# Home usage of 12Vdc to 120Vac inverters



## ET1 SS (Oct 22, 2005)

My eldest son has walked away from a career driving OTR trucks, and has moved back home with us. We have been looking at what options we have for home generation of electrical power. I was pretty much set on a battery bank with solid state inverters, one inverter for each of our 120Vac circuits.

He says that while living on OTR trucks, most truck drivers use solid state inverters on-board for their TVs and PCs, when they are parked. And that they burn-out every few weeks. That it is common for truck drivers to be replacing their 120Vac inverters every 3 to 4 weeks.

Now is this so?

Currently our home is entirely 120Vac, and is powered by the utility company. If we begin with small projects to generate power, each project charging a battery bank. One circuit at a time, shifting over from using public utility electricity to our own electricity. Each of our home circuits are 15 amp, mostly. Will inverters burn out that quickly?

Or was his experiences and observation due to the moving trucks, their high vibration, and power spikes?

Thanks


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## Gary in ohio (May 11, 2002)

If your talking about the inverters your getting at truck stops then yes they are usually underrated and people put a larger load on them they should and they would not last very long. 


If your using a battery bank and plan to use inverters DONT skimp on the inverter. CHeap inverters will drain a battery in no time even if there is no 120v device plugged in. Make sure you also size the inverter properly. Voltage is only part of what you need. You also need current. Your typical 120v outlet at home is 15 amps, 15 amps is 1800watt and 20amps is 2400 watts. keep mind those are running watts, not peak watts. A good 1800 watt inverter will run you $1000.


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## Nevada (Sep 9, 2004)

While Gary's numbers are accurate, if you're living off an inverter you should only do things with electricity that can't be done with some other energy source. You should heat, cook, and make hot water with propane. Save your electricity for TV, computer, and lights. 

The refrigerator is a toss-up, since propane fridges are pricey. You are basically trading the cost of a propane refrigerator for the cost of solar panels. If you get an electric fridge you'll want a smaller (~10 cf) efficient (under 150 watt) model.

But as for your specific question about inverters, get a Black & Decker model. The problem with most inverters is that the cooling fan runs all the time, at least whenever any load at all is on the inverter. That makes the cooling fans run continuously so they wear out prematurely, causing general inverter failure. The B&D inverters are the only modified sine wave models I'm aware of that have cooling fans that turn on & off on the basis of temperature, so they last virtually forever. You can find B&D inverters at Walmart in the 200-750 watt range, selling for about $35 to $75 last I looked.

You DON'T want a pure sine wave inverter. They are not only prohibitively expensive (they are made for specialized consumers like phone companies, who operate sensitive equipment), but they are also horribly inefficient and run down your batteries fast. Stick with modified sine wave inverters.

If you follow my guidelines in the first paragraph you should be able to run your entire home less than 750 watts, but many off-griders shoot to stay less than 400 watts. If you're looking to live exactly as you do today on grid (washing machine, dishwasher, 24 cu ft electric fridge, A/C, forced draft furnace, etc.) you can look forward to a $30,000 project. That's not really a homestead project, that's more of a yuppie project.


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## Jim-mi (May 15, 2002)

What an apples to oranges comparison of inexpensive "truck stop" inverters to the likes of an Outback inverter retailing for $1800 bucks. Or a Magnum at $2400 bucks.

Yes those things are so cheap that most any little infraction will break loose that 'can of smoke' and then you have a paper weight.

Yes one of those cheapys could run for awhile >IF< you keep the 'load' well below its watt rate . 

Hopefully when some one has opted to spend $2k for an inverter they will have done enough homework to know its limitations also.


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## Jim-mi (May 15, 2002)

I beg to differ with Nevada.
Sine wave is the way to go.
>ALL< 'AC electrical appliances' are designed to run on sine wave . . . . . .period.
They run cooler, quieter, and much more efficiently.

Yes some will say "Well I run thus and such on mod sign"
Ask them how warm it gets and how much it hums . . . . .???
Or about the funny stuff in the TV pix.

Good affordable, efficient, battery friendly sine wave inverters are now available for 'any one'.

Unless of course you have only set up a budget of $129.95 to make up a "power system" for your place...........


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## greg273 (Aug 5, 2003)

Jim-mi said:


> I beg to differ with Nevada.
> Sine wave is the way to go.
> >ALL< 'AC electrical appliances' are designed to run on sine wave . . . . . .period.
> They run cooler, quieter, and much more efficiently.
> ...


 Right, if you are on an EXTREMELY limited budget, the el-cheapo 'truck stop' inverters will get the job done, but in the long run, if you want good clean Alternating Current, get a pure sine.
Now, I've run my small house/cabin for 4 years on one of the aforementioned cheap inverters, even clipped the fan wires to make in quieter (which effectively cuts down the rated output due to heating), but it has done its job well. Actually I have an old extension cord running from it to my 120volt AC distribution panel. Yeah, its kinda ******* looking, but it does the job. I'l get the better inverter wired up here shortly, just waitin to climb up on the roof and rewire the array for 24volts...oh, and buy about 4 grand worth panels...THIS year, before the tax credit expires.

Oh, and I have definitely noticed that some appliances run fine on mod-sine, some do not... for example, my TV has a non-polarized plug, and it HAS to be plugged in a certain way, otherwise it works, but the picture cuts in and out. And some cheap box fans hum so loud they are unuseable. For the fans, there seems to be no rhyme or reason as to why SOME brands dislike the mod-sine, and some work fine. I would think you would eliminate all such non-sense with a good quality pure sine inverter.


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## ET1 SS (Oct 22, 2005)

So the primary cost of off-grid home power production may well be the inverters.


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## Jim-mi (May 15, 2002)

No not really. Depends on how carried away you would care to go with "many" PV panels, or how large a wind turbine you can afford.

My point about the inverters is that you are much better off installing the good stuff to begin with. Those that have will a test to that.

It is unfortunate that some folks can not see or reason beyond a *K mart* price tag.


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## Windy in Kansas (Jun 16, 2002)

ET1 SS said:


> So the primary cost of off-grid home power production may well be the inverters.


A high quality, long life, deep cycle bank of batteries would probably tip the scales for most cost. If money were no object I'd opt for some of those submarine batteries.


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## Nevada (Sep 9, 2004)

Jim-mi said:


> I beg to differ with Nevada.
> Sine wave is the way to go.
> >ALL< 'AC electrical appliances' are designed to run on sine wave . . . . . .period.
> They run cooler, quieter, and much more efficiently.


I know that a lot of people differ with that opinion. However, it's my belief that changing your lifestyle is just part of going off-grid. If you want everything to stay the same then you're going to run into a lot of expense that can never be recovered, which defeats the whole purpose of going off-grid.

Planning for the off-grid change is as important a step as selecting your power generation equipment. You should consider the following.


Change as many appliances to gas operation as possible. Certainly use gas for heat, cooking, and hot water.
Consider going to more efficient appliances. Get rid of your CRT TV & computer monitor, change to helical compact fluorescent light bulbs, consider going to a laptop computer instead of a desktop, etc.
Consider replacing appliances that don't work well with modified side wave inverters.
Consider giving up certain luxuries, such as your microwave oven, electric coffee maker (I use a range-top percolator now), toaster (use the gas broiler), air conditioning (consider evaporative cooling), and others.
Get used to turning things off.
Don't expect to go completely off-grid without sacrifices. You can save an awful lot just by planning ahead and making certain adjustments in your life. Perhaps those are adjustments you should be considering anyway.


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## Explorer (Dec 2, 2003)

I have a small solar system much in the design mode Nevada listed. I use modified sine wave, sized at about twice my normal load. So far, after six months, no problems. However, I am not a purest and still learning about solar, so I am more interested in function.


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## PhilJohnson (Dec 24, 2006)

ET1 SS said:


> He says that while living on OTR trucks, most truck drivers use solid state inverters on-board for their TVs and PCs, when they are parked. And that they burn-out every few weeks. That it is common for truck drivers to be replacing their 120Vac inverters every 3 to 4 weeks.



My friend is a truck driver and he used the same inverter in his truck for the past year and a half. I bought myself a Cobra 800 watt inverter 2 years ago for 50 bucks and never had a problem with it. I also bought my self a Vector 2500 watt power inverter for 135 bucks and haven't had a problem with that one either. The 800 watt inverter is pretty much in continuous use all year round except when I need either more power or want to run audio equipment, I have a small 200 watt pure sine wave inverter for that. All three inverters have load sensitive fans, so the fans aren't running all the time. When going off-grid two years ago I never expected to have the same level of convenience as some one who has grid power. In my opinion it was worth it, I never have to worry about storms knocking out my power and I can go on the internet in the middle of a thunderstorm and not have to worry about a fried computer.


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## zant (Dec 1, 2005)

ETS-I lived offgrid for 7yrs in Me..I used a Trace sinewave inverter-the ONLY way to go.Everything runs cooler and more efficently on sinewave...All the inverter did was sit on the wall and perform wonderfully.never a problem...We had a propane fridge which I can't recommend-too small,ices up,needs maint,etc....In my truck I use a 1500watt inverter that just runs a small AC fridge and my computer-no problems-most drivers try to run too much on too small an inverter.I have a number somewhere of a guy outside Bangor that takes batteries out of power stations and scraps them-I bought 18,2volt C&D batteries from him that were 15yrs old and were in constant floatation-for 107.00-the govt paid 24,000 for them(our tax$ at work).I wired them for 12volts and used them for 4yrs with no problems-the debris sumps in the bottom were clear as a bell.If I can find number I will pm you.


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## no1cowboy (May 2, 2004)

The only problem I have useing my 3000w mod inverter is with the microwave, I will be getting a pure sin as soon as the buget alows


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## artificer (Feb 26, 2007)

Nevada said:


> You DON'T want a pure sine wave inverter. They are not only prohibitively expensive (they are made for specialized consumers like phone companies, who operate sensitive equipment), but they are also horribly inefficient and run down your batteries fast. Stick with modified sine wave inverters.


You've said this before, and I've always wondered why. How "horribly inefficient" are they? 89% doesn't seem that horrible. The compressor on the freezer runs quieter and with less power than if its on a modified sine wave.

Yes, they do cost more. You also tend to get a better inverter for your money. Most sine wave inverters have the fan control. They also tend to not die by using them at their rated wattage.

We have a B&D inverter, and it eats cheap fluorescent lights. Had to go with 12V LEDs for the chicken coop.

Michael




Michael


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## Nevada (Sep 9, 2004)

artificer said:


> You've said this before, and I've always wondered why. How "horribly inefficient" are they? 89% doesn't seem that horrible. The compressor on the freezer runs quieter and with less power than if its on a modified sine wave.
> 
> Yes, they do cost more. You also tend to get a better inverter for your money. Most sine wave inverters have the fan control. They also tend to not die by using them at their rated wattage.
> 
> ...


I know someone who acquired a pure sine wave inverter and his batteries ran down too fast. The problem when away with the modified sine wave. But even if all factors are equal, the price difference certainly creates a budget to replace applicances with those which get along better with modified sine wave.

To be honest, I haven't lost a compact fluorescent bulb yet, so I can't say I've had the same experience that you had in your chicken coop.


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## Jim-mi (May 15, 2002)

"his batterys ran down too fast" . . . . . .Then he's got other problems.

Or was "he" trying to extract *12 gallons* out of a *ten gallon* tank. (batt bank)

Or was "he" using cheap *car* batterys . . . . .

The only argument for mod sign over sign wave is the allmighty buck.


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## mightybooboo (Feb 10, 2004)

Ive had good luck with my cheapy Xantrex inverter in the Motorhome.Got it for 80 bucks,I think its 1100 watts?


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## Nevada (Sep 9, 2004)

mightybooboo said:


> Ive had good luck with my cheapy Xantrex inverter in the Motorhome.Got it for 80 bucks,I think its 1100 watts?


I don't consider Xantrex a cheapy brand at all. They bought-out Trace, which has a very good name in this kind of gear. If you got an 1100 watt inverter for $80 it was a great deal, regardless of brand. For a Xantrex, it was a steal. You can easily double your money simply by unloading at eBay.


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## mightybooboo (Feb 10, 2004)

No,not cheapy brand at all,cheapy price.Costco used to stock them a few years back.


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## Explorer (Dec 2, 2003)

I bought a 1000 watt Xantrex mod sine inverter early last year for about $90 and then a 1500 watt one late last year for $110. Use both daily and am happy with their performance.


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## mightybooboo (Feb 10, 2004)

Nevada said:


> I don't consider Xantrex a cheapy brand at all. They bought-out Trace, which has a very good name in this kind of gear. If you got an 1100 watt inverter for $80 it was a great deal,


Yes,and bought Heart too.

I read IIRC that Outback was started by former Xantrex employees not happy with where Xantrex is going.At least I *think* they were from Xantrex,cant remember for 100% sure to swear to it.


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## Jim-mi (May 15, 2002)

Yes boo boo, It goes back to the days of Trace before Xantrex bought them out. The story gets a bit complicated. A whole bunch of engineers left Xantrex and created Outback. . . . GOOD equipment.
And then another top dog engineer broke off and created Midnight Solar.
At the MREA energy fair, boB G. was showing his new, soon to be available, Classic MX60 charge controller. . . . .GOOD stuff.
Yes thats the way he spells his name--boB

I have a old Trace 2012 beefy mod sign inverter in a seperate system out in the barn. Runs all the power tools out there ....except the big air compressor.


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