Jump to content

Solar Array, Wiring size, Fuses and Breakers.


R3plic8
 Share

Recommended Posts

Hi.
I was hoping could maybe get some advice with sizing wiring, Fuses and Breakers, Or If my thinking is correct.

We currently have a RCT Axpert 5k 5Kva/4KW MKS, with 4 x 12V 100AH batteries in series as backup solution (We also have the same spare inverter which is not installed currently, with  parallel communication.) (https://www.comx-computers.co.za/RCT-AXPERT-5K-specifications-91891.htm)
We have got 4 x JA Solar 540W panels that we wanting to put on the system. (https://www.jasolar.com.cn/uploadfile/2021/0706/20210706053524693.pdf)

The 4 panels i plan to connect 2s as they installed east/west configuration with 15Deg slope either side(30Deg Combined) and inclined north at 10Deg.
So i have the option 1) of either putting the strings in parallel to the one installed inverter which can handle 3000W Array with a MAX Voc of 145VDC and 60A max charge. My concern would be of how much voltage drop their will be with the panels difference of 30Deg over another mppt
options 2) Would be installing the second inverter and running each string to each inverter. (We do plan to add some more panels soon)

If i went with the 2nd inverter option and the panels in series, i know i wouldn't really need any fuses/combination box as yet. and just a breaker/solar DC

If the first option wouldn't result in much loss. can we confirm my calculations for a 2s2p or more array.

The panels have a Voc of 49.60V with a lsc of 13.79A lmp of 12.97A  & The Max Fuse Rating is 25A
So if we were running 2s2P or the short Circuit current would be 27.58V and higher than the Max fuse rating.
Would Each string then require a 25A fuse as per the max fuse rating (i presume a factor of 1.56).
Then as D/C-Over current protection. the breaker for 2 combined strings of 12.97A x 2 x 1.56 is 40.4A so move up to a 45-50A DC Breaker? ( or x3 for 3 strings, x4 for 4)

And then with the array being 10m away from the inverter with Voltage drop. Cable would need to be minimum of 16mm2 for 99A max and up to 1% loss for 2 strings with 99V at 27A

If anyone can confirm my thinking and calculations would be correct. It would be a huge help. 
Thanks.
 




 


 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...