Best Inverter for an RV – Pure vs Modified and Watts
When we first purchased an RV we didn’t really understand power inverters, we only knew what mattered: An inverter converts the battery power (12 Volt DC) into power that works with our electronics (110 Volt AC power). After one year on the road the charger and battery on my laptop stopped working, and thus began the tireless research to find the best power inverter for our RV. Below is my take after two years of research, conversations with dozens of service techs, and getting it straight from the “horse’s mouth” (RV mfrs. and inverter mfrs) on why we ended up with a 3000 watt pure sine wave inverter.
Let’s start where it all begins: The Factory.
When you talk to RV Manufacturers the saying goes something like this: “if you want your RV built with all the highest quality products, fit, and finish…the rig would cost $5 million!” There might be a little exaggeration there but you get the point: in general RV manufacturers cut corners and install middle-of-the-road products to save you money on the MSRP. Our Monaco Vesta came equipped with a basic 1500 watt Modified Sine Wave Inverter and charger (that’s right the charger is built into the inverter, which is not good, but I’ll save that for another post). The factory installed inverter is pretty much the “go-to” for many RV mfrs, it works fine for many circumstances, but it’s not made to run all the expensive gadgets that typically end up in an RV.
Which is Better, a Pure Sine or Modified Sine Inverter?
While researching a new laptop battery and charger I noticed HP recommends a Pure Sine Inverter for their laptops. About that same time our Nespresso Milk Frother stopped working and I had some of my rechargeable AA batteries go bad. So I dove into researching Modified vs. Pure Sine Inverters. If you look at the facts, and don’t consider price, a pure sine inverter is a no brainer. Of course that one caveat is a huge one, and the main reason we delayed switching from a modified inverter right away (currently a Pure Sine inverter can cost between 2 and 5 times more than the same wattage modified version). If you’re planning to do your own research on modified vs. pure (which I highly recommend) you should know that Modified sine is sometimes referred to as “stepped sine” and Pure sine is sometimes referred to as “true sine”.
Does this Sine Wave graphic mean anything to you?
- Pure sine is a direct replica of the power in your house, and it’s what all 110 Volt electronic devices are made to run on (i.e. anything with a 2 or 3 prong plug).
- The more sensitive (read “fancy”) the device, the less likely it will work well on a Modified Sine. For example our induction plate wouldn’t even run on our old Modified sine, but runs perfectly on our new Pure Sine. Newer devices such as camera batteries, air purifiers, computers, tablets, LED TV’s, power tools, etc. may be damaged over time when used on a modified sine wave.
- Pure Sine power outlets are often protected by GFCI (you know the little test/reset switch that’s built into bathroom outlets that disconnects power to protect electronics).
- Pure sine is more efficient. The best example is with boiling 1 cup of water in a microwave: on a pure sine it takes 1 minute, on a modified sine it takes 2. Using less energy means you can use more devices, or save money by installing less solar or batteries.
- The biggest part for us is not having to replace sensitive gadgets on a semi-regular basis: Laptop Battery $140; Laptop Charger $80; Milk Frother $100; AA Rechargeable Batts $15
Just to be clear, a Modified Sine Inverter will run many devices, especially basic ones like a griddle, electric kettle, hair dryer, etc. If you’re not planning on powering any techy gadgets (you know fancy, sensitive, expensive, etc) save your money and go for the Modified Sine, it’ll most likely serve your needs just fine (but don’t say we didn’t warn you!).
A Kindergarten Drawing of Other Sine Waves
How many watts do I need for an RV inverter?
Our old inverter was 1500 watts, and for the most part it provided enough power, but there was one thing that really eeerked me: it had a 15 amp built in fuse that would trip every time we would run the microwave and any other device at the same time. For example: On “Movie Night” we’d power the DVD player/Home Stereo and the LCD TV. If we felt the urge for the full theater experience we’d start to pop some popcorn…and…Goodbye Power! No matter if we were plugged into shore power, running the generator, or using solar we had to keep track of what devices were plugged into the inverter outlets; it was a constant headache because the majority of the outlets in the kitchen were wired through the inverter, thus making me run outside no matter the weather or hour of the night to flip a stinkin fuse switch! Yes, it was a pain in my butt!
For our inverter upgrade we wanted to power additional outlets in the RV (1 in the bathroom, 2 in the living area, and 1 by the driver’s area), but most importantly we wanted to watch a movie and have our popcorn too! So we chose a 3000 watt pure sine inverter. With 3000 watts Nikki can blow dry her hair while I’m making breakfast using the electric kettle and griddle. In my humble opinion 1500 watts isn’t enough for a full-timer, like they say “go big or go home”!
Buying an Inverter
If you’re looking to purchase an inverter we’ve found the best prices are on Amazon(at least from reputable sources). Here’s a link to the 3000 Watt Pure Sine Inverter that we installed: Go Power! GP-SW3000-12 3000-Watt Pure Sine Wave Inverter
Hope this breakdown helps you find the perfect inverter for your RV. If you have any questions or personal experience with Inverter Wattage, Modified vs. Pure Sine, don’t hesitate to leave a comment below, we’d love to get a discussion going on this often misunderstood RV topic.
2015 Update: We have an all new improved solar set up. Click the button to see our most recent upgrades:
Disclaimer: Take our recommendations for what they are: our opinions! We are not “experts”, we’re just “users”. Go Power! provided our inverter for testing however our opinions are not purchased and are 100% our own.