When it comes to buying inverters, one of the most common mistakes people make is choosing an inverter with the wrong size, one that cannot handle their power requirements. As a result, the appliances they want to use refuse to start or the inverter fails altogether. If you're planning to purchase this device, here's how you can calculate the capacity or size of the inverter that will suit your requirement so you can avoid making the same mistake. 
No 1: Determine the power requirements of the appliances you want to use. The amount of power an appliance need is expressed in watts and many appliances and power tools have their wattage rating indicated on the product itself. Wattage rating can also be calculated by using this formula: volts (120) x amps = watts.
Here are some of the common household appliances/power tools and the amount of electricity needed to operate them continuously:
| Appliance Cell Phone |
Watts 24 |
| CD Player | 40 |
| Satellite Dish | 75 |
| Printer | 75 |
| Laptop | 60-90 |
| Computer & Monitor | 400 |
| Blender | 400 |
| Refrigerator | 500 |
| 1/2″ Drill | 700 |
| Coffee Maker | 800 |
| Iron | 1000 |
| Sub Pump | 1000 |
| Space Heater | 1000 |
| 40″ Fan | 1100 |
| Toaster | 1200 |
| Circular Saw | 1250 |
| Microwave | 1250 |
No 2: Identify the starting power requirement of the appliance you want to use. Now that you know how much power is required to continuously operate an electric appliance, the next thing you need to do is determine the power required to start it. Take note that it usually requires more power to start a device than to continuously use it. Use the table below as reference:
| LED lights | 3-4 times its continuous power requirement |
| refrigerator | 3-7 times |
| microwave | 1 1/2-2 times |
| TV | 3-4 times |
| fan | 3 times |
| computer | 1 1/2-2 times |
| air-conditioner | 3-7 times |
| water pump | 3-7 times |
| drill | 2 times |
| coffee maker | 3-7 times |
| electric hairdryer | 1 1/2-2 times |
To determine the starting power of a particular appliance, use this formula: Watts X starting power. Using the formula and table above, this means that a TV that typically runs on 1000 watts of electricity will require 3000 watts of power to start it up.
1000 watts (continuous power requirement) x 3 (starting power requirement) = 3000 watts.
No 3: Check the inverter's peak power and continuous power rating. Pure sine wave inverters supply two power needs: continuous/typical and peak power/surge. Surge or peak power is basically the maximum power the inverter can provide, usually for only a short period of time. This is a key requirement when starting up appliances that have electric motors and those that require a much higher start-up surge power than they do when running. On the other hand, typical or continuous power is what 24 and 12v inverters need to supply on a steady or continuous basis.
When you take a look at inverters, you'll see two power ratings on the product (600w/1200w inverter, for example). The first set of digits indicate the inverter's continuous power rating while the second set of digits is the device's surge or peak power rating.
No 4: Use the appliance's starting power requirement as basis for choosing an inverter. To determine the size of the inverter you'll need, consider the amount of power you'll require to start an electric appliance. So based on the TV example above, you will need a 1500w/3000w inverter because it has a peak power of 3000 watts, which can support the TV's 3000-watt starting power requirement.
Whether you need a 12v or 24v inverters, Elinz Electronics has exactly what you need. Visit us today!
