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External limiting an GTIL2 SUN-1000G2 with raspberry
So on the gtil forum they are saying that if I don’t have batteries I don’t have to limit the watts. Seems not good to let the inverter get to max, but a lot of ppl have been doing it for yrs with an oversized array and not limiting watts in the settings. I want 2 more panels so I get more watts on cloudy day. My panels are series and parallel. 33v each, 66v total, 9amps each , 27amps total. With 2 more panels my volts will stay the same but my amps will raise to 36
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(04-30-2019, 01:36 PM)Doin it Wrote: So on the gtil forum they are saying that if I don’t have batteries I don’t have to limit the watts. Seems not good to let the inverter get to max, but a lot of ppl have been doing it for yrs with an oversized array and not limiting watts in the settings. I want 2 more panels so I get more watts on cloudy day. My panels are series and parallel. 33v each, 66v total, 9amps each , 27amps total. With 2 more panels my volts will stay the same but my amps will raise to 36

Quote: I want 2 more panels so I get more watts on cloudy day
Got it sounds good. I guess if the forum says don't limit then its up to our personal discretion.
I have mine set to 900 Watts each which seems to work out perfect.
Caught this pic while the sun was out and very happy with the results. both L1 and L2 are independent of each other.
Also with 1 GTIL2 1000 I would have never been able to get over 1kW of production. Of course you have the 2000 Watt version.
Note: I have seen both combined outputs as high as 1.8kW but just for a short period of time.
Wolf
Solardad likes this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
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They say u don’t have to limit inverters max if u power with solar directly. But with batteries yeah it’s a necessity

Cool man I’m glad the 2 inverters are working like u want
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(04-19-2019, 08:40 PM)Wolf Wrote:
(04-19-2019, 08:13 PM)Doin it Wrote: Wish we woulda figured that out sooner, I already bought the 240v version and it’s hooked up and running. I think my loads are balanced fairly well tho.
So wolf how did u wire to your breakers?  Are u running the inverters at 120v now instead?

I am running them at 120V each with CTs for each one individually. Same breaker 20 Amp 240V. Obviously 1 GTIL is on L1 and the other one on L2 Working great.
Check out my emoncms.org dashboard https://emoncms.org/dashboard/view?id=53517
Also you can check out my Grafana dashboard on my home server. Got to log in though as guest and password is guestw
http://wolftech.mynetgear.com:4562 

Wolf

Hi Wolf - Dashboards look great!.

I think you leverage have a battery bank with your system..?.? Have you tried to measure / monitor the voltage of the pack with Iotawatt? I am thinking of setting up a similar monitoring system. Thanks
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(05-07-2019, 09:58 PM)Solardad Wrote: Hi Wolf - Dashboards look great!.

I think you leverage have a battery bank with your system..?.? Have you tried to measure / monitor the voltage of the pack with Iotawatt? I am thinking of setting up a similar monitoring system. Thanks

Thanks Solardad

Ah the monitoring of Battery Voltage yes that is an issue. Unless I am missing something really obvious The IoTaWatt only does CTs and 1 Voltage input for line AC which is supplied by a calibrated Transformer. I just 2Xed it to get my 2 phase V of ~240.

The Emon system seems to allow for battery V measurement with their system I think.

For battery voltage measurements I am in the pre breadboard stage and collecting parts. I will be using an Arduino to measure Battery V using a V divider and a Shunt to give me my Amps to and from the battery. Once that is accomplished I hope to send the data over wifi to my local influxdb and be able to chart it. I am watching and learning a lot about how to do it and if successful will publish here. I still have to figure out all this about ESP32, ESP8266 etc etc  C++ AT commands and so on. Ha I remember AT commands from my modem days to get on to the internet.
On another note once I get my Li-ion packs built I will more than likely get a Batrium system and I believe then that info can then be ported to my influxdb.

Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
For Info Google Drive
Not your average Wolf       
            Cool



Reply
I’ve figured out how the fella on eBay makes the dual CT cables. So if anyone is interested let me know. Also wolf I have figured out why exactly we have to flip one of the cts with the 240v version. Makes perfect sense now as to why the 240v inverter does not backfeed as long as main panels loads are not more than 75% different leg to leg
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(05-09-2019, 12:47 AM)Doin it Wrote: I’ve figured out how the fella on eBay makes the dual CT cables. So if anyone is interested let me know. Also wolf I have figured out why exactly we have to flip one of the cts with the 240v version. Makes perfect sense now as to why the 240v inverter does not backfeed as long as main panels loads are not more than 75% different leg to leg

Excellent yea I also took the CTs wiring apart and found a resistor in there. Didnt look any further though as I was busy hooking up my 2nd GTIL.
Its sitting on my bench for further study when I get a round tuit. Tongue

So since my mains had a greater than 75% difference between the 2 legs I was having issues. Makes sense.

Wolf
aminet likes this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
For Info Google Drive
Not your average Wolf       
            Cool



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(06-14-2018, 01:14 AM)Stephen Krywenko Wrote:
(06-13-2018, 10:25 PM)watts-on Wrote: Yup, that's exactly how I was going to do it. So you already have a project doing that with PWM? Why are you wanting to change to the digital pot method?

my arduino code uses both Pot and PWM already  I am not really changing anything - PWM are for firing  SSR or TRIAC  for diversion. the pot code was for adjusting  DC motor controller that adjust the  dc input to the   GTI to reduce it power output from solar panel.   but  now  i wanted to do large power wall application and i bought these sun 1000g2 to work with the lithium batteries I bought.  so I am going to adjust my code and my infrastructure to work a little  differently .     but not sure how it will all play out , i ordered some 5 k digital pot  will be able to handle 2   sun GTi on each to play with.. I will find out in couple weeks time  when they arrive . and i start trying in different methodologies  and see what works best for me..

So did the digital pot work to control a linear output of the power? Would this work on the 2kw version too?
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Got distracted for a while and catching up with this thread.

I surmise the 2000W GTIL works on 240V solely because 120V circuits tend to be rated for no more than 1500W. Pushing 2KW in a circuit that supports 1.5KW is a bad idea.

Most smart meters have a single current transformer loop. It counts power consumption by summing the L1 and L2 legs out of phase with respect to neutral. A dual transformer loop can measure power and direction on each leg separately, but it costs more, so it’s not common.

Yes, the utility company can see what was returned to the grid if the smart meter has an accumulator for power ‘generated ‘ even if there is no indication of it on the display. My Silverspring meter logs KWhr in both directions as separate counters.

Be careful of the GTIL hooked up across L1 and L2 with the CT on either leg. It will correctly measure 240V loads and feed the correct amount of power, but, 120V loads on either Leg with respect to Neutral register as 2x the actual load since The GTIL has no reference to what return current on neutral is. Example...if the house is drawing exactly 10A @120V on L1-N and 0A@120V on L2-N, the gtil The gtil sees 10A between L1-L2 @240V = 240W. Thus the extra 120W backfeeds to the grid

The only way it will work is with the addition of a 2nd CT clamp on either the other leg or neutral. The current on the 3rd line can be calculated.

Wolf’s setup with a single battery bank share between two gtil works because mppt does not apply to pulling power from batteries.. Sharing a common PV bank probably doesn’t work very well as the mppt engine on each gtil will confuse each other’s readings on the PV measurements.

I’m curious to know if anyone has tried it to see how bad it really is. It might be a small sacrifice for unbalanced lines. Eg., If i have two identical 1000W arrays on two gtil’s , each on its own 120V leg, one gtil can potentially be running 1000W and pulling 1000W from the grid while the other is doing nothing
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aminet,
I am posting your answer to your PM to me here as you have PM disabled in your user CP.

I will double my efforts to get the info to you and take a picture of the setup of the CT's with the resistor.
But in the final analysis it may help some but the truth is with a single phase 240 GTIL you will always feed back to the grid some no matter what.
The CTs no matter how they are combined will always feed the highest current consumption value to the GTIL which will respond in kind.
If you are pulling 500W on 1 leg and 250W on the other your GTIL will produce 1000W (500W on each leg) overfeeding the 250W leg. You can see that in the charts I published in this thread. Think of a 240V single phase sine wave.
The up wave supplies 500W and the down wave supplies 500W. If you where running single phase no problem but with split phase you are feeding 2 separate channels with the same power.
That is why I went with 2 1000W GTIL each with their CT on their respective leg and I have absolutely no feedback to the grid.
Wolf
aminet likes this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 6/10/2019
Total Number of Cells                          5940
Cells  >80% of Capacity                      4334
Cells <80% of Capacity                       1605
Cells ≥2200mAh & ≥ 80% & ≤75mΩ    2800 +236
For Info Google Drive
Not your average Wolf       
            Cool



Reply


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