How to properly size power inverter for camping or home scenario?

The first step is to make a big list of all the appliances that you have and that you would like to be powered up by your inverter. Please write all the relevant information, such as the power consumption. Some people want to take a bit of shortcut, they look at their power description board and think all these light bulbs or all the kitchen appliances are being provided with power through a breaker which is rated for example 15 Amps. They just write down the total value and regard all these appliances together using 15 Amps. This is not the right approach, because the breaker will be rated higher than the total combined power consumption of all the appliances. What you should do is that look at every appliance label on the back of the devices or the datasheet. Look at the maximum power consumption, the operating voltage of the device, the power rating in watts or in volt amps. Try to accumulate all the information and put it in a big list.

The second step is to create a worst case scenario of power consumption in your system.  We recommend that you don’t combine all the appliances power together and think that is all the inverter need to power, you probably substantially oversize your inverter. For example , you might have laundry machine and a dryer, some people never ever use the two at the same time, that would drastically reduce the worst case scenario consumption power and reduce the requirements that capacity size of your inverter. Most of inverters in the market have automatic protection function build-in. If you turn on few appliances at the same time and exceed the maximum rated power, the inverter will shut off all the power and can retry again after 10-20 seconds.

The third step is actually measuring the consuming power of your appliances, because the Max. rating power that you find on the label is not always be the amount that you are using. Sometimes, the Max. rating of the appliances is several times higher than what on average the appliances is using for your setup. For example, if you have a fridge that has ice maker but you never use it, the average consumption of the unit will significantly less than the max rating power.  It is pretty easy to measure the actual power consumption of your appliances, we highly recommend that you buy an energy monitor which is a small device that you would plug into your wall outlet and also into this energy monitor, you would take the plug from your device from your fridge or whatever you plug it in there and let it run for a day or few days. It will monitor the maximum, minimum and average value. Few days later, you can know exact what the maximum power consumption is of these appliance.

After these steps, you can determine exactly what size inverter to choose for your system