| Author |
 Topic  |
|
|
BushWhacker
Junior Member
Canada
325 Posts |
 Posted - 19/01/2008 : 18:51:43
|
I'm just doing a little research concerning inverters and am wondering about the real life differences behind a Pure sine wave and Modified sine wave inverter.
Xantrex offers a DR1512 1.5 kW, 12V inverter for $695 (Roughly 350 Pounds) and says " By converting 12-volt power to clean AC, the DR1512 can run most common tools and appliances, including microwaves, refrigerators, hand tools, televisions and computers. ".
Outback offers the 2 kW, 12V, true sine - sealed for $1895 (Roughly 950 Pounds)
I know I'm comparing apples to oranges to some extent, but with a near triple in price for 1/3 more power I would certainly hope there are major advantages to picking the Outback inverter over the Xantrex inverter. It would seem that computers and electronics are the focus of pure sine wave inverters, but is it really that important or will a modified sine wave inverters output go unnoticed by the more sensitive electronics found in a modern home?
Any input would be appreciated as I am just starting to learn a wee bit about inverters.
Thanks,
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein
|
|
|
Del
Junior Member
United Kingdom
369 Posts |
Posted - 19/01/2008 : 22:52:30
|
Hi BW,
I've got a modified sinewave inverter but want to get a pure sine one at some point. The modified sine inverter, as far as I have read and partially experienced, will operate any appliance but as it doesn't quite match the normal electricity grid type wave you get some interference in the form of slight buzzing and/or slight interference on TV and computer screens. I've also read that modified sine inverters aren't great with flurescent lighting.
I have found this on my kitchen TV so don't use it to run a TV now.
It's a shame really as pure sine inverters are expensive and usually less efficient than their modified sinewave equivilents.
There seem to be quite a few pure sine inverters available on ebay from the far east, but I'm not sure about them. Anybody got any experience?
Cheers
Del. |
 |
|
|
ghurd
Junior Member
USA
313 Posts |
Posted - 20/01/2008 : 02:43:52
|
I know a couple people happy with Samlex pure sine waves. 1500W, ~$550.
http://store.solar-electric.com/inverters.html
I know of a few people happy with pure sine Exceltechs, though they are a step smaller than what you are talking about.
I don't own a pure sine any more. Never had a need.
The only items I personally ever saw that would Not work with mod sin was a couple models of high end Craftsman cordless drill chargers.
The chargers smoked.
Makita chargers can be picky. Same model chargers, same model inverters.
Charger A won't work with inverter B. Charger B won't work with inverter A. Charger A & B work with inverter C.
Very rare. Nothing blew up.
Like Del said, maybe some buzzing, maybe.
And given the pure sin is less efficient, I would have a large mod sin, and a small pure sine.
More efficient. Less expensive.
Most bigger items don't seem to mind mod sin.
Depends on if you will feed the whole house from 1 inverter.
G-
|
|
|
|
Gill
Starting Member
Australia
42 Posts |
Posted - 20/01/2008 : 03:52:14
|
G'day BushWacker,
Like Del, I too run a modified square wave inverter and have done so for over 10 years using it as my sole source of 240v. Some of the appliances in regular use are TV, water pump, numerous desktop PCs and laptops, multiple fluorescent lighting, numerous plug pack adapters, washing machine, electric fans, medium refrigerator, soldering irons and lab power supplies. Many other appliances such as hair clippers etc. get less frequent use but I won't list them. My point is that a QUALITY modified square wave inverter can be used to live by.
I was having trouble with my oscilloscope showing the inverters switching transitions on the trace so decided to go to a sine wave inverter thinking this would rectify the problem. It did not, in fact the trace was totally unreadable. Marketing states a pure sine wave , don't be fooled, it is far from pure as the trace of it's output is very jagged causing unreadability of the scope. In addition to this, the radio interference was over many bands and although this was a quality and certified RFI free device, it was not possible to use several bands from HF to UHF. And this was running the transceivers from an independent power source @ 15 meters from the inverter with nothing plugged into the inverters power outlets. I was most disappointed and returned the device for a refund and went back to using the square wave.
Having ****-canned the sine wave, let me say that the modified square wave has not been without it's problems. I had a washing machine that would not run on it, a small air compressor that will not run, two domestic pedestal fans that burnt out and a computer monitor that develops chunky horizontal lines. I've had no problems with fluorescent lighting though.
With my experiences I am of the opinion that Mains Power is best and cheapest, Sine Wave is next best providing you buy quality and don't have appliance specific conflicts, and Modified Square Wave least desirable but still usable provided the rated output well exceeds the total usage and is of Quality.
Many cheap Chinese manufactured inverters are appearing in my country and are of unknown quality and I guess there appearing elsewhere too.
If you had a VW and put a Porsche motor in it, do you now own a modified Porsche or a modified VW?
If you had sine wave why the hell would you want to modify it to what they say is the modified sine wave profile. I get on my soap box when 'Marketing' lies to the consumer presenting what is a square wave that has been modified to closer resemble a sine wave as being a 'Modified Sine Wave' . Utter bull ****. Step down of soap box.
I guess what you buy depends not only on suitability but also on budget, and that's a decision only you can make, still I hope sharing my experience is of some benefit.
Good luck.
Cheers... Gill |
|
|
|
mark e
Starting Member
United Kingdom
22 Posts |
Posted - 20/01/2008 : 11:54:10
|
Bought a 150 watt inverter from Maplins, not pure one, and i have tested a few products i have to run in my motorhome. One thing it wont run is a portable cd player. Power just turn on and off, but tv's, portable DVD players are fine !
------------------------
No Ifs...No Buts... |
|
|
|
BushWhacker
Junior Member
Canada
325 Posts |
 Posted - 20/01/2008 : 21:22:02
|
Great replies people! It's always best to get opinions from product users in my opinion, and you folks have come through in spades. Thank you!
The cordless power tool battery chargers comments surprised me as I have a 75 watt inverter that plugs into an automobile cigarette lighter socket and charges Makita batteries flawlessly. I also use it to power a portable stereo (boom box) with a CD player, and that works like a dream as well. The inverter was bought on sale for about $30 or $35 so I would hardly call it "high end". Rather perplexing???
From what you have written, with my applications and expectations I guess I have to go with pure sine wave and a couple of 110 volt AC inverters as I wish to run some 220 volt AC tools as well. I'm sure not having to replace "melted down/up in smoke" items will help offset the premium price.
I have also read about some inverters that have a power saving "sleep" mode when there is no load, and search for load a few times a second. I'm sure this would offset some of the inefficiency of pure sine wave inverters.
In short the bank account is going to take a BMW beating cause a Lada just won't do. Thank you all for your input cause I really didn't know if the extra expense was justified.
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
|
|
|
BushWhacker
Junior Member
Canada
325 Posts |
|
|
ghurd
Junior Member
USA
313 Posts |
Posted - 22/01/2008 : 05:02:11
|
Hold on! You can not connect two 110V inverters to get 220V.
Unless they were designed to do it.
Rare, but I recall there was a brand or 2 that had a model or 2 that did plan for that.
G- |
|
|
|
BushWhacker
Junior Member
Canada
325 Posts |
Posted - 23/01/2008 : 00:34:15
|
I caught that ghurd but have read about at least two brands that advertise that feature.(220 volt) I'll make sure I see it in writing and print it out BEFORE I buy units with this application in mind. Then I'll pray for a wind storm on the days I use 220 volt items.
All the same thanks for the 'Don't zap yourself' warning. I'll have an experienced journeyman electrician do the install as well with documentation to back it up.
ghurd, have you given any thought to designing a heavy duty charge controller?
Would you recommend just using multiples of the one you have already designed?
Sorry about the slow replies but I'm cramming a bunch of courses into an insanely short period of time to launch a new career. In another month and a half I'll be fit for a mental ward, but should recover within a month or two after that. Then it's moving time and start up of the solar/wind adventure!
Again, thanks to all of the contributers! You have been down this path and I will gladly learn from your experience. It's a heck of a lot cheaper that way!
Cheers!
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
|
|
|
ghurd
Junior Member
USA
313 Posts |
Posted - 23/01/2008 : 17:24:05
|
My design can add more fets to dump more power.
Then they can be staged too. Like a couple set at slightly different voltages.
There is no real limit to what it can handle, with enough fets.
There comes a time when it would be worth getting something with 3 stage charging, like a TriStar.
On the other hand, big-money controllers seem a bit silly if the rest of the system cost less than the controller!
G-
|
|
|
| |
Topic |
|
|
|
Pure or Modified sine wave inverter.
