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Power inverter; sine wave vs modified; a simple guide

If you’re either looking for a power inverter or you’re trying to find devices to power, you’ll need to know the difference between the two and how get the most out

The right kind of power inverter is going to make life on the road a tiny bit more like home.

Whether you’re setting up your semi truck, RV or other vehicle, Choose wisely, and you’ll be able to effortlessly convert DC power from your truck batteries into usable AC power – generating all kinds of small kitchen appliances, TVs, computers, cordless tools, and mostly everything else you can think of that would (normally) jack into wall outlets.

 Choose incorrectly, though, and the wrong power inverter is going to make your life on the road really rough. You’ll likely burn out your inverter or the device you connect to it, which of course will get expensive quick.

 Not only will your electrical appliances, tools, gizmos, and gadgets not run reliably with the wrong kind of inverter, but you also run the risk of power surges, flipped fuses, and even fires.

 But don’t worry. By the time you’re done with the inside info below that I have to share with you you’ll know exactly how to decide on the power inverter that will fit your needs. 

 All you have to do is understand the difference between pure sine wave inverters vs modified sine wave inverters and you are good to go.

Power Inverters – Sine vs Modified; What’s the Difference?

Pure sine wave inverters provide a cleaner, consistent electrical energy for appliances like electricity in your home. Modified sine wave inverters are cheaper but less reliable and may cause damage to some appliances.  

Video: Pure vs Modified Sine Wave Inverter

What is a Modified Sine Wave Inverter?

A modified sine wave inverter (here) is going to work well with (most) of the stuff you might want to run when you are holding down the road, though you are going to sacrifice at least a little bit of power and a little bit of efficiency for sure.

There are a couple of things you want to avoid running with a modified sine wave inverter because of these power inefficiencies, though, including (but not limited to):

  • Most refrigerators, fans, and even air conditioners
  • Extra lighting components (especially LED lighting components)
  • Any appliances that have timers or digital clocks you want to be reliable, or any appliances that need peak power as opposed to consistent power supplies

Other than that, though, you’re going to be able to rock ‘n’ roll with a modified sine wave inverter and not have too much trouble at all.

The power inefficiencies we mentioned above usually won’t be noticeable with your smaller appliances (things like a coffeemaker, for example), though they will start to show when you’re running something like a high-powered microwave.

Even then, though, you’ll generally only end up using about 20% more power compared to a pure sine inverter – which is definitely a lot of extra juice, but it’s not a dealbreaker (so long as you remember to run your vehicle before you flip the inverter on).

Turn the inverter on when your truck is turned off and you’ll no doubt end up draining your batteries down a whole lot faster than you ever would’ve thought possible. Dead batteries – not fun.

For truckers, you don’t want to rack up a bill calling a tow service or notifying your dispatch. You’ll never hear the end of it!

What is a Pure Sine Wave Inverter?

A pure sine wave inverter, on the other hand, is much closer to the kind of power supply that you’d expect to find in your home.

The power wave is a lot “cleaner”, is a lot more consistent, and is more capable of fluctuation – like when you power on a microwave and it demands a whole lot more power than it needs to actively run later down the line.

The biggest advantage in using a pure sine wave inverter, of course, is that the overwhelming majority of electronic devices and appliances are going to work right out-of-the-box when this is what you have hooked up to your rig electrical systems.

You don’t have to worry about power overloads. You don’t have to worry about drawing 20% more juice than you would have otherwise. You don’t have to worry about safety issues to the same degree with a pure sine wave inverter that you would have otherwise, either.

On top of that, a lot of appliances that use small motors (like refrigerators, for example) are only going to work well when they are running off of a pure sine wave system.

The same can be said for microwaves. You’re never going to be able to get full power output out of a microwave tucked into the cab of your vehicle if it’s hooked up to anything but a pure wave inverter.

The downside here, though, is that these kinds of inverters are significantly more expensive than the other options out there (modified sine wave and analog pure sine wave options).

There aren’t a lot of truckers unwilling to make the extra investment in something this reliable, something this consistent, and something this trustworthy, though.

sine vs modified wave power inverter

Do You Really Need a Pure Sine Wave Inverter?

Like we mentioned a moment ago, you don’t necessarily “need” a pure sine wave inverter to run extra appliances inside of your truck.

But it’s definitely sure better to have one than to have anything else.

A modified sine wave option is going to get the job done, but that square wave compared to a pure sine inverter is going to cause at least a little bit of headache and a little bit of hassle along the way.

Combine that with the extra amount of energy that these kinds of inverters force your appliances to soak up (upwards of 20%, like I talked about a second ago) and most truckers just don’t want to deal with those issues.

There’s nothing worse than going to fire up your microwave only to discover that it’s having a difficult time just flicking on, all because just enough peak power can’t be pushed to that appliance. That square wave produced by the modified sine inverter can be a nightmare.

Switch that to a pure sine wave option, though, and all of those issues disappear.

At the end of the day, though, either or will get the job done 99% of the time – one more conveniently than the other.

The only inverter that you really want to stay away from is the square wave set up.

Those kinds of inverters should really only be used to run simple tools with tiny, universal motor systems and very small electrical demands. You won’t be able to run any of your appliances off of a square wave inverter no matter how hard you try. Square wave power inverters are considered old and obsolete by today’s standards.

Avoid those at all costs and you won’t have much to worry about.

Affordability vs Safety

The major question that power inverter sine wave vs modified options boils down to is whether or not the affordability of a modified option is enough of a difference to make up for the safety and efficiency of the pure sine set up.

I can tell you with full confidence that there are plenty of truckers out there (many of them on the road right now) running their rig with a microwave – and probably a whole bunch of other stuff – jacked into a modified sine inverter set up.

Many of them might even be doing so with a smile on their face. Not all of them, but probably a bunch.

These are the kinds of drivers that are looking to pinch a couple of pennies, are unwilling to splash a little bit of extra cash on an inverter that’s only going to promise 20% more efficiency or so, and something that very rarely poses a safety risk no matter what.

On the other hand, there are plenty of drivers out there that will not drive at all without a pure sine wave inverter plugged onboard their vehicle. Many pro OTR drivers use them to power mini fridges, microwave ovens and other appliances. 

These are the kinds of drivers that are willing to pay a little bit more money to get better equipment, more consistent equipment, and improved safety features without having to worry at all about their inverter or the appliances they have plugged into it.

Where you sit on that spectrum is going to be entirely up to you.

All I can say is that most people that have had to fight modified inverters end up getting their hands on a pure sine set up later down the line, ending up spending a whole lot more money on two different inverters when they could have just skipped the hassle in the middle altogether.

Final Verdict

When you get right down to it, whether or not you go with a modified sine inverter or a pure sine inverter will really depend on what you’re trying to power.

power inverter sine wave vs modified

You’ll be able to run (almost) all of the same appliances, tools, gadgets, and gizmos on both kinds of inverters – you’ll just be able to run them more efficiently, more reliably, and more consistently on a pure sine than you will be able to on modified.

 Modified sine wave inverters tend to work best for smaller gadgets that don’t have bit power consumption and will work fine for most things. You can save a few bucks getting one if you don’t need the big pro setup.

Decide what you’ll need to power and if it’s worth the extra expense. For most people the modified inverter is fine (I’ve used one on and off for years) but if your looking for something more pro to provide power, you’ll want to step it up and get the pure sine wave inverter. 

Check out our guide of the best power inverter for semi trucks that contains both modified and pure sine wave inverters.

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