inverter has a battery with a voltage of more than 12 volts. Check it and if it is so, then use that voltage of the inverter in place of 12 volts in the calculation.
Now, let’s calculate the amps of the inverter with 85% efficiency. It will be 333.33 amps / 0.85 = 392.15 amps approximately.
How many amps does a 5000 watt inverter draw?
Again, let’s see how many amps we get for a 5000-watt inverter in 12 volts. We will get 5000 watt / 12 volts = 416.66 amps.
Like all other higher power inverters, 5000-watt inverters also have a better possibility to have a battery of more than 12 volts, so check the voltage of your battery.
In 85% efficiency, it will be 416.66 amps / 0.85 = 490 amps approximately.
I hope you were able to find out the amps of your inverter with the above process. Thanks for reading till the end!
Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.
After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies.
He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.
He now shares his 20 years of expertise through his articles on the walkingsolar website.
Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.