How Many Amps Does a 600 Watt Inverter Draw?

A 600W inverter is ideal if you need a portable system that is affordable and practical to carry. Although it has its limits, a 600W inverter can run small and medium sized appliances, camping and travel gear. But how many amps does it draw?

A 600W inverter draws 5 amps at 120V, 5.4 amps at 110V and 50 amps running from a 12V battery. Divide the inverter watt load by the voltage and you get the amps drawn per hour.

How to Calculate 600 Watt Inverter Amp Draw

Inverter amp draw is based on the load, not the capacity. A 600W inverter with a 300W power load will pull amps based on its 300W load, not the 600W capacity.

The formula is watts / volts = amps

If the inverter is running a full load (600W) off a 110V power source, it draws 5.4 amps.

600 / 110 = 5.4

The same inverter running off 120V but with a 300W load draws 2.5 amps.

300 / 120 = 2.5

If you are off the grid, the amp draw will depend on the battery voltage.

A fully loaded 600W inverter powered by a 12V battery bank pulls out 50 amps an hour.

600 / 12 = 50

A 24V battery draws half the amps a 12V does, so this same inverter and load only pulls 25 amps.

600 / 24 = 25

These calculations are for general guidelines only. Inverter efficiency, appliance design, environment and other factors affect power consumption and may lead to higher usage. The Giandel 600W Power Inverter has a high efficiency rating so you get more value for your money.

We will look at inverter efficiency shortly, but bear in mind that appliance power consumption has the biggest effect. Modern appliances are more energy efficient so they are more suitable for inverters and solar power systems.

Energy Star appliances use less power than older models. A modern blender might consume 400 watts an hour, well within the inverter capacity. But older, non energy efficient models may need twice that power.

How Inverter Efficiency Affects Power Consumption

If you notice that your inverter seems to use power when it is not connected to anything, that’s because the system does. Inverters in standby mode consume a bit of power, just like a TV on standby.

The power use isn’t that large though. A bigger concern is the inverter conversion efficiency. You will see inverters rated at 90%, 93% and so on, which indicates how much energy is kept when DC is converted into AC.

A 93% efficient 600W inverter with a full load uses 642 watts. Why? because 7% energy is lost. Which also means the inverter uses an additional 7% power consumption:

600 x 107% = 642

If the inverter was 85% efficient, a fully loaded 600W inverter will cost 690 watts.

600 115% = 690

That is almost 100 additional watts used by the system due to inefficiency. That is why it is so important that you buy the most efficient inverter possible.

The larger the inverter the more important efficiency is. Even with a relatively small 600W system you should always look for high efficiency.

You can choose between pure sine and modified sine wave inverters. Pure sine wave do a better job of converting and preventing energy loss. But they are also more expensive.

Modified sine wave inverters are more affordable but not as efficient. For large inverters that will run sensitive appliances and electronics, pure sine wave is ideal. But modified sine wave will do for small loads.

What Can a 600 Watt Inverter Run?

Inverter capacity is measured two ways, running and surge watts. Most of the time the labeled capacity refers to running watts. The surge watts is usually twice that, so for a 600W inverter the surge peak is 1200 watts.

A 600 watt inverter can be used for TVs, laptops, fans, blenders, lights and small to medium sized appliances. You can run a 250W drill, though other power tools need a bigger inverter.

A 600W inverter is too small to run the average kitchen refrigerator. However it should be able to run a 12V camping fridge.

A fully loaded inverter draws 50A an hour from a 12V battery. A typical camping fridge pulls 5 amps so it should last for 10 hours or so. You can use this inverter to power other appliances as long as they are less than 600 watts.

Remember that the 1200 watt surge capacity is only good for a few seconds. If you have a 600 watt load that needs 1200 watts to start, the inverter can handle it.

But the running watts must still be under 600 watts. This surge peak cannot be more than a few moments as it could cause overloading.

How Long Will a 600 Wat Inverter Last?

An inverter is going to keep running as long as there is power. If you are on the grid, the inverter will only stop if electricity is lost. Other than a power outage or damage, there are no issues.

If you are off the grid, the inverter will probably be connected to a battery bank. The battery bank size determines how long an inverter can power its load.

The longer you want to use the inverter load, the larger the battery bank needs to be. And you should also have some battery reserve power so you can keep the load running while the other batteries are recharging.

How Many Batteries Do I Need For a 600 Watt Inverter?

We have already explained that inverters can run indefinitely on the grid. But for off grid systems, you need to make sure the battery size is commensurate to your power requirements.

A 12V 100ah battery can run a fully loaded 600 watt inverter in just under two hours. 600 watts equals 50 amps (W / V = A). The load draws 50 amps an hour so it should last two hours. But due to inverter efficiency, it will be less than that.

Using this as a guide, you can get a fairly good estimate how many batteries are required to run an inverter load.

Inverter load x runtime / battery voltage = minimum battery amps needed

So if you want to use a 600 watt load for 4 hours, decide if you will use a 12V or 24V battery. The same calculations apply for either one. Let us try 12V:

600 x 4 = 2400

2400 / 12 = 200

Example, the Renogy 200ah 12V AGM battery can run a 600W inverter load for four hours. But again this will be just under that due to inefficiency. If you want to run the load for a full four hours, you need more than 200ah, preferably 225-250ah to offset the inefficiency.

With a 24V battery you only need 100ah to use the load for the same period. The calculations show us why:

600 x 4 = 2400

2400 / 24 = 100

The higher the battery voltage, the higher its wattage capacity. Loads running off a 24V battery also draw less amps.

In this case a 24V battery seems more practical. But if you only have 12V available, you can connect them in a series to get 24V.

Is a 600W Inverter Enough?

This is going to depend on how you use it. The information above should give you an idea of what this inverter can and cannot do.

A 600W portable inverter is ideal for portable use. If you are going to spend the weekend boondocking in your RV, this inverter should be enough. Note that these 600 watts should be used for your appliances and devices. The solar power needs of your RV are a different matter and should also be calculated.

600 watts is probably too small even for a small house. At best you can use this as an emergency backup power to run essential appliances. The inverter is large enough to run a 12V fridge, TV, lights and other appliances.

But if you want access to a kitchen sized refrigerator, toaster and other appliances, a larger inverter is required. How big of an inverter depends on how many watts you will load and for how long.

Conclusion

If you want to buy a 600W inverter, check the customer feedback. Not all 600W units are built the same way, with some more efficient than others. Doing a bit of research will go far in helping you decide what to buy.