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External limiting an GTIL2 SUN-1000G2 with raspberry
So both the 240v and 120v gtils work and do supply power, just no where near as efficiently as split phase inverters. So for me I think that sucks lol, that's going to really raise the cost of this installation on my house.probably going to make it cost 40 percent more now, but I guess since the system will be more efficient it probably would pay off in the long run
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Well right cuz your grid usage doesn't show individual legs, So your putting 2 more cts on on your main? Won't that show the same thing that the cts on your mains already show?

Which is that they are getting fed equally by the inverter to each leg, so then also that would make the usage from each leg the same cuz it over feeds one leg and under feeds the other leg by the same amount, I guess the cts u plan to put on would show that u are actually do have loads that are differnt-not so close on each leg but only if the inverter wasn't equally out the loads of the legs, so u would have to disconnect the inverter to see what your legs would actually use from the grid, if the inverter wasn't in play, but once u hook up the inverter then with cts on your mains or on your power wires from inverter will show equal usage-supply cuz the inverter isn't split phase so it supplies equal watts to each leg and again therefor overfeeding one and underfeeding another
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Using the example of 350w getting supplied from inverter to each leg, 500w load on one leg and the 200w load on other...So if (I don't know how it would be able to do it) it wasn't backfeeding the 150w on a leg that's getting 350 but only needing 200w from inverter then your load from each leg would be different-not so close and your supply from inverter would then be differnent but ofcourse that cannot happen because the inverter supplies equal watts to both legs cuz it straight-single phase 240 and doesn't have a transformer like split phase inverters typically do

So I guess I'm saying where would the extra 150w go if it wasn't backfeeding on the leg that was only needing 200w. The inverters producing 350w each leg so it has to go somewhere and backfeeding would be it's only path

Unless ofcourse somehow the inverters can send differnt watts to each leg which doesn't make sense for single phase or straight 240

And as your graph shows it's sending same watts to each leg so that can only mean it's backfeeding 50% of the difference that the 2 legs are using. So 500w load on one leg and 200w load on other leg would mean it's backfeeding 150w....if it was 400w load on one leg and 300w load on other then it's backfeeding 50w.....if it was 350w load on one leg and 350w load on other leg it would backfeed 0w.... and that's what we are going for close to zero watts backfeeding but actual loads on each leg are hardly ever perfectly equal so it's for the most part always backfeeding...this get worse when let's say u have a 2000w inverter and one leg has a load of 1600 watts and one leg has a load of 200w, then it would be backfeeding 400w!!! And only actually producing 900 for the leg needing 1600w for its load.

But the inverter screen isn't seeing what's actually happening it's just supplying the full 1800 watts and doesn't care were it goes it just puts it out equally thru each wire

So also then with the last example (1600w load one leg 200w on other leg, 900w supplied to each leg from inverter) it's letting the grid-power company supply 700w to the leg that's asking for 1600w cuz 900w is getting supplied by the inverter to that leg and the other leg is backfeeding 700 watts cuz it's getting feed 900w but only needing 200 for the loads it has

So with that example the inverter is producing 1800 watts...700 of that we would pay for cuz it's getting backfed on the one leg like I explained above, and 700 watts is what the inverter is letting the grid supply on the leg it's only supplying 900w too of the 1600w being used on that leg. So that's 1400w that we are paying for and or letting the grid supply to us - we pay for. So really with these loads in this example we would only be taking 400w off of our electric bill, NOT 1800w as the inverter is trying to tell us it's saving off our bill

Now Ik loads are not usually that different on each leg but the point is split phase inverters would supply the full 1800w to each leg (1600 to one and 200 to other) not just 400w like apparently is what the gtils this forum is talking about would actually be doing

the difference in how efficient these gtils are using them in America vs a split phase inverter is HUGE from what I'm discovering
What made me really think into this and figure it out is ofcourse because I want to install solar on my house but also cuz I seen a video of a guy with like 14 panels-grid tie producing just about enough electricity to power all his needs (using an inverter like sunny boy split phase) and then I also seen a video-talked to a fella with like 14 panels and he only produced 50-80$ off his electric bill (using the blue gtils) and the above examples now explains to me why they were producing such differnt dollar amounts
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Again about the cts, I bet the one that's showing a negative reading (ppl tell them to flip the Ct) is actually showing backfeeding to the grid, I'd say the negative reading is showing cuz of the leg that doesn't need as much power as the other leg but is getting supplied with the same power as the other leg, just speculating tho, as I read wolfs post and like I said idk enough about the way cts work

Btw did u get that Honda fixed up wolf?
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Quote:Doin it wrote,
Well right cuz your grid usage doesn't show individual legs, So your putting 2 more cts on on your main? Won't that show the same thing that the cts on your mains already show?
 No because the 2 CTs on the mains right now just give the GTIL2 its information on how much power is flowing into the house. I have no way of graphing that. As soon as I get the 2 additional CTs installed on the mains I will be able to graph that on the IoTaWatt and correlate that with the GTIL2 output. So I will be comparing the "Grid" usage compared to my GTIL2 output on each leg.

The Honda did well but boy did it need that timing belt!
25 degrees F this AM I hope by noon to be able to dig. Smile

Wolf

(03-24-2019, 06:27 AM)Doin it Wrote: Again about the cts, I bet the one that's showing a negative reading (ppl tell them to flip the Ct) is actually showing backfeeding to the grid, I'd say the negative reading is showing cuz of the leg that doesn't need as much power as the other leg but is getting supplied with the same power as the other leg, just speculating tho, as I read wolfs post and like I said idk enough about the way cts work

No the negative reading is because that leg is 180° out of phase from the other CT so they cancel each other out that is why you get a negative reading. 

Wolf
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Great prices and superb service.
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If they cancel each other out then wouldn't it read 0

Wouldn't sometimes with the cts both the same way it wouldn't always read negative or 0 or positive depending if that leg is getting backfed like I explained above

I think ppl are just telling ppl about the out of phase stuff cuz these inverter are really meant to only have one Ct cuz the inverters aren't meant to be supplying 2 legs cuz they are single phase inverters

Wolf I think your cts u are going to put on will say your usual is equal with the inverter hooked up

Usuage*

Cuz of the examples above

Cuz the inverter backfeeds on the leg with the lesser load and underfeeds that same amount on the leg with more load

Unless somehow the inverter can split the wattage it's supplying to each leg but I don't think this is possible with a single phase inverter that doesn't have a transformer
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or maybe ( but I done think so) the cts u are putting on will show differnt loads on the legs which then mean the inverter is not backfeeding or the cts can't read current-power going both ways, can they?
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And the answer is................ Sad
The GTIL2 with 2 CTs does backfeed to the grid.
Ground still frozen but ran wires anyway.
Pic 1 shows my consumption from Grid with GTIL2 shut off.


Pic 2 shows my consumption and the output of the GTIL2 notice the neg reading on the L2 which indicates I am feeding the grid.



Bummer dude, I guess I'm going to have to get a second GTIL2 1000 so I can split the legs as the 2CTs in parallel do not work according to the figures that I see.

I will let this graph run for today as I got to roll up the cables tonight but you see the green line drop when I shut down the GTIL2.
And the Blue (L2) picks up. But once the GTIL2 is turned back on it shows that there is negative flow on L2 meaning it is feeding the grid. On L2 anyway. 
I will post the days graph when done.

 



Doin it Wrote,

or maybe ( but I done think so) the cts u are putting on will show differnt loads on the legs which then mean the inverter is not backfeeding or the cts can't read current-power going both ways, can they?

CTs can read current going in either direction. Hence they have an arrow on them so you know the orientation.

Wolf
For Info Google Drive

Great ABB shunt breaker seller River City Industrial
Great prices and superb service.
 [Image: em2566%20(1)__19172.1521541365.jpg?c=2]

Not your average Wolf       
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Dam that suks, I was hoping it wasn't this way

If u have 2 1000w gtils on seperate legs the got to be 120v models not 240v models correct? Otherwise u would be feeding 240v to the grid

I meant if u had 2 240v inverter on separate legs then each 120v leg would be supplied with 240v, I'd suppose this isn't good

So installing one 240v inverter does exactly what my examples say above (give or take a few watts) but basically. So 240v gtils installed on the USA split phase panels is horribly inefficient compared to single phase inverters?

Compared to split phase inverters*

So your graphs say that both legs are calling for a total of 780w and the gtils is supplying roughly the same at 757w and supplying that equally to each leg at roughly 375w for each, so then it's overfeeding-backfeeding the leg with only 232w load by roughly 180w which the digital meter makes us pay for, and the other leg with the 548w load is getting underfed by rouphly 180w which then our power company supplies us with which we pay for.? So this is the same as my examples above I believe

Wolf also I believe if u flip the Ct back to the position that it was showing negative that it will show the same negative-backfeeding that your graph would show

Also the more uneven the load of tour legs are then the more it will backfeed

Your* not tour
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The reason you are having the Odd ball reading is because Both your Ct"s are the same direction. On Single Phase 240 feed One is Normal arrow pointed toward the Meter and the other pointed toward you breaker panel.
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