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Power Inverter: Modified vs True Sine Wave

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So I'm shopping for a DC-to-AC power inverter for the van and am wondering about the Modified vs True Sine Wave power inverters.

I'm interested in...

Samlex True Sine Wave 1000 Watt inverter $427

http://samlexamerica.com/products/productdescription.asp?ProductsID=7018

or

Xantrex XPower 1000 $99 (Modified Sine Wave)

http://www.xantrex.com/web/id/23/p/1/pt/29/product.asp

...and I'm reading a lot of things about having problems running items like...

1. Microwave oven (doesn't run or the cooking time is extended)

2. TV (interference/noise)

3. Radio (interference/noise), I'm not sure if this has to do with running it off of the inverter or on a separate battery. I'm running off of a separate battery.

I'm not sure if I'll be running #1 or #2 in the short time, but it would be nice to not worry about it in the future. Wife wants to run a hair dryer at the minimum, which means I either have to find an inverter with more wattage or a lower wattage blow dryer (probably the latter).

I picked the above 2 because they both fit underneath the passenger seat.

So, what would you do? Thanks!

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I bought a Xantrex 2000 watter from Costco for $69! Best deal I have ever seen. Dont need true sine wave. The regualar inverters make pretty good AC electronically. My 2000 watter required 6 gaure wire to take full advantage of the power though. It will run a group 27 battery dead with a 1000 watt microwave in 27 minutes according to the brochure.

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Unfortunately, Costco online currently has one for $200 and only 1750 watts for 5 minutes.

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1000 watts for a microwave is too light, unless its the tiny nukers the size of a lunchbox. I would go no less than 1500 for a nuker, and then you may find that you need to unplug any other appliances to get full power from the microwave. You'll have to use heavy cable to get full power out of the inverter like ToyotaMDTTECH said.

My TV in the semi runs off 12v DC, and I have a 100 watt inverter for the laptop, and have never encountered problems with static/interference with TV, FM stereo, XM radio or CB radio. And this is a cheapy $20 inverter that isn't a sine wave.

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If you are using it for mainly home entertainment items like stereo and tv then I'd go with a true sine wave inverter. Anything else with the exception of certain chargers will be fine on a modified sine wave.

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Thanks guys for the replies. I finally decided on a modified version mainly for cost and fitment issues. The only thing I found that had the largest wattage to size factor was from Vector on their modified sine inverters.

I'm constrained to a 16"x9.5"x4" (LxWxH) area so at first I was going to get this 2000W...

http://www.directdepot.net/product_info.php?products_id=848

...but just remembered that I didn't include the battery connections, which would get too close to the max 16 inches length, so I instead opted for a 1500W...

http://www.directdepot.net/product_info.php?products_id=784

Hopefully this is a good quality unit, because I have no other choice. Thanks again!

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careful with that toyota. He could be trying to wire a 20' run.

I have a 2KW modified sinewave in my rv, and I can run everything from the tv's to the microwave to the laptop and the stereo without issue. I would not take that as an endorsement for modifieds in general, because the cheaper you go the higher the harmonics present in the a.c. output. It's the harmonics that kill your electronics.

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If you look at the picture below, my max length is 16 inches.

http://f3.yahoofs.com/users/41a8312az99678f54/cdd5scd/__sr_/43descd.jpg?phA7z8EBx5arXwZn

According to Vector, the 2000W inverter that I wanted had a max length of 13.75 inches. Another website, they have it at 15 inches. I can't find any dimensional drawings online so I don't know whether it's just the the body length or the body and battery terminals. Sometimes they only spec it for the body and leave out the terminals.

Let's say the terminals protrude out to 1 inch. That would give me an overall length of 14.75 inches, and would leave me 1.25 inches for the cable radius for the 4AWG wiring that they recommend. And the 2000 watter has 4 batt terminals, 2 for each +/-.

Too close, so I opted for the 1500 watter that has a length of 10 inches. It's a sacrifice, but I don't want to mount it any where other than underneath the seat. There's warning about mounting it near a battery, but there's a battery vent tube that exits below the vehicle. Hopefully that'll be enough.

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I have a 2KW modified sinewave in my rv, and I can run everything from the tv's to the microwave to the laptop and the stereo without issue. I would not take that as an endorsement for modifieds in general, because the cheaper you go the higher the harmonics present in the a.c. output. It's the harmonics that kill your electronics.

Which 2k do you have?

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it's a magnum energy ME2012-20b. The 2KW is rms watts, not peak watts. So you wont be stuffing this one under a seat. the wattage ratings on the cheap ones are just like wattage ratings on cheap car amps, total fabrication. But if the cheap one gets the job done then it's perfect for the job.

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Remember these things need airflow to keep cool. I use a xantrex from costco. (modified sine wave) It runs battery chargers (cell, laptop, etc) DirectTV, christmas lights, strobes, and a TV without any problems over the last 6 years.

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I don't know if putting it on top of that battery is wise, battery's need to vent, and and inverter can make MASSIVE amounts of heat. LOTS of airflow needed. My little 100w powering my laptop get damn toasty on its own. Large inverters have built in fans, and need unrestricted airflow, or meltdown is imminent.

If thats a seat base, or there is something that goes over that battery, your invertor will have a shorter life span than fruit fly.

Just my experiences, I've only seen 3 semis burn down from overheated invertors, and would hate to see you deal with the same heartache.

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The battery is not covered, surprisingly, and comes from the manufacturer just like that. There's a vent tube that attaches to the battery and through the floor of the vehicle. The only thing that covers everything that you see is the passenger seat cushion (missing from the picture).

If the chair is slid all the way to the front, the negative terminal is exposed to the cabin. The chair can also be raised or lowered to increase the air volume. The compartment is not completely sealed. There's large passages around the area that does not impede air flow from the cabin. There's only a 16x9.5x4in area that doesn't get touch by the movement of the chair; sliding, lowering, and raising.

However, you guys are right though. Mounting it in the location cannot be compared to mounting it in open air. Right now, with the power, dimensions, and brand of inverter out of the way, my last thing to do is to monitor the heat generated during idle and normal use. I'm hoping that the fan, chassis fins, and shutdown circuits will let me mount it there. I don't plan on using it heavily and will probably limit our usage or duty cycle initially.

My other option is to not mount it there which then brings other complications to the mix; longer DC wires, aesthetic reasons, etc. With any inverter and mounting location, I would still monitor the heat generated and duty cycle though.

Duly noted and appreciated! Thanks!

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Good deal seekman. I only use mine on heavy loads for short times (blender, hair dryer). Mine is under a sealed bench seat. Doesn't get much air.

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