Sol-Ark 15's, low PV output - what to investigate?

[Wzrdmatt]

Hi Everyone,

Long time lurker, and first time poster. I had a solar setup professionally installed and I fear there are some problems. Not getting the best support from the company, so I'm looking for some help here to see if I can identify what's wrong.

We're located in Northern California, with 28KW of solar facing south. No trees, nothing blocking the arrays... The setup is connected to two sol-ark 15k inverters. Each inverter has half the panels attached to it.

It's been cloudy today in California, but had some great periods of strong sunshine for the first part of the day. The generation of these units is all over the map, mostly bouncing around <500watts generated, and sometimes hitting as low as 9w in a given period (no rain, just some clouds). I'm no expert, but I'd think a 28kw setup this should be producing much more. At one point today something happened (no change in sun) and one of the units went crazy generating significant PV power (10kw)...and then they went back to <500watts, at times hitting as low as 20 watts. It was very weird, but shows there is potential for generation here...




I'm pretty handy with electrical, but I have no clue where to start with these Sol-Arks. Any advice on where to start looking for problems to fix?

PS. I did notice one of the inverters / strings is potentially wired incorrectly (see photo). Inverter 2, String 1 seems to have one positive leg on the wrong terminal PV3+ (see photo); or maybe all strings are wired wrong here.... Inverter 2 seems to have the most volatility, going from 2kw to 0 throughout the day.


PSS. I have Homegrid batteries installed. The Homegrid are installed 1 stack (19.2 per Sol-Ark) to each inverter; the inverters are setup as independent (not parallel). Not sure why they did this, but will likely need to change this to a parallel setup in the future.

 

[Danke]

 

[Nobodybusiness]

Hi Everyone,

Long time lurker, and first time poster. I had a solar setup professionally installed and I fear there are some problems. Not getting the best support from the company, so I'm looking for some help here to see if I can identify what's wrong.

We're located in Northern California, with 28KW of solar facing south. No trees, nothing blocking the arrays... The setup is connected to two sol-ark 15k inverters. Each inverter has half the panels attached to it.

It's been cloudy today in California, but had some great periods of strong sunshine for the first part of the day. The generation of these units is all over the map, mostly bouncing around <500watts generated, and sometimes hitting as low as 9w in a given period (no rain, just some clouds). I'm no expert, but I'd think a 28kw setup this should be producing much more. At one point today something happened (no change in sun) and one of the units went crazy generating significant PV power (10kw)...and then they went back to <500watts, at times hitting as low as 20 watts. It was very weird, but shows there is potential for generation here...

View attachment 190583
View attachment 190584

I'm pretty handy with electrical, but I have no clue where to start with these Sol-Arks. Any advice on where to start looking for problems to fix?

PS. I did notice one of the inverters / strings is potentially wired incorrectly (see photo). Inverter 2, String 1 seems to have one positive leg on the wrong terminal PV3+ (see photo); or maybe all strings are wired wrong here.... Inverter 2 seems to have the most volatility, going from 2kw to 0 throughout the day.
View attachment 190585

PSS. I have Homegrid batteries installed. The Homegrid are installed 1 stack (19.2 per Sol-Ark) to each inverter; the inverters are setup as independent (not parallel). Not sure why they did this, but will likely need to change this to a parallel setup in the future.

Do you have a solar combiner at the array?
Do you have any form of disconnect at the array or between the array and the inverter.

You shouldn’t have 1 positive wire on PV1+ and 2 negative wire on PV1 -.
You are also missing a negative from PV3-.

Disconnect the array and trace the wires from the inverter to each string if you can.

I can see they are numbered but can’t read them.

Be very careful as those will have 300+ VDC on each string.


You have to pair them up with where they come from.

Also just check and make sure the PV switch is in the on position on the side of the inverter.

What does the other inverter look like?


Each MPPT channel has the ability to connect 2 strings for a total of 6 strings.

If you have a combiner at the array the it will only have 1 connections per MPPT channel.

You will not be able to connect 28kw of panels to one inverter only unless it is way over paneled.

 

[Oldphile]

The wire may be reversed as it connects on the roof. My installer did that. I have a red wire on the negative MPPT terminal.

 

[DVD]

I did my own install and had a problem. My solution was to disconnect each array by separating the series connection at the panels, check for no shock hazard, then using an ohmmeter figuring out what was connected to where.

 

[Tulex]

The wire may be reversed as it connects on the roof. My installer did that. I have a red wire on the negative MPPT terminal.

Between the OP's picture and your statement, I'm glad I did my own.

 

[Tulex]

If this installer thought it was OK to connect the wires like he did, and you have 4 strings going to each inverter, there's nothing saying he even has pairs going to each inverter. You really need to trace the wires back to the panels. If you can't physically verify pairs, you may have to disconnect them on both ends to find pairs. Lots of ways to do that. Get a line tester, or run some juice through a pair and find the juice on the other end. Just make sure they are all disconnected and not touching. Or disconnect all but one pair at the panels and find the pair at the inverters.

In the summer, I had one bank set up, 2 strings in it for a total of 6370 watts. I had one string on PV1 and one on PV 2 so that I could see how each string was doing. On sunny days, I was getting 6000+ watts.