# How Important Is Sine Wave?



## BoaterDan (Jul 1, 2005)

I asked this in another thread, but thought it merits its own.

Everybody, including me, assumes they need to buy one of the drastically more expensive models that outputs a clean sine wave.

But why? I understand the "dirty" power will cause things like noise on radios, unstable pictures on televisions and all manner of quirkiness on computers, but what if you just want to keep the batteries charged, and possibly run the microwave or air conditioner?

If someone is going to respond that the dirty waves can damage the electronics in the microwaves and air conditioners (I've heard that), what about if you hooked up the generator but didn't use those devices?

I've searched through some other threads and even other forums (ahem), and some people sounding very knowledgeable have used the el-cheapo models, including to run A/C in some cases.


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## PDX_Doug (Nov 16, 2004)

Dan,

I think it all comes down to the use of solid state electronics. If you do not use a sine wave generator, you are in big danger of frying the electronics (which will cost you a lot more to replace than the up charge for the sine wave generator in the first place). If you are only using the generator for things like charging your batteries, running lights and motorized equipment (drills, saws, etc.) you will be fine. The danger comes with all the appliances in the TT that are controlled by electronic circuit boards. To me, the savings would not be worth the risk.

Happy Trails,
Doug


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## Scoutr2 (Aug 21, 2006)

PDX_Doug said:


> Dan,
> 
> I think it all comes down to the use of solid state electronics. If you do not use a sine wave generator, you are in big danger of frying the electronics (which will cost you a lot more to replace than the up charge for the sine wave generator in the first place). If you are only using the generator for things like charging your batteries, running lights and motorized equipment (drills, saws, etc.) you will be fine. The danger comes with all the appliances in the TT that are controlled by electronic circuit boards. To me, the savings would not be worth the risk.
> 
> ...


X2. Every appliance in your Outback uses an electronic circuit board for controlling the appliance. To me, the risk outweighs the difference in price between the two types of generators. The type of generator you are talking about is most commonly used on construction sites to power circular saws, etc.

Spend the few extra bucks and sleep well at night, knowing that the generator won't damage anything.

Just my $.02.

Mike


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## bradnbecca (Feb 12, 2007)

I am on my fourth RV now. Have used a non-invertor genny in every one and have had no problems whatsoever. Heck when I got my first TT, there was no such thing as an invertor generator. I have never had a problem with damage from usnig a non-invertor generator, and don't have any personal knowledge of anyone who has. I have, however, had a big time problem caused by spikes in the CG power supply though.

You hear lots of people tell you that a non-invertor generator will be the ruination of your rv, but again, there doesn't seem to be much evidence that proves that out from real life experience.

YMMV.

eta- food for thought. The RV generators made by Onan and Generac are not invertor type generators, but they have been used for years, even being supplied as options by the RV manufacturers. Onan has started offering invertor generators, but not as built-ins for RV's. Just something to ponder . . . . .


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## BoaterDan (Jul 1, 2005)

bradnbecca said:


> You hear lots of people tell you that a non-invertor generator will be the ruination of your rv, but again, there doesn't seem to be much evidence that proves that out from real life experience.
> 
> YMMV.


What I found in a few minutes of google research was that it was mostly ham operators or people concerned with their television picture that were talking about needing them. No mention of frying electronic controls of a refrigerator, just people concerned with the "noise" introduced by the malformed waves or inconsistent AC frequency.

Having said that, does anybody have any knowledge of cases where electronics fried as a direct result of using a non-inverter generator?

BTW, we're not talking about a "few bucks". The difference is easily $500, probably more. That pays for a lot of camping.


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## sleecjr (Mar 24, 2006)

There are other things to consider in the price. Cost of gas. Most non inverter types must run and full rpm to maintain voltage. Doing that most use a little less then a gallon of gas per hour. Inverter types don't need to run a full rpm, unless you are pulling full power from them. This saves you a lot on gas! My Honda 2000 will run 15 hours on 1.1 gallon's of gas at 25% load. It depends on how much you will use the gen, but gas can add up quick. Here are some basic numbers. You need to look at how much gas the one you are looking at uses and compare it to the inverter type you are looking at for the exact numbers. You will find under normal loads 25% of the gas is not a stretch.

250 hours of use.

.8 gallon per hour= 200 gallons. 200 x 2.75gl= 550.00
.2 gallon per hour= 50 gallons. 50 x 2.75gl= 137.50


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## raynardo (Jun 8, 2007)

The end result is you always get what you pay for.

I love my Honda eu2000i, it's quiet (my camping neighbors probably love that more than I do!), it's fuel economy is outstanding, and it delivers the clean power that all of today's modern electronics really require (I travel with 2-laptops, flat screen TV/DVD, and a gaggle of different battery chargers). I'm probably going to purchase a second one, along with the parallel kit so that I may hook them together and have enough power to run the A/C.


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## biga (Apr 17, 2006)

I have no real evidence one way or the other, but for me, I would love to have a Honda 3000, but I can't justify $2000 for a generator I will use 1 or 2 times per year. So, I have a refurbed Coleman 6250W that got with a warranty for $400. I can justify that. It is also big enough that I can run my house off of it (except maybe the AC) in the case of an emergency.

Now, I see the argument about the unclean power coming from one of these generators, but I have seen some REALLY bad power in a few campgrounds in the year and a half that we have had our Roo. So , I have considered adding a RV surge protector to the camper which would help with the parks, and the generator.


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## SoCalOutback (Dec 18, 2005)

Here is a link to the xantrex FAQ that discusses the use of a modified sine wave inverter verses a true sign wave inverter. The info holds true for generators as well as stand alone inverters.

In general most electronics will work fine with a modified sine wave. The AC units on the outbacks are certified to run with the Onan generators that are modified sine wave. The refrigerators are also able to run with modified sine wave.

I have a honda EU2000is for size and its low noise output. When I want a lager genset I will probably by an onan modified sine wave and save a few $$$$.


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## N7OQ (Jun 10, 2006)

As far as I know all generators put out a true sine wave, it is Inverters that come as true sine wave or modified sine wave which is more like a square wave output. Generators come as Inverter type like the Honda, Yamaha, or Kipor, these use a alternator that feeds a true sine wave inverter can produce 120 volts at 60 hz at a idle. The other type of generator is a motor generator, a motor runs a generator and has to run a constant RPM to produce 60 hz. like 3600 rpm. Simple motor generators use more fuel, and usually are louder also if you add a heavy load your frequency will drop until the motor can catch up and get back to 3600 rpm's during this time the duty cycle is longer putting a load on your equipment and expensive solid state equipment might not handle it. If you are going to use a non inverter type generator buy one that is rated higher in watts than you will need that way a when a load kicks in like a the AC unit it won't struggle to get it going and it will stabilize quicker.


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## Carey (Mar 6, 2012)

I had read last spring, that this fall Champion Generator company will offer there rv gen with an idle down feature. The price will still be in the 300 dollar range. i have used mine a year now and no trouble. It does put out a pretty clean wave for a cheapy china gen.

One thing about the champion rv gen, is it will not start the ac above 5000 feet elev.. Just doesnt make enough power.. Needs a carb mod.

The main reason I bought a china gen is my gen is permantly mounted on the rear of our roo. Tt would be pretty stupid to mount a honda/yami gen permantly.. We leave our camper all the time when we go camping. We dry camp only. So the entire camper is vunerable to theft, as it sits all by itself in the mountains for the entire day while we are out riding dirtbikes.

if someone steals my champion gen, no biggie, as it was only 300 bucks anyway.

Carey


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## BoaterDan (Jul 1, 2005)

Well, I guess the question now is whether generators make sine waves. I understood that the problem with the cheap non-inverter sets is that the waves are actually squared off.

The evidence seems to be clear, including the FAQ of a manufacturer, that modified sine wave is fine and true sine wave is likely an unneccessary expense. But I think the question (as I meant it anyway) is really between the $300 el-cheapo non-inverter model and the $1000-$3000 inverter sine wave deal.

Here's something to think about. I've never heard anybody think twice about using one of the cheapo models at home for emergencies. Even the large sets sold at Home Depot for wiring directly into the home's electrical supply aren't inverter based. But aren't there at least as many sensitive electronics in your home than in your trailer?


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## kjdj (Sep 14, 2004)

I think we are confusing two issues and uses.

In an RV situation Loudness is key. The "inverter" generators are quiet.
With my TV / Sound System business, frequency/voltage regulation, and lack of noise, hum, distortion, and buzzes are key.
For my use expensive is good.

If you need a generator for the house or RV a non-inverter is fine were noise and tight frequency/voltage regulation and distortion is not a huge issue.

The Honda, Yamaha, and Kawasaki "inverter" generators are true sine wave. I have no experience with the China made units. The may well be modified sine wave. But for RV use they are great because they are quiet and inexpensive.

I think the cheap inverter you refer to is the 12volt battery to 120 volt AC modified inverters.
They do make expensive 12volt battery to 120 volt AC true sine wave units are used in ambulances and such were sensitive test equipment is used.

As far as hardwired home units, the regulation is electronic rather that mechanical like a portable. In fact Home units have been found to deliver more stable cleaner power than the power company.


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## bradnbecca (Feb 12, 2007)

OK, in the same vein. I have been contemplating a generator for our new SOB coach. I am debating between a Generac 5500w built in, which will require a good bit of modification to the trailer, or going with a Kipor 6000 invertor and just getting a second shore power outlet installed on the pin box like we had on the OB that we just sold.

For all you who are much more electrically literate than I am, this is my question: The Kipor has a 30 amp rv outlet, but also has this outlet: _One 240-V 50-A 14-50R_. Is this the same as the 50 amp receptacle that you would find on a power pedestal in a park? The 240v is what is throwing me. The outlet appears the same as the plug on the trailer, but is it?

Come on guys, I am trying to join the invertor crowd here (although the contemplated change is being driven as much economically as by a desire to be socially responsible . . . .)

Any electricians care to enlighten me?


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## N7OQ (Jun 10, 2006)

bradnbecca said:


> OK, in the same vein. I have been contemplating a generator for our new SOB coach. I am debating between a Generac 5500w built in, which will require a good bit of modification to the trailer, or going with a Kipor 6000 invertor and just getting a second shore power outlet installed on the pin box like we had on the OB that we just sold.
> 
> For all you who are much more electrically literate than I am, this is my question: The Kipor has a 30 amp rv outlet, but also has this outlet: _One 240-V 50-A 14-50R_. Is this the same as the 50 amp receptacle that you would find on a power pedestal in a park? The 240v is what is throwing me. The outlet appears the same as the plug on the trailer, but is it?
> 
> ...


Yes the 240v 50a 14-50r is the outlet a RV with 50 amp service would use, it really should be listed as 120/240v 50a 14-50r. The outlet puts out 120 volts from X to W and from Y to W and 240volts from W to Y But if you were to use this plug for 50 amp service you would not get the 50 amps out on both sides sense the generator can only put out about 46 amps you would have to split that between both sides. Look like a really nice generator. I have the much smaller Kipor 3000 thi but it will run my AC even above 6000 feet and only weighs 65 lbs.


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## bradnbecca (Feb 12, 2007)

N7OQ said:


> OK, in the same vein. I have been contemplating a generator for our new SOB coach. I am debating between a Generac 5500w built in, which will require a good bit of modification to the trailer, or going with a Kipor 6000 invertor and just getting a second shore power outlet installed on the pin box like we had on the OB that we just sold.
> 
> For all you who are much more electrically literate than I am, this is my question: The Kipor has a 30 amp rv outlet, but also has this outlet: _One 240-V 50-A 14-50R_. Is this the same as the 50 amp receptacle that you would find on a power pedestal in a park? The 240v is what is throwing me. The outlet appears the same as the plug on the trailer, but is it?
> 
> ...


Yes the 240v 50a 14-50r is the outlet a RV with 50 amp service would use, it really should be listed as 120/240v 50a 14-50r. The outlet puts out 120 volts from X to W and from Y to W and 240volts from W to Y But if you were to use this plug for 50 amp service you would not get the 50 amps out on both sides sense the generator can only put out about 46 amps you would have to split that between both sides. Look like a really nice generator. I have the much smaller Kipor 3000 thi but it will run my AC even above 6000 feet and only weighs 65 lbs.
[/quote]

Thanks for the quick reply. I think this generator could be a winner, as it puts out over 5kw at less than the price of two 2k Hondas or Kipors with a parallel kit. The only downside is the weight, but I am not planning on moving it once I get it in place anyway. I can get one locally for about $1600.

Back to the 50 amp service- If I understand it correctly, the power management systems of most rv's actually only use 30 amps on each leg of the 50 amp service- is that also correct? I would imagine the power would be limited by the size of the breakers on each side of the system . . . .


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## kjdj (Sep 14, 2004)

bradnbecca said:


> OK, in the same vein. I have been contemplating a generator for our new SOB coach. I am debating between a Generac 5500w built in, which will require a good bit of modification to the trailer, or going with a Kipor 6000 invertor and just getting a second shore power outlet installed on the pin box like we had on the OB that we just sold.
> 
> For all you who are much more electrically literate than I am, this is my question: The Kipor has a 30 amp rv outlet, but also has this outlet: _One 240-V 50-A 14-50R_. Is this the same as the 50 amp receptacle that you would find on a power pedestal in a park? The 240v is what is throwing me. The outlet appears the same as the plug on the trailer, but is it?
> 
> ...


Yes the 240v 50a 14-50r is the outlet a RV with 50 amp service would use, it really should be listed as 120/240v 50a 14-50r. The outlet puts out 120 volts from X to W and from Y to W and 240volts from W to Y But if you were to use this plug for 50 amp service you would not get the 50 amps out on both sides sense the generator can only put out about 46 amps you would have to split that between both sides. Look like a really nice generator. I have the much smaller Kipor 3000 thi but it will run my AC even above 6000 feet and only weighs 65 lbs.
[/quote]

Thanks for the quick reply. I think this generator could be a winner, as it puts out over 5kw at less than the price of two 2k Hondas or Kipors with a parallel kit. The only downside is the weight, but I am not planning on moving it once I get it in place anyway. I can get one locally for about $1600.

Back to the 50 amp service- If I understand it correctly, the power management systems of most rv's actually only use 30 amps on each leg of the 50 amp service- is that also correct? I would imagine the power would be limited by the size of the breakers on each side of the system . . . .
[/quote]

Great mod!


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## Cheyenne (Oct 15, 2007)

Cheyenne's DH here....

My 2 cents for the original poster.... Your goal with any style generator or inverter is to obtain 120 volt AC power at a precise 60Hz frequency, and as close to a sinewave as you wish to afford.

*Inexpensive generators* (those without inverters) need to run at 1800 rpm (diesel) or 3600 rpm (gas) constantly to produce 60hz 120/240v power. They will produce a fairly low distortion sine wave by design, one as good as your home's AC power and possibly better. This is beacuse they are miniature versions of what the power company uses. Because they must run at a constant rpm no matter what the load is, they will burn more fuel than an inverter model and are likely to be louder. With this type of generator if a big load near the generator's capacity kicks on the power will hiccup a little (you'll see lights dim, TV's might get wierd).

*Inverter generators* internally produce "wild power" that varies in voltage and frequency depending on the speed the engine is running at. Electronics in the 'inverter' portion convert this 'wild power' into a stable pure 60hz 120v sinewave power. Because of the very interesting (and costly) design of these generators, the engine is controlled to run only as fast as needed to produce the watts you need at the time, and the electronics insure the resulting AC output is spot on 120v 60hz. The quality of this power is likely far better than your home's AC outlet. This type of generator is likely to be more well behaved near it's maximum, but is likely to shut down if you overload it.

*Modified Sine Wave Inverters* convert low voltage DC (like 12v) into 120v 60hz power. The power itself is very stable in frequency and voltage, but not at all a 'clean' sinewave. This type of power may not be great for some electronics. To be honest, though, most of the circuitry in newer electronics deal with this power just fine (laptops, computers, light AC wall adapters). Stuff with induction motors (fans, pumps, Airconditioners) or transformer based power supplies (heavy AC wall adapters, stereo equipment, microwave ovens, some TVs, etc) do pretty poorly on this type of power.

*True Sine wave inverters* are used extensively in solar power installations, and available for RVs at a price premium. These convert low voltage DC (like 12v) into 120v 60hz pure sinewave power. The quality of this power is likely far better than your home's AC outlet.

Hope this helps.


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## Sayonara (Jul 23, 2007)

WOW ! Thats a great breakdown of the different systems.


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## BoaterDan (Jul 1, 2005)

Yeah, thanks. That's exactly the information I was looking for.

The application I was considering was really just a 1k for battery charging and such. It's very light and inexpensive, and not terribly loud because it's small.


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