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Hi,

My Solar Edge system uses their optimisers type P404. It is described as 60/72 cell module compatible. I’m using QCell panels and seem to have an issue with one particular panel - which is a 315 watt version. The panel data sheet says it’s 6 x 20 half cells. Any ideas as to whether it’s compatible or not? It sort of works, but the output from this panel only seems to be about 60% of other panels which have similar illumination. I’ve got my supplier scratching their head - but wondered if anyone else has an opinion at all.

Cheers- Rob

Not sure whether this helps at all, but:

Have you tried the "obvious" checks, making sure all the connectors are clean and properly fitted?
Have you tried that panel on a different optimiser and the optimser on a different panel?

What is the spec of the other panels ?

I'm not 100% sure about Solar Edge, but if they work like TIGOs, if you have a higher power panel which naturally runs at a higher current, in a string of lower current panels, the higher current panel will have to limit its current to match the lower current panels. It will run at a higher voltage which partially compensates but won't be able to run at the max power point of that panel.

nowty wrote: ↑Fri Sep 30, 2022 2:48 pm What is the spec of the other panels ?

I'm not 100% sure about Solar Edge, but if they work like TIGOs, if you have a higher power panel which naturally runs at a higher current, in a string of lower current panels, the higher current panel will have to limit its current to match the lower current panels. It will run at a higher voltage which partially compensates but won't be able to run at the max power point of that panel.

Am getting that checked - but as they are on the roof it’s a bit of an issue. The string is of 16 in total - all using P404 optimisers with 13 being 300 watt, 6 x 10 cell array. I had 3 added to the 13 and am getting good results from 2 of them and 1 being poor. The poor one has turned out to be a 315 watt panel - hence the question.

Countrypaul wrote: ↑Fri Sep 30, 2022 2:42 pm Not sure whether this helps at all, but:

Have you tried the "obvious" checks, making sure all the connectors are clean and properly fitted?
Have you tried that panel on a different optimiser and the optimser on a different panel?

Yes all good. I’ve swapped the optimiser, but panel swapping ain’t so easy!

Lincs Robert wrote: ↑Fri Sep 30, 2022 2:57 pm

nowty wrote: ↑Fri Sep 30, 2022 2:48 pm What is the spec of the other panels ?

I'm not 100% sure about Solar Edge, but if they work like TIGOs, if you have a higher power panel which naturally runs at a higher current, in a string of lower current panels, the higher current panel will have to limit its current to match the lower current panels. It will run at a higher voltage which partially compensates but won't be able to run at the max power point of that panel.

Am getting that checked - but as they are on the roof it’s a bit of an issue. The string is of 16 in total - all using P404 optimisers with 13 being 300 watt, 6 x 10 cell array. I had 3 added to the 13 and am getting good results from 2 of them and 1 being poor. The poor one has turned out to be a 315 watt panel - hence the question.

Are the 3 you have added all the same spec ?

If they are, have you tried completely re-starting the system.

AC OFF
DC OFF
Wait a minute
DC On
AC ON

I did have a peculiar problem with replacing a TIGO of mine last year which left me completely flummoxed, but the following day it all worked fine.

I've just scanned datasheets for both panels, they look so similar, I cannot imagine a compatibility problem.

300W 10 x 6
https://www.q-cells.co.uk/uploads/tx_ab ... v01_EN.pdf

315W 20 x 6
https://www.pluginsolar.co.uk/wp-conten ... heet-3.pdf

nowty wrote: ↑Fri Sep 30, 2022 3:15 pm

Lincs Robert wrote: ↑Fri Sep 30, 2022 2:57 pm

nowty wrote: ↑Fri Sep 30, 2022 2:48 pm What is the spec of the other panels ?

I'm not 100% sure about Solar Edge, but if they work like TIGOs, if you have a higher power panel which naturally runs at a higher current, in a string of lower current panels, the higher current panel will have to limit its current to match the lower current panels. It will run at a higher voltage which partially compensates but won't be able to run at the max power point of that panel.

Am getting that checked - but as they are on the roof it’s a bit of an issue. The string is of 16 in total - all using P404 optimisers with 13 being 300 watt, 6 x 10 cell array. I had 3 added to the 13 and am getting good results from 2 of them and 1 being poor. The poor one has turned out to be a 315 watt panel - hence the question.

Are the 3 you have added all the same spec ?

If they are, have you tried completely re-starting the system.

AC OFF
DC OFF
Wait a minute
DC On
AC ON

I did have a peculiar problem with replacing a TIGO of mine last year which left me completely flummoxed, but the following day it all worked fine.

There’s some doubt that the 3 new panels are the same spec as each other. I know the 315 is a 6 x 20 half cell construction, but the other 2 are on the roof & not easily accessible. They have bar-codes on the front which I’ve got an enquiry into QCells about, so I’m hoping they can clarify. Thing is that the 315 has always underperformed so I moved it to be next to a couple of the 300s, it’s performance is only 60% of theirs.

My supplier couldn’t source additional 300 watt panels at the time, Dec 21, so I think provided the 315 and a couple of 305s. It seems there are a couple of versions of the 305s, a 6 x 10 version and 6 x 20 version. Curiouser & curiouser!

My gut feeling is that I have a couple of compatible 305s and the incompatible 315 - which is giving the reduced performance. My supplier doesn’t have exact records of what was provided and advises that he’s NEVER had a qcell panel failure - which is fair enough.

I’ll get to the bottom of this - but can see an exploratory trip onto the roof being needed unfortunately.

nowty wrote: ↑Fri Sep 30, 2022 3:23 pm I've just scanned datasheets for both panels, they look so similar, I cannot imagine a compatibility problem.

300W 10 x 6
https://www.q-cells.co.uk/uploads/tx_ab ... v01_EN.pdf

315W 20 x 6
https://www.pluginsolar.co.uk/wp-conten ... heet-3.pdf

If you look in the detail, the 315 says 6 x 20 (120), but the 305 says 6 x 10 (60). The P404 optimiser is “only” 60 & 72 compatible- so I suspect that the 120 config of the 315 is the issue. There’s also a 120 version of the 305, these versions are marketed as DUO.

It’s raining today, sunny tomorrow hopefully . Luckily my mate is coming round with his ladder

On further digging, SE do a range of optimisers for 2 x 60 etc, the P650 range. They aren’t compatible with the P404s that I have