Hi there

 

I've read through several topics, but can't find one with my problem. I'm new to solar and need advice. I originally had a 8.5kva Fivestar inverter with 6 x 454w panels. Everything ran great, getting at peak 3kw of power. I added 3 more panels for morning and 3 panels for afternoon sun. The installer connected everything parallel and my wattage dropped. Found out the panels not getting sun affects the ones getting sun. The inverter could only take one string, so I replaced it with 2 x 5kva Deye inverters. Here is where the frustration starts...Currently I have 3 strings. 1 x 6 panels that is my main panel as it's at an angle to get sun basically the whole day. The 2nd string is 3 panels for the morning and 3rd string is for afternoon sun with 3 panels. All connected in series. The 6 panel string produces at best 1.5kw now and the other 2 strings at most 10-200w each. The current connections are primary inverter has the 2 x 3 panel strings and the slave has the 1x6 panel string...There was an issue on the db board that the installer had to sort out and he made a temp connection yesterday, disconnecting the one 3 panel string from the master and running it straight to the slave together with the 6 panel string. This morning it was very cloudy and the strings on the slave produced 2.2kw together. The afternoon one also produced roughly 100-400w...The installer fixed the issue on the db board and moved everything back and now I'm back to producing almost nothing. He left for the day, so I need advise from someone please?? I have 3 batteries connected in parallel.  The input voltage of the 3 panel strings are roughly 129v each. If there is more info needed I will try and give..In future I plan to add 6 more panels in series together where the existing 6 panels are. Then the idea was to connect the strings as follows: 1 x 3 panel + 1 x 6 panel per inverter, spreading the power coming in. Would it be advisable to connect the 2 x 3 panels in series making it one string? How will the sun shining affect it...currently the afternoon panels generate in the morning as well...not sure why

Edited December 20, 20241 yr by termdj
Typo

Whats the start up voltage of the mppt on deye inverter?

15 minutes ago, AndrewJdc said:

Whats the start up voltage of the mppt on deye inverter?

If I am not mistaken 120V or 125V

3 hours ago, termdj said:

The input voltage of the 3 panel strings are roughly 129v each

This is barely enough to get the MPPT started - if at all. So I am not surprised if you are not getting any production out of these strings

3 hours ago, termdj said:

Would it be advisable to connect the 2 x 3 panels in series making it one string?

As they are facing different directions, this will not help you much. Either put all panels facing the same direction or add more panels to each string to make sure that you have sufficient voltage on each string to get the MPPT started

Edited December 20, 20241 yr by wolfandy

Andrewjdc...starting voltage is 125v...the highest I have seen the panels go up to is 134v

@wolfandy the 2 x 3 strings face different directions...one morning, one afternoon...how will connecting them in series work as they are very close together by creating 1 string of 6? Will it be that they negatively affect each other as one gets sun in the morning while the other one doesn't and vice versa in the afternoon? Like take half the wattage away type of scenario?  Not sure if I explained it okay...I know when I connected the strings together in parallel it negatively affected the wattage, due to the sun not shining on all the panels at the same time

3 hours ago, termdj said:

@wolfandy ...I know when I connected the strings together in parallel it negatively affected the wattage, due to the sun not shining on all the panels at the same time

If you had a low voltage start inverter then this would work very well and far better than having the 2 different directions connect 6 in series. Your problem is the Deye needs a high voltage of over 125V with all panels facing the same direction. If you can add 1 panel to each direction you can use each set of 4 into it's own MPPT and it will work well. 

The startup Voltage is 150V.

And 125V is actually the shutdown Voltage.

As above, you need at least 4 panels in series per string, and if you can feed each to its own PV input, that'll be best.

@GreenFields I checked the manual.and the startup is 125v and the mppt voltage range is 150-425v. I will talk to the installer for more panels...thanks

I'm going on memory from datasheets I've seen in the past, such in the link below. If the specs have changed, or if there are different versions, I'd defer to your manual. Either way, you need strings longer than 3.  

https://www.solarwaysuppliers.co.za/wp-content/uploads/2014/01/5kW-Deye-Sunsynk-Hybrid-PV-Inverter-Datasheet.pdf

Thanks...can I connect them.in series as they are close enough and make 1 string of 6, but how will it be affected when only half the panels.get sun in the morning and then the other half onlymin the afternoon?

39 minutes ago, termdj said:

Thanks...can I connect them.in series as they are close enough and make 1 string of 6, but how will it be affected when only half the panels.get sun in the morning and then the other half onlymin the afternoon?

Rather not. Usually the shaded part of the string would lower the output on the entire series string.

If you want to avoid buying new panels for now, you could try to transfer two panels from the North-string, one to each of the East and West strings. 

Thanks.  I will take it up with the installer to see what will be the most cost effective...

Edited December 21, 20241 yr by termdj

The Sunsynk and Deye has a startup voltage of 150v. Not less than 4 panels/ string 5 panels/string would be more efficient during cloudy weather. You have 2 x Mppt's/ inverter so connect each orentation(E N W) per Mppt and from there you can add panels to each string. The golden rule do not connect panels in series from different orientations. 

Thanks...will move panels around to make it minimum 4 per string