DC to AC inverters poll

Hi,

I can't decide whether to go for a more expensive pure sine wave inverter or a cheaper modified sine wave inverter. As my Toughbook will likely be the most sensitive equipment charged with it i hope you guys could share your experience with either one.

Best regards

 

For what it's worth; I found that the pure sine wave works best with boat electronics.

 

ABD,
What are you using the AC for? If you just want to run your toughbook get a Lind power supply on eBay. 12v to 15.6v, about $25 if you look hard, much less drain on your battery, blah, blah. Inverters are much less efficient and the cheap ones aren't very reliable.
Cap

 

I've used both...

On the bat we havea true sine wave for general use..Mostly because of the noise produced by the cheaper inverters, I don't need to put up with the RF noise!

Having said that, I do have a cpl of smaller (the true sine wave is 1800watts) inverters that are used for small tasks... I keep a 400 watt one in the car for the occational use where RF noise isn't a problem..And the wife has a small one for her sewing machine...

73
Semper Fi
ed

 

thanks for the replies, i can see the sense in using a DC to DC adapter but i'm thinking of installing an inverter so i can use it with other items (battery charger for camera, another laptop, different phones and probably others i've not thought of) also i'll be off on a trip with a friend that has a mid priced modified sine wave inverter and i'm wondering of it's safe.

I've seen varying opinions on this issue but mostly it's sellers of pure sine wave inverters naturally scaring me into spending. I did have a slight problem with a laptop about 10 years ago, it all seemed to work still but after using a cheap mod sine inverter a charging light stopped going out after fully charging up when plugged into mains, i didn't get to the bottom of it or find it caused any actual problem but it did make me wonder if there really was something in it.

And i didn't know the true sine wave inverters create less RF noise so that's another reason to spend more

cheers

 

If you are going to use a real Panasonic charger I believe it will protect your computer from any problems the inverter might have. Any issues with the cycles should be filtered out by the adaptor which puts out DC, no cycles. I believe the only issue with inverters is when you are using something which relies on the cycles for timing. I THINK!

 

Exactly.

The power supply should filter out any inpurities and/or noise on the AC line.

Pure sine wave is good for synchronous AC motors used in clocks and turntables.

Most other electronics will actually downconvert the incoming AC to DC and have a built in timing circuit. (Think how cheap and accurate quartz digital watches are... Timing oscillators are everywhere.) This makes sure electronics maintain correct timing despite going into a home electrical system. (With large motors such as in the Air Conditioning, Fridge, and laundry machinery that produce ElectroMagnetic Interference and Microwave ovens and other household radio transmitters producing Radio Frequency Interference.)

Also note that Laptops are designed to travel, the Toughbook especially, to foreign countries which may or may not have the greatest quality electrical service.

APC's Back-UPS series of UPSes uses modified sine wave inverters. We all know APC is a popular brand name.



You'll be fine with a modified sine wave unit.



I'd only run a modified sine wave unit if I were running the previously mentioned motorized equipment... I might think about it if I were dealing with radio communications gear, sensitive test equipment (Oscilliscopes, Spectrum Analyzers, Tracking Generators/Sweep Oscillators, etc.) or medical equipment. But I wouldn't bother too much with finding a pure sine wave inverter if I didnt have one.

 

thanks again, now my mind is suitably resting It is the original Panasonic adapter so i'll give it a go.

cheers

 

I have been using a Cobra 3000 watt modified inverter in my van for years. I used 6 gauge wire from the battry to inverter. I installed a heavy duty surge protected 8 outlet box, its plugged into the inveryer. I power my GPS, Cell charger, SureFire flashlight charger, laptop, all my cordless tool chargers. I have never had as much of a hiccup. I power my docking station with the Panasonic charger.
I believe you will be fine. If I was using anything with motors, then I would consider pure sine wave.

 

Even then, it's only speed sensitive motors.

Drill or saw, just fine. Might not be as efficient, but it'll still run.

I've never had to drill at hole at a certain exact RPM.

 

I guess I should have worded it better Pele. Alot of motors pull a surge when starting up. Such as a compressor, etc. You 1st would have to make sure you have enough power to get the 'start up' going. It's that start up draw where I would want good,strong,effiecent power. Pure Sine is more efficient.

 

Ah. Inductive loading.

Meh. If it's small, again, like my drill or sawzall, I'll run on the modified.

If it's large like an air compressor or something. I'd probably either have a Generator or directly hook a gas engine to the air compressor.


I'm actually looking for a small ~2500 Watt inverter for my tow truck and a 10-15Kw Generator that will run off the transmission's PTO connection. If I can keep the engine's idle speed stable enough to produce 60 Hz sine out of the generator, I'll go for a Modified Sine Inverter. If I can't then I'll go for a Pure Sine.

The tow truck is gonna get modified to be a mobile emergency communications base station. The winch will raise a ~150 ft tower (Stowed telescopically in 20 ft sections, rotated horizontally resting on the flat bed when down) loaded with antennas and radio gear will be in the cab.

 

Pele, I was going to ask what application or profeession are you in? But you hit that perfectly!

I have a 8HP 30 Gallon compressor in my van. It has a Honda engine on it so it runs like a champ. I am considering a generator myself. I would love to have one with the work I do. I invested some money in a company about 4 years ago that developed a system that runs off the vehicle's engine. I cant remember how many KW's it put out but it was nice. It is made for bigger, larger engines than what's in my van.

I really use my current inverter pretty hard. It's been perfect so far. I am wanting to hook up a dual battery system, but cant find the time lately.

Thanks for sharing your knowledge!

 

decided to make thread.

 

By day, I'm a Radio Telecommunications technician, working for the Washington Metropolitan Area Transit Authority. I maintain the D.C. Metro system's radio communication infrastructure.

My office usually is downtown at the operations control center, but can also be several hundred feet up at the top of a radio tower... Or several hundred feet below ground in a tunnel teetering over a 750 volt third rail.



I'm not a licensed mechanic, but I play one in my garage... Although seeing as how I couldn't afford a house with a garage, I really mean other people's garages... I'm a gear head. I offroad my Isuzu Rodeo (Actually Honda Passport, but they're the same machine underneath.) It'll get lifted when I learn to weld... I also race my Mazda RX-7, soon to get a roll cage, also after I learn to weld... (Damn this learning.) I worked at a shop, but hated working on cars for money, besides, it's bad on the joints. None the less, I own my own flatbed tow truck... For my own personal use. I find that just slightly... odd.


I'm a jack of all trades, master of none. It's kinda a necessity.

 

I can't help but ask... all this sinewave schminewave talk... whats the difference in what all u guys are talking about and going to best buy and purchasing a 500watt inverter that plugs in to your cigarette lighter in your car, cuz I have a 300watt one and I can power my toughbook and a cell charger or a 2nd laptop with it

 

The household power you get from an outlet is 120 Volts AC... AC means the power reverses direction every so often...

How often? 60 Hertz... No, not the car rental company. Hertz (Hz) means "Time per second." In the household power's case, the direction reverses 60 times per second. ( Segway! Skip if you want to stay on topic. You may note that MHz and GHz used in Processor clock speeds and Front side bus speeds contains Hertz... The clock ticks at this rate. Processors complete instructions in various clock cycles. There are also wait states where the processor is busy or not doing anything at all... Hence Clock speed is not the end all be all of ranking processors. Also note that bringing your Bus speed closer to your processor's native clock speed means that your processor will have less times where it's waiting for other components on the bus, IE RAM to catch up.)

Now the AC current doesn't just all of a sudden reverse direction... That'd be a Square wave... The voltage gradually drops to zero before becoming negative, then slowly rises to zero before completing another cycle. It follows a certain wave pattern called a Sine Wave... You can use the "sin()" function on a scientific graphing calculator to see a Sine Wave.

We use a machine called an oscilloscope to view voltage changes over time.

Here is one sixtieth of a second in Sine wave and Modified Sine wave:


Note the difference.


The thing is, producing inverters that will produce a perfect sine wave is VERY expensive. 300-500 watt inverters are around 150-200 US Dollars for Pure Sine Wave... Versus 30-70 US Dollars for a Modified sine wave... (That's probably what you're getting at Best Buy.) And the price difference climbs from there...



The thing is those sharp changes in current of the modified sine wave produce some heat, so the inverter is not as efficient...

There are also other pros and cons as we discussed earlier...

Basically, only use a Pure Sine wave inverter if you absolutely, positively NEED it, or are spending someone else's money... (Expense account, tax writeoff, government/taxpayer funded.)

Otherwise, a modified sine wave inverter will do ya just fine.

 

Thanks for the science lesson hehe

So long story short I'll stick to the normal inverter I have