Looking for wiring tips

[LeeLewis]

I'm sorry, I'm new to solar terminology. Having to learn because the installer left us hanging with this system and no support.
The terminology seems to vary in different locations because many youtube videos, articles, documents say either method of connecting multiple panels together means a 'string'. I've also seem some mention that only series is considered a string so, hard to learn for a newbie but trying.

I think I'll end up having to go series otherwise, I'll have to build something (as mentioned) or buy much more costly combiners.
That said, I might go with a series & parallel configuration.

Anyhow, I think the question can be closed now.

photo_2023-06-29_12-28-08.jpg
I took a picture of a label on the solar and it's the same as the tech specs showing only the AC output.

That was the DC output of the solar so really, useless information since the meters can only do that using alternating current.
I have to find a way to meter the current output.

[bcroe]

The language here is, a string of panels means they are wired in series. Bruce Roe

[SunEagle]

It's now the best time of day to test so I went out with a current meter to check the panels. On average, the panel reading was 0.15 amps (not ma).

Is that amp reading AC or DC? I think those micros allow you to parallel those panels which is not what you can do considering your desire to have each panel provide power if the others are shaded.

You will have to decide to go series if you want a DC inverter or build your own combiner box with bigger circuit breakers if you want to parallel the panes and still go DC otherwise you are stuck staying with the micros and going AC

[LeeLewis]

It's now the best time of day to test so I went out with a current meter to check the panels. On average, the panel reading was 0.15 amps (not ma).

[LeeLewis]

As I mentioned, I have shading issues so am trying to go parallel rather than series. Still wondering how you all handle higher currents such as my situation.
Typically, when it's higher amperage, installers seem to go directly to a charge controller and maybe that's always the case since I'm not finding many combiners that handle the kind of current I'm ending up with if I go parallel.

Not really sure what your comment about 101 means. I know the basics, I'm mostly asking questions about equipment and how people handle different situations.

[bcroe]

How in the world do you guys deal with non standard string sizes?
With three panels potentially putting out say around 8 amps each, I'm looking at around 24/25 amps per string but can only find 15 amp string input combiners.

If you put one, or two, or 3 panels of 8A in a series string (loop),
the current everywhere is still 8A. Only the voltage adds up.
Better go back to Circuits 101. Bruce Roe

[LeeLewis]

How in the world do you guys deal with non standard string sizes?
With three panels potentially putting out say around 8 amps each, I'm looking at around 24/25 amps per string but can only find 15 amp string input combiners.

[LeeLewis]

I initially thought each panel might be putting out under one amp so it looks like I have to seek out a new combiner since the inputs are only 15 amps.
I wondered how installers might deal with that. I guess a two panel string.

[SunEagle]

Well if the pane is rated 238W and the Vmp is around 32V then the output amps for each panel is around 7 to 8. (238W / 32V = 7.43 amps). So maybe a guess of 8 amps and 32 volts is a starting place.

[LeeLewis]

Correct and that's been the problem, not being able to get enough information and doing a lot of guessing.
I have this spec sheet on the panel but as mentioned, it includes the micro-inverter as part of the specs. Still useful, showing the panels max continuous output is 238W.
By knowing the max inputs of the micro-inverters, that could help me to get to a starting point of testing.

I could start by wiring three panels in series, connecting that string to one of the combiner inputs.
At worse, I'll blow a fuse during testing but I could monitor the output long before getting to an inverter. I've not purchased an inverter yet so my options are open.

panels-250_6_PL-US-AC-208-240-Datasheet_Rev1.pdf

[SunEagle]

Uh? I am removing the inverters to convert some of the grid tied system to a DC setup. I'm not sure where you got that. Maybe I mentioned the possibility of using non grid tied converters but I don't remember posting that, it was just a thought.

Yes, I looked at the panels closely, there's nothing on them that gives any information on output.
Since the inverters accept 18-37 up to a max of 48VDC, and the panels on average are putting out 32VDC, this tells me my panels are max 48VDC. Checking the output, I saw around 32VDC on average. I to get up there again to get some averages on amperage.

Even in the power manager, there's no actual information about current but I can use the info shown I suppose to figure that out.

Without the panel information (which it seems you have not been given) you would be guessing the open voltage that each panel can generate. That may not be an issue but you could exceed teh max DCV that the inverter can accept.

The rest (Vmp & Imp) can be gotten through testing but I now understand that changing a solar system that uses micros to a string is not always easy. I would say that the panels can generate 32VDC as close to the Vmp rating. And unless there is some type of markings showing the panel wattage it will be hard to calculate the Imp for each panel which affects the wire size and voltage drop calculation.

[LeeLewis]

In post #5 you said you will not be using microinverters and your diagrams show strings. Now you're going back to micros........? Sorry, I don't think I can help you any more. Good luck.

Uh? I am removing the inverters to convert some of the grid tied system to a DC setup. I'm not sure where you got that. Maybe I mentioned the possibility of using non grid tied converters but I don't remember posting that, it was just a thought.

Yes, I looked at the panels closely, there's nothing on them that gives any information on output.
Since the inverters accept 18-37 up to a max of 48VDC, and the panels on average are putting out 32VDC, this tells me my panels are max 48VDC.
I need to get up there again to get some averages on amperage.

Even in the power manager, there's no actual information about current but I can use the info shown I suppose to figure that out.

solar-output.png

[SunEagle]

I posted that in another comment but here it is again; https://www.amazon.com/dp/B09BTX2YQ5

I also shared the panel details in another comment but the data sheet is with the microinverter installed so they don't talk about the panel specifically other than with AC output.
I'm making guestimates based on some info about the panel which should be pretty standard and the input of the inverter to get some idea of the panel.
I'll post that info again which is from the data sheet;

Mage / Powetec Plus, 250 / 6 PL US AC.
AC output, 240V
AC Max Cont output current, 0.992A
AC Max Cont output power, 238W

The inverters are Pantheon II.
INPUT (DC) DATA P250LV-208/240
Recommended STC Module Input Power Rating 235 W – 280 W
Maximum Continuous Input Power 250 W
Maximum Input Voltage 48V
MPPT Voltage Range 18V-37V
Maximum Power Voltage Range 25V-37V
Maximum DC Short Circuit Current 15A
Maximum Input Current 10A

That is the inverter data. Not the panel DC data.

You should also have the panel data which is usually on a nameplate on the back of the panel. It should provide you with a Wattage, Imp, Vmp, Voc and short circuit amp rating. But it is possible that when you wire an individual inverter to each panel they might not give you the panel DC rating.

Without the DC data for each panel you might have to guess both the Vmp and Imp amounts to wire them the way you want to going to a single inverter.

[DanS26]

In post #5 you said you will not be using microinverters and your diagrams show strings. Now you're going back to micros........? Sorry, I don't think I can help you any more. Good luck.

[LeeLewis]

I posted that in another comment but here it is again; https://www.amazon.com/dp/B09BTX2YQ5

I also shared the panel details in another comment but the data sheet is with the microinverter installed so they don't talk about the panel specifically other than with AC output.
I'm making guestimates based on some info about the panel which should be pretty standard and the input of the inverter to get some idea of the panel.
I'll post that info again which is from the data sheet;

Mage / Powetec Plus, 250 / 6 PL US AC.
AC output, 240V
AC Max Cont output current, 0.992A
AC Max Cont output power, 238W

The inverters are Pantheon II.
INPUT (DC) DATA P250LV-208/240
Recommended STC Module Input Power Rating 235 W – 280 W
Maximum Continuous Input Power 250 W
Maximum Input Voltage 48V
MPPT Voltage Range 18V-37V
Maximum Power Voltage Range 25V-37V
Maximum DC Short Circuit Current 15A
Maximum Input Current 10A