Main difference between cheap normal inverters vs expensive grid tie inverter?

[unseengundam]

There seems to be big price difference between grid tie inverters and normal inverters. I can get normal 5000 watt inverter for less than $500 (running at 240/120v at 60hz for USA). Meanwhile, Grid Tie inverters for 5000w range from $2000 to $5000!

Only 2 difference I know of seem pretty simple:

1. Match / Sync to Mains (Electric Grids) AC voltage and frequency
2. Shutoff inverter if there is power black out from the grid

Is there any other big differences?

I honestly don't see why grid tie inverters are 4x to 10x the price. Matching to grids Voltage/frequency can be done by buying correct "cheap normal" inverters. While, you should be able to build a relay switch easily to handle the black out scenario #2.

Also, is there any way to expand features of cheap normal inverters so they can match features of the grid tie inverters? I think that would be more cost effective than buying dedicated grid tie inverters.

[sensij]

Do not forget the DC side of things... the grid-tie inverter operates the panel array at high voltage (typically 300-500 Vdc) and power. The MPPT algorithm helps control the panels to produce as much power as they can. I am unaware of a non-grid tie alternative that will handle that voltage and power, especially at the very high efficiencies obtained by this generation of inverters.

[Raul]

And probably a 5kw inverter for 500 bucks is going to pack up within 2 years and also the sine wave quality may be questionable.

[peakbagger]

Grid Tied inverters have to have built in safety protocols to make sure that they don't put power into a grid when the grid is shut down, they also need to match the frequency of the grid. There are inexpensive modified sine wave inverters that are quite cheap, most supply a very poor quality approximation of a sine wave and beat up some equipment. Their efficiency is generally poor and their ratings are quite optimistic. Some are quite amusing seeing a 12 volt inverter with 5,000 watt rating. Many do not even have large enough lugs to handle 1,000 watts let alone 5000 watts. There is also a issue of build quality and warranty coverage.

[mapmaker]

I can get normal 5000 watt inverter for less than $500 (running at 240/120v at 60hz for USA). Meanwhile, Grid Tie inverters for 5000w range from $2000 to $5000!

Can you provide a link to the $500 inverter? I suspect that the $500 inverter you are looking at is a piece of junk and does not have UL certification. You are probably comparing it to a quality UL certified grid-tie inverter.

--mapmaker

[lkruper]

There seems to be big price difference between grid tie inverters and normal inverters. I can get normal 5000 watt inverter for less than $500 (running at 240/120v at 60hz for USA). Meanwhile, Grid Tie inverters for 5000w range from $2000 to $5000!

Only 2 difference I know of seem pretty simple:

1. Match / Sync to Mains (Electric Grids) AC voltage and frequency
2. Shutoff inverter if there is power black out from the grid

Is there any other big differences?

I honestly don't see why grid tie inverters are 4x to 10x the price. Matching to grids Voltage/frequency can be done by buying correct "cheap normal" inverters. While, you should be able to build a relay switch easily to handle the black out scenario #2.

Also, is there any way to expand features of cheap normal inverters so they can match features of the grid tie inverters? I think that would be more cost effective than buying dedicated grid tie inverters.

I believe it is also required to be UL approved.

[SunEagle]

unseengundam

I beleive all the previous posts should provide you with some idea as to why there is a large cost difference.

In a nut shell, The cheaper unit is not:

UL listed and allowed to be used in the USA,
Contains the required safety protocols to disconnect or sync with the grid,
Is made in a factory that has a good quality assurance program to keep defective units from being sold resulting in a short life,
Does not have the same terminal and DC voltage input ratings,
Does not produce a true Sine Wave output,

Also anyone that thinks they can modify one of those cheap units still will not be able to use it in the US because even if upgraded will not have the required UL listing label.

[unseengundam]

Can you provide a link to the $500 inverter? I suspect that the $500 inverter you are looking at is a piece of junk and does not have UL certification. You are probably comparing it to a quality UL certified grid-tie inverter.

--mapmaker

Here are two, one looks to be UL listed:

http://www.amazon.com/Xantrex-XPower-Inverter-Remote-UL458/dp/B004JQ60OG/ref=sr_1_3?s=electronics&ie=UTF8&qid=1437510715&sr=1-3&keywords=inverter+ul&pebp=1437510722704&perid=0MJV2V4QA8AKQS8J0H70

http://invertersupply.com/index.php?main_page=product_info&products_id=2348&cPath=0_428&gclid=Cj0KEQjw27etBRDA3-ux4p3c58EBEiQAkJzTAOtlKASBRgylsZPTHJZ7rCUXh71Vzx_KMZcKkYGlTGIaAvrX8P8HAQ

[peakbagger]

For Grid tie its got to be UL 1741.

5000 watts /12 volts = 416 amps. Now look up the size cable you need.

[mapmaker]

Here are two, one looks to be UL listed:

http://www.amazon.com/Xantrex-XPower-Inverter-Remote-UL458/dp/B004JQ60OG/ref=sr_1_3?s=electronics&ie=UTF8&qid=1437510715&sr=1-3&keywords=inverter+ul&pebp=1437510722704&perid=0MJV2V4QA8AKQS8J0H70

http://invertersupply.com/index.php?...TGIaAvrX8P8HAQ

The Xantrex unit is NOT UL listed for hard wiring in a residence. I'm not familiar with that unit so I can't speak to its quality.

I would avoid any Aims products... they tend not to be high quality devices.

--mapmaker