Hi all,

Below are some PV specs for the Sunsynk 8kW inverter :

I would like to put two strings of 545W JA Solar modules in parallel going into ONE MPPT.  The PV modules have the following specs :
Isc : 13.93A
Imp : 13..04A

So if we have two strings in parallel, then we have :
Isc : 27.86A
Imp: 26.04A

Question 1 : Is there any danger is exceeding the PV input current?  Do the MPPTs limit themselves to 22A.

Question 2 :  If there is no danger to question 1 AND  I don't exceed the maximum input voltage of the MPPT, is there any limit to how many panels in series per string?  I've calculated that the max is 9 panels in series per string.  So could I theoretically put 2 strings of 9 panels in parallel, going into one MPPT?

Thank you,
Ryan 

I have a 8KW Deye unit, I have a theoretical max of almost 24A on my parallel string (460W panels) and my inverter clips the current above 20A. I have seen it clip the current on nice sunny days (but I only have 4S2P). So you should be ok over-panelling on current if you do not mind the Watts that you paid for that will not be used.

Personally I would rather install 640W panels and put 8 in series for a total of 5120W per MPPT. Assuming that you have the roof space with the exact same orientation and no shading

The MPPTs can also only handle a certain amounts of watts, 10400W if I am not mistaken so anything over 5200W per MPPT will be wasted power. The MPPT can only handle a certain amounts of watts and will heat up accordingly so they normally thermally throttle them with the software or they will give an error and shut down. The MPPTs work independently of each other so you need to stick to a number around 5200W per MPPT

You are not going to get the benefit of 18 Panels on one MPPT. Rather split them over the 2x MPPTs or get smaller panels or do not put parallel panels.

 

I have had this happen 2 days in a row on a 8kW Sunsynk. I have 7.2kWp installed. I assume the inverter is clipping at 9000w.

 

Why would you want them all on one MPPT? Not saying you shouldn't, not saying can't  I just can't work out why you would, when you've got two MPPTs available to you on the inverter (I think).

Jay

I just found this. Good description of PVs in parallel, use of multiple MPPTs etc. Enjoy.

https://www.solarpowerworldonline.com/2014/02/dual-mppt-defined-understanding-mppt/MPPT provides the installer,all using a single inverter.

BTW there are lots of other good articles on this site.

Jay

On 2022/12/14 at 1:20 PM, farmer barnes said:

I just found this. Good description of PVs in parallel, use of multiple MPPTs etc. Enjoy.

https://www.solarpowerworldonline.com/2014/02/dual-mppt-defined-understanding-mppt/MPPT provides the installer,all using a single inverter.

BTW there are lots of other good articles on this site.

Jay

My browser indicates this link no longer exists. 

1 hour ago, Scorp007 said:

My browser indicates this link no longer exists. 

https://www.solarpowerworldonline.com/2014/02/dual-mppt-defined-understanding-mppt/