The Greg's Grid Tie Solar Project

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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

johu wrote: Mon May 22, 2023 5:36 pm My 8.9 kW of panels do max out my inverter at 7.8 kW for a few hours over noon:

grafik.png

So it should be possible to get near 1000W from your. The angle seems pretty much perfect. I found that the "Grid Tie Inverters" don't do a good job at MPP tracking and also have poor efficiency. MPP of my one panel system here is 30V but the inverter runs it at 26V. That's 13% loss right there. Efficiency is about 85% for my 500W model, another 15% gone. So 28% losses in total almost line up with the 60% you calculated.
Prompted by your affirmation of the crappyness of grid tie inverters I decided to go stare at mine for a bit, and I am glad I did. A quick inspection showed that both of my DC leads, both the positive and negative were loose as a goose, not even hand tight. I tightened them immediately first by hand than further gently with some pliers. I can't wait to see what happens tomorrow, if that made a difference. One thing is for sure I will never use that installer again, what a hack !
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

now appealing to the short attention span audiences, cause who has two minutes to sit and listen to stuff about solar panelism these days

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Re: The Greg's Grid Tie Solar Project

Post by MattsAwesomeStuff »

Gregski wrote: Fri Jun 02, 2023 1:28 amnow appealing to the short attention span audiences,
You've had the panels up there for years, just leaning against milk crates?

Has your geography not invented "wind" yet?
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Re: The Greg's Grid Tie Solar Project

Post by johu »

MattsAwesomeStuff wrote: Fri Jun 02, 2023 11:47 am Has your geography not invented "wind" yet?
Been there :) viewtopic.php?p=55950#p55950
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

MattsAwesomeStuff wrote: Fri Jun 02, 2023 11:47 am You've had the panels up there for years, just leaning against milk crates?

Has your geography not invented "wind" yet?
yeah I was kinda laughing at myself when I said that, since years literally means 2 and I did take them off the patio for that massive wind storm we had, so it's years, just not consecutive, lol
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

Are Harbor Freight 100 watt solar panels really that good?






and here's a 1 year later review


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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

... and if they are, is now the time to get them?

HF 100 Watt Panel Sale.jpg
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Re: The Greg's Grid Tie Solar Project

Post by alexbeatle »

Any chance you've looked at how to limit the PV production based on your house consumption needs?
I've spoken to PG&E (my grid company) and they said it's not allowed to send energy back to them without permit-ing system and signing up for their NET metering program. I've read somewhere that some folks received letters of warning from PG&E, that they will get disconnected from the grid if they continue sending back energy.

I have now successfully installed 200w panel with a 1000w inverter which produce max. 155w. My house consumes under 250w in idle (green house grow lights, ambient lights, internet, other small things, etc.). But then once in a while a fridge kicks in, washing machine, dryer, etc. Needless to say, I'm in the market to get more panels. However with that brings a question of how to not send the excess energy back to grid at all. As I understood, these inverters do not natively support current limiting function.
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

alexbeatle wrote: Fri Jun 02, 2023 6:48 pm Any chance you've looked at how to limit the PV production based on your house consumption needs?
I've spoken to PG&E (my grid company) and they said it's not allowed to send energy back to them without permit-ing system and signing up for their NET metering program. I've read somewhere that some folks received letters of warning from PG&E, that they will get disconnected from the grid if they continue sending back energy.

I have now successfully installed 200w panel with a 1000w inverter which produce max. 155w. My house consumes under 250w in idle (green house grow lights, ambient lights, internet, other small things, etc.). But then once in a while a fridge kicks in, washing machine, dryer, etc. Needless to say, I'm in the market to get more panels. However with that brings a question of how to not send the excess energy back to grid at all. As I understood, these inverters do not natively support current limiting function.
Excellent question and yes. These cheap Grid Tie inverters do not have a current limiting function, however that does not mean none of the Grid Tie inverters don't have it. My other inverter which I was going to bring up later (might as well do it now) does have this feature.

Wow they really went up in price since I purchased mine.

Inverter with limiter.jpg
51ZcxVXp1vL._AC_SL1000_.jpg
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61vCbStqu2L._AC_SL1000_.jpg
71sTDTSB7yL._AC_SL1500_.jpg
619d6PFFH6L._AC_SL1000_.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

alexbeatle wrote: Fri Jun 02, 2023 6:48 pm Any chance you've looked at how to limit the PV production based on your house consumption needs?
I've spoken to PG&E (my grid company) and they said it's not allowed to send energy back to them without permit-ing system and signing up for their NET metering program. I've read somewhere that some folks received letters of warning from PG&E, that they will get disconnected from the grid if they continue sending back energy.

I have now successfully installed 200w panel with a 1000w inverter which produce max. 155w. My house consumes under 250w in idle (green house grow lights, ambient lights, internet, other small things, etc.). But then once in a while a fridge kicks in, washing machine, dryer, etc. Needless to say, I'm in the market to get more panels. However with that brings a question of how to not send the excess energy back to grid at all. As I understood, these inverters do not natively support current limiting function.

this is a much more efficient inverter as well, it only has 10% losses, I am not using the current limiting function but I might set it up, I also bought the remote Wifi dongle for it but I could not get it to work.

IMG_3010.JPG
IMG_3008.JPG
IMG_2992.JPG
IMG_2998.JPG
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

not sure this is the right video but I tried to find one of the first / earlier ones on these types of Sun inverters with current limiters. Current limiter prevents this device from sending electricity back to your electrical company, some cities don't allow you to send power back to their power plant.


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Re: The Greg's Grid Tie Solar Project

Post by Scrappyjoe »

Our city power utility advises us to set our inverters to trickle charge a tiny amount from the grid - in the order of 25-50 watts for an 5kw inverter - until they get round to installing current blocking devices. This trickle charge apparently stops current going back. Then again, our city also publishes an approved list of inverters, which all have this functionality. Not sure if your one would have such a function.
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

Should you fuse your solar panels?

Should you fuse solar panels in series? If so how?

Should you fuse solar panels in parallel? If so how?


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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

It's a good idea to fuse your solar panels, I get these inline weather proof fuses off of AMAZON

Fuse.jpg
61eNgsst3AL._AC_SL1500_.jpg
Fuse apart.jpg

In a pure series setup like the one below you only need one fuse:
51aD3Ryr5TL._AC_SL1000_.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

so lets pop some fuses in...


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Re: The Greg's Grid Tie Solar Project

Post by alexbeatle »

Gregski wrote: Fri Jun 02, 2023 8:13 pm not sure this is the right video but I tried to find one of the first / earlier ones on these types of Sun inverters with current limiters. Current limiter prevents this device from sending electricity back to your electrical company, some cities don't allow you to send power back to their power plant.
Thank you.
I actually have looked at these before with appetite, but the price tag isn't friendly.
I snagged a good deal on a couple of older solar panels and a dumb inverter. I'm going to play with these for now, before upgrading to a better inverter with the current limit function.
I'm gonna build a dynamic energy "waster" in the meantime out of parts I have laying around.
Gregski wrote: Sun Jun 04, 2023 2:10 pm so lets pop some fuses in...
Literally just bought these realizing the potential hazards of the (especially used) PVs!
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Re: The Greg's Grid Tie Solar Project

Post by arber333 »

Gregski wrote: Sun Jun 04, 2023 2:10 pm so lets pop some fuses in...
I put those in the middle of my panel pack so they could open the circuit in case anything happens. I use 20A fuses since one panel rating is 13A.
For full pack fuse in the house i use 25A automatic fuse:

https://www.aliexpress.com/item/4000529 ... 6WIpWfdk1E
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

alexbeatle wrote: Mon Jun 05, 2023 6:28 am Literally just bought these realizing the potential hazards of the (especially used) PVs!
Which amp rating did you end up getting, mine are 15 amps and now i am second guessing myself weather I should have opted for the 10 amp (I basically ran what I had from a prior implementation)
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

Elon has the Giga Watt Factory, I give you the Grega Watt Patio

this is what I call Solar South, ten 100 watt (mostly Rich Solar) solar panels, facing ... [ wait for it ] South ! at some unspecified angle, which is fully adjustable by sliding the supporting milk crates back and forth (perhaps we shall measure this angle some day)

IMG_3245.JPG

IMG_3243.JPG

Solar South Wiring.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

Great now what?

Well now we add a cheap DC power meter to our system to measure how many watts this 1,000 watt solar net can catch. We already know that when they ( the solar panel manufacturers ) say it's a 100 watt solar panel, it is not, so what is it? lets find out

DC Power Meter.jpg
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61v7fROUBcL._AC_SL1500_.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

so let's see that beauty installed





IMG_3218.JPG
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Re: The Greg's Grid Tie Solar Project

Post by alexbeatle »

Gregski wrote: Mon Jun 05, 2023 1:42 pm Which amp rating did you end up getting, mine are 15 amps and now i am second guessing myself weather I should have opted for the 10 amp (I basically ran what I had from a prior implementation)
I went with 10A, but it is still on order, cannot tell if it will cause frequent blows or not. And I went with a smaller value because the panels are used. I may even go smaller if 10A doesn't cause issues.

To be more technical, per NFPA70, sometimes you need to add fuses, other times they will not make any difference. You can check the NFPA70 section 690 for all of the solar stuff. Free Access to NFPAs (just need to create an account) - https://link.nfpa.org/free-access/publications/70/2023.
There you can also find the California Electrical Code, which is mostly same as National, but sometimes there're differences. Not for this case though.

A snapshot of the rule about the overcurrent protection:
image.png
I will be connecting 3 of the Canadian Solar CS6P-255PX panels in parallel. According to: http://www.solardesigntool.com/componen ... sheet.html
Isc (short circuit current) is 9A and the Series Fuse Rating is 15A. I'm assuming it's actually a max Series Fuse Rating. So smaller value can be used.

So based on my setup, the condition 690.9(A)(1)(2) won't be met and hence I need to have fuses on all branches. That is because 9A*3 = 27A, which is greater than 15A fuse rating of each PV.

If it was a brand new PV, I'd just use a 15A fuse.
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

so with the DC meter installed I am now able to see how my 1000 watt system is doing, and it aint doing as good as I thought, so I go troubleshooting and find a few issues

so first, just because you have a brand new cable doesn't mean it is good, can you spot what is wrong with this 5' extension cable?

IMG_3253.JPG
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5 foot extension cable.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

sending power back to the city's municipal utility district like a Boss ? (or is it like a fool?)

SMUD Sending Power Back.jpg
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Re: The Greg's Grid Tie Solar Project

Post by Gregski »

and here is what a day looks like, I am capturing more solar power than what I use from 10am until 6pm

SMUD Sending Power Back 2.jpg
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