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How to Choose the Right Inverter


A power inverter is a device the changes DC (direct) current into AC (alternating) current. A vast majority of electrical appliances run off of AC power - the entire US electrical grid is based on AC power. An inverter allows you to power standard electrical appliances directly from a battery or bank of batteries without having to use a standard wall outlet plug. The purpose of this post is to help you gather necessary information and steer you in the right direction of finding the correct inverter for your power needs.

What are you looking to power?

This is square one - you will need to decide on the exact item or items you’re looking to provide power for. I say items because many inverters out on the market today have more than one plug, some even have multiple USB ports for mobile phone and tablet charging. It's important to come to a decision as to what items you would like to use the inverter for and if you're going to be plugging the items into the inverter at the same time.

Find your total wattage and surge wattage draw

You have your item or list of items that you're looking to use with your inverter, now it’s time to find the total wattage draw of these items. This information is typically found on the manufacturer's label which should be right on the item itself, or on the transformer (if there is one). If you are not able to find that information I would recommend going to the manufacturer's website for that item and see if the information is posted either in the general description of the product or in a specifications PDF. The worst case scenario is that you will have to either call or email the manufacturer directly and wait a day or two to get a response. Getting the correct wattage information will save you time, a possible headache, and money down the road - no one wants to get an inverter and hook everything up only to find out the unit is unable to power their appliance.

What the heck is surge wattage? Surge wattage is the amount of wattage used to start the appliance. For example, let's say you have a coffee maker that requires a continuous 300 watts. When you first turn the coffee maker on, it will most likely draw at least double its rated wattage consumption (600 watts) for a few seconds before lowering its power needs to the stated 300 watts. A good rule of thumb for finding your surge wattage number is taking the stated wattage consumption of an item and doubling it.

Surge wattage is typically shown as ‘Peak Watts’ in most inverter descriptions and advertising and is double the regular wattage output of the inverter in most cases. When you're looking for the right inverter you will use your total regular wattage draw and the surge draw as a reference point when comparing different inverter models.



Do you need a pure or modified sine wave inverter?

There are two types of inverters - pure sine wave and modified sine wave. Which style of inverter you will need depends on the type of equipment that you are going to power.

Pure Sine Wave
Common items that would require a pure sine wave are medical devices, oxygen concentrators, sleep apnea machines, fax machines, high resolution TVs, and devices with variable speed motors. Some appliances with electric motors and microwave ovens will only produce full output with a pure sine wave.

Modified Sine Wave
Common items that would work using a modified sine wave are small appliances such as laptops, cell phones, electric blankets, PCs, coffee makers, most stereos, ink-jet printers, refrigerators, most TVs, and microwaves.

The modified sine wave inverter is by far the most popular series for us here at High-Tech Battery Solutions as well as the most cost effective. However, if the item you are looking to power falls into the category of pure sine then you must get a pure sine wave unit in order to properly operate your item.

Gather your information


Now that you have all of the required information I suggest you organize it into something legible that you can reference when you're inverter shopping. For example, Jim is going camping this weekend and is looking to power two things at the same time - a laptop and a small fan. He found the wattage consumption for the fan to be 250 watts, and his laptop would need 150 watts in order to function. Jim made up the following table to reference when he goes inverter shopping:



Appliance

Wattage Draw

Surge Wattage (Peak)

Laptop

150

300

Fan

300

600

Totals

450

900




Based on the information that he collected Jim now knows that he needs to look for at least a 450 watt inverter with a peak output of 900 watts. Keep in mind that it’s always a good idea to get an inverter that has a higher wattage rating than your bare minimum requirements, doing so will ensure that you have the power you need when you need it.