question

eoin avatar image
eoin asked

mppt rs 450|200tr one imput lower than others

I installed 36 pannels in 4 strings all same orientation and no shading. The 450|200tr has 4 imputs No.4 has allways a lower yield. In low light this is particularly noticeable. I have swopped the strings around to see if the problem was in the pannels but No.4 imput is allways down on performance. I set up the system 103 days ago with just 24 pannels so I wasn't using Imput No.4 then I completed the arrays 51 days ago and I've been hoping the problem will go away but no joy.

These are the figures for today:

No.1 8.3kwh, 2251w, 365.37v

No.2 8.2kwh, 2190w, 365.1v

No.3 8.5kwh, 2333w, 356.47v

No.4 7.2kwh, 2103w, 366.78v

mppt rs
11 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Alexandra avatar image Alexandra ♦ commented ·

And if you switch off one other string to make this one work harder?

Do you hit current limiting at all (200A)


1 Like 1 ·
eoin avatar image eoin Alexandra ♦ commented ·
I haven't hit 200amps. I will turn off a string tonight and see what happens tomorrow. Thanks.
1 Like 1 ·
eoin avatar image eoin eoin commented ·
On July 30th the battery didnt make it to fully charged so that day all power avaliable should have been used, here are the figures (imput 4 is still down):

No1 4.11kwh 886w 351.56v

No2 4kwh 869w 351.1v

No3 4.15kwh 889w 351.68

No4 3.03kwh 809w 350.73v


0 Likes 0 ·
eoin avatar image eoin Alexandra ♦ commented ·

The results are in. So this data is from today when the string for imput No.2 was disconnected, battery reached 98% charged so there was allways a draw on power.

No.1 7.39kwh,3539w,245.95v

No.2 0kwh, 0w, 6.11v

No.3 7.39kwh,2697w,350.9v

No.4 6.31kwh, 2344w,240.26v


0 Likes 0 ·
nesswill avatar image nesswill commented ·

Is string 4 at the exact same angle (might face the same way but the angle to the sun will make a difference) as the other 3 strings?

Can you post the PV Spec's/type please.

1 Like 1 ·
eoin avatar image eoin nesswill commented ·
Pannels are rec twin peek 4. 370w, vmpp 34.7v, impp 11.68a, isc 11.38a, voc 41v. 9 pannels per string.

All pannels at 70° pointed south. As I said moving the strings to different imputs on the mppt makes no difference problem stays with imput No.4


0 Likes 0 ·
nesswill avatar image nesswill eoin commented ·

Ok thank you.

Can you post a graph from VRM showing all 4 strings (i have just posted x2) over the last week please.

Something like this below please...

strings.jpg

1 Like 1 ·
strings.jpg (159.0 KiB)
eoin avatar image eoin nesswill commented ·

I only have Internet on my phone and don't own a laptop or pc so I haven't gotten vrm to work properly yet. (I'm off grid as much as I can be).

0 Likes 0 ·
eoin avatar image eoin eoin commented ·

This is the best I can do screenshot-20230810-084511.jpgscreenshot-20230810-084525.jpg

0 Likes 0 ·
screenshot-20230810-084525.jpg (262.9 KiB)
screenshot-20230810-084511.jpg (250.0 KiB)
nesswill avatar image nesswill eoin commented ·
Thank you.

I guess you have to ask yourself,

Can you live with it?

or

Do you return the unit for testing/repair/replacement? (<<< my option)

Sorry not any more I can add, good luck and please let me know what you decide and the outcome.

1 Like 1 ·
eoin avatar image eoin nesswill commented ·
Thanks a million, I've a decision to make.
1 Like 1 ·
1 Answer
eoin avatar image
eoin answered ·

The power loss is equivalent to 1.29 pannels, I've 36 pannels I think it is an acceptable loss considering the work to fix it. Maby I'm too lazy or too rich.

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·
Very funny accepted answer @Eoin :))

I agree with you, it's a bit weird, but also not enough to worry about.

Thanks for posting. I'll keep my eyes out for other similar situations.

1 Like 1 ·