What Happens When a Power Inverter Overloads?

Power inverters are a great tool to have around. There are so many uses for them ranging from vehicles, motorhomes, camping, tailgating, and even living off-grid. Whatever your reason is for using a power inverter a common question that we receive on them is what exactly happens when the inverter is overloaded? Now, ideally, you do not come into this situation. In a perfect world the inverter you have purchased is rated enough to handle the wattage of all of your needs. But, in the off chance that you are approaching the wattage limit of your inverter what will happen if and when you do exceed the rated wattage?

The results of exceeding your inverter’s wattage will be one of two things and it depends if your inverter has a surge protector. If it does NOT then your inverter will keep running in an attempt to provide the required power. If left unchecked this will damage and perhaps permanently destroy your power inverter. Be sure to spend a bit more money and get an inverter with a surge protector. It is the smart choice here.

If the inverter DOES have surge protection then the inverter will simply not turn on due to the higher wattage demands. The inverter will try again after a few seconds to see if the load has changed. If it has not, it will shut off. This process will repeat a number of times until the inverter finally shuts off for good. If you wish to restart the inverter after this point you will need to do so manually using the control panel on the inverter.

Most inverters can actually handle a load LARGER then what they are rated for, but only for a small amount of time. As an example, you may be able to get thirty-five hundred watts out of your three-thousand watt inverter but it would only last for a half-hour or so until the inverter shuts down. Each inverter is different though and it is best to check your owner’s manual to see how much and how long of an overload your inverter can take.

This point brings me to the topic of starting watts versus running watts. Most of us are all familiar with the concept of running watts. This is a measurement of how much power your appliance or electronic uses while running. Sometimes the appliance is labeled with wattage use, but other times they are not. If not you can still determine the watts by finding the total amperage draw of the appliance. When you have the amperage number multiply it by the volts which is going to be your standard one-hundred and twenty volt plug-in. So, as an example say you have a five amp coffee maker that plugs into a one-hundred and twenty volt outlet. Five amps times one-hundred and twenty equals out to six-hundred watts. This is the running watt number of the coffee machine.

The concept of starting watts is where it can get a bit tricky. Depending on the appliance you wish to power some of them may require an extra boost of power for them to initially startup. An example of this would be a refrigerator. Refrigerators come with a compressor that starts the refrigeration process. This compressor needs an extra boost of power just to get turned on and started. After a short amount of time, say thirty seconds or so, the starting watts are no longer needed and the refrigerator transitions to a smaller running wattage number.

Because of starting watts many folks have to purchase a power inverter with a higher wattage then they anticipated. There is some good news though when it comes to starting watts. Depending on your inverter you may be able to get away with running an appliance that has a higher starting watt number then your power inverter. Starting watts are only required for a short amount of time and if your inverter can handle the overload for that thirty seconds or so then you should be fine to run said appliance. Be sure to check your inverter’s manual before purchasing so that you know for sure.


In short folks, it really depends on what type of inverter that you have. Do you have surge protection or not? My advice is to purchase an inverter that exceeds your power needs by at least twenty or thirty percent. Factor in your starting watts into this number as well. So, you should exceed twenty or thirty percent ABOVE your starting watts. This is needed so that if you miscalculate a wattage requirement OR if you wish to add something additional down the road you are not at the peak of your inverter’s wattage. The twenty to thirty percent gives you a buffer and helps to prevent an overload.

Thanks for reading and I hope this article was helpful,

Alec Johnson

You may also like