Overall, pure sine wave inverters are preferred over modified sine wave inverters when it comes to powering sensitive devices like microwave ovens, game consoles, laser printers, compressors, and more on the go.
That’s because the output voltage you get from these handy equipment is a perfect replica of power utility-supplied energy (has incredibly low harmonic distortion).
But like it happens with man-made machines, a pure sine wave inverter could disadvantage you in a couple of ways.
This article looks at the main disadvantages of pure sine wave inverter also called true sine wave inverters to help you make a wise choice.
We will look at the basics first.
How does a pure sine wave inverter work?
To generate a current that’s as stable as the grid power, a pure sine wave (PSW) inverter takes the voltage from the battery through three stages:
- Oscillation: The inverter starts by making oscillating pulses using a transistorized circuit (an IC circuit). An inbuilt oscillator coordinates all the steps in the oscillation process.
- Amplification: To work smoothly, the AC current output by the inverter must be as powerful as the mains electricity. To this end, the pulses produced by the oscillator are boosted to attain an elevated current level.
The critical stage is this time controlled by the included amplifier.
- Output Transformation: The voltage received from the amplification step is still at the DC battery supply level and cannot effectively power your various electronics. It is now passed through a transformer to be converted to an AC current that can operate your planned electrical appliances.
Of course, the installed output transformer oversees the DC-AC alteration procedure.
As you may be aware, the signal your PSW inverter releases can be used to power all electronic devices during your camping/ boating trips.
This broader range of applications also makes PSW inverters more advantageous as a source of emergency electricity at home and businesses than MSW inverters.
Let’s now turn our attention to the issues surrounding PSW inverters.
Disadvantages of pure sine wave inverters
The most common cons of pure sine wave inverters are:
· The higher cost of pure sine wave (PSW) inverters
Let’s start with the issue that most complain about: cost.
Now, pure sine inverters are costlier than modified sine wave inverters per watt because the technology they use to generate their cleaner energy is more sophisticated.
Unsurprisingly, you will always pay substantially more for a PSW inverter than an MSW inverter with the same watts.
For this reason, it’s always good to assess if you really need a pure sine inverter before making an order.
You see, the less expensive modified sine inverters work perfectly for appliances that don’t use rectifiers and those that can be efficiently powered by a regular DC adapter and there would be no point in spending tons of money on a pricey PSW inverter if you plan to be powering such equipment.
In other words, the only time you need to purchase a pure sine inverter is when you need portable/backup power for devices that primarily run more efficiently with a PSW inverter.
Here is a list of some of the tools and appliances that work well with PSW inverters to guide you:
- All electronics that comprise AC motors (or inductive loads), for example, refrigerators.
- All power tools employing solid-state circuitry or variable speed control.
- Medical apparatus especially those that use a heated humidifier, for instance, a CPAP machine and oxygen concentrators.
- Some computers (including selected laptop models) and related equipment such as laser photocopiers, printers, and some hard drives.
- Certain fluorescent lamps (mostly using electronic ballast for current regulation).
- Heating systems with microprocessor control including some new furnaces.
- Sewing machines featuring speed/microprocessor control.
- Intelligent microwaves and ovens.
- Digital clocks (models with radios).
- Intelligent battery chargers for your cordless tools.
- Capacitive input-powered devices without transformers such as flashlights, smoke detectors, etc.
- Most light dimmers
- Other electrical devices with microelectronics installed such as toasters, shavers, hair straighteners, electric toothbrushes, etc.
If you won’t be powering these machines, then you’re probably going to be okay with a PSW inverter with proper wattage.
However, as a precaution, read the paperwork that came with the device (or speak to the manufacturer) to ascertain if a pure sine wave power is necessary.
· Shorter battery running time
PSW inverters generally use DC power more inefficiently than MSW inverters and your battery may not last as long as when you’re using a modified sine wave inverter.
One of the reasons behind this behavior is the complex technologies integrated into the circuitry of pure sine wave inverters because it will consume some of the battery voltage.
The other reason is the deployment of heavy, inefficient transformers in PSW inverters.
An MSW inverter might, therefore, be a better option if you plan to be powering normal lighting bulbs and other non-intensive power consumers as long as they’re compatible with modified sine wave inverters.
Disadvantages of pure sine wave inverter: frequently asked questions (FAQs)
Q: Do computers need pure sine wave?
Well, while some PCs survive the inefficiencies of MSW inverters, a pure sine wave eliminates the guessing if you’re thinking of just running it off an inverter.
Computers actually run better on pure sine wave, even those designed to work with MSW inverters so it could be the best option if you have the finances.
Having said that, the best way is obviously to check the power specifications of your computer to be sure if it could run from a modified/true sign wave before making a purchase.
Q: What is the best pure sine wave inverter?
The short answer is that it depends on your needs.
Overall, when choosing an inverter, you should consider issues like the wattage you need (according to what you’ll be plugging in), the array of features you could require (think of USB ports for charging, overload protection, a good display to track current DC voltage, and more).
Your budget will also have a major say.
Wrapping it up
You don’t need to worry to have about the above-mentioned disadvantages of pure sine wave inverter as plenty of devices work safely with modified sine wave inverters (with the exception of delicate equipment indicated in the list).
You still need to be aware of potential drawbacks with MSW inverters such as interference before making a choice.
In short, it’s important to focus on the opposite sides of both sine waves when shopping for an ideal inverter for your RV, boat, home, or camping needs.