Advice on my installed solar system - missing optimisers?

TLDR - I have a system that is supposed to have optimisers fitted, but I am not sure they have been fitted.

The detail:
Back in March I had a solar system installed. It was installed on two outbuildings, and as one of the outbuildings has a tree near it which can cause some shading, I was advised to have optimisers fitted to 7 of the 9 panels on the array. The second building (5 panels) has no such shading, so didn't need any. Each outbuilding has its own subboard, and each array has its own inverter wired into the subboard. The generated power then comes back to the main fuseboard where we have a battery inverter and batteries fitted.

All works well, and we are getting plenty of power generated, but I started noticing an interesting thing on the app's monitor - the power output would build slowly up until around midday, and then suddenly bounce up massively.





...so I looked, and the leap in output coincided with the shadow of the tree coming off the last of the panels.

Here's a photo (actually from a different day, but you get the idea) of the panels with 4 partly shaded, and the inverter showing an output of 60W



...which confused me, as I understood the idea of the inverters is so the panels act as if wired in parallel, so that panels that are not generating are skipped but the other panels can generate.

At the same time of the day, the other unshaded array of 5 panels was putting out 1270W.

So I went up onto the roof and had a look underneath. Each panel was connected in series, with no evidence of an optimiser being fitted.



...this means of connection was the same for all 9 panels, and for the other array of 5.

I have contacted the installer on several occasions with this same photographic information, and have been brushed off by their (very friendly and as helpful as they can be) reception staff, them basically passing on messages from the more senior people that "the system is working well" and "it could have been cloud cover causing the drop". I was also told it might be that I had panels installed with built in optimisers - though I think this is the reception staff trying to be helpful rather than any actual knowledge.

All panels are identical - model number is JA Solar JAM60S21-365/MR - so I don't for a moment believe they have integrated optimisers. The information pack states that they would be fitting Tigo optimisers.

Can someone please advise - am I correct in thinking that the optimisers have not been installed? I would like to have a definitive answer before I take it up more officially with the installers/trading standards.

Thanks folks!

Difficult to say from pic. There does appear to be something there as panels normally just have a plug and socket where yours has a plug and socket but a free hanging oblong box.

To be fair, panels have bypass diodes built in to deal with this but there does need to be a minimum voltage needed. The inverter carries out a periodic Power point tracking calculation and it looks like the jump is the inverter doing a re-calculation and moving to a different volts range to get more power.

The inverter looks like a Solis, what is the model No ?

plugsandsparks said:

Difficult to say from pic. There does appear to be something there as panels normally just have a plug and socket where yours has a plug and socket but a free hanging oblong box.

To be fair, panels have bypass diodes built in to deal with this but there does need to be a minimum voltage needed. The inverter carries out a periodic Power point tracking calculation and it looks like the jump is the inverter doing a re-calculation and moving to a different volts range to get more power.

The inverter looks like a Solis, what is the model No ?

Click to expand...

Thanks for the reply.

Sorry, the angle of the photo wasn't great - the right hand block that looks a bit like a box is the coiled cable viewed end on...



Solis model is S6-GR1P4K

OK, there is no optimiser on those panels. I will look at the inverter tonight when i get back to see what i would expect to see with your set up.

plugsandsparks said:

OK, there is no optimiser on those panels. I will look at the inverter tonight when i get back to see what i would expect to see with your set up.

Click to expand...

Many thanks.

To be clear, the graph I posted is a combination of the two arrays. When the electrician set things up, he asked if we wanted the monitoring to be per inverter, or summed as one feed, saying that the one feed was what most people chose, so we followed that advice - he did explain that the amount showing as generated would be minus any consumption within the outbuilding. I assume therefore the CT clamp that monitors output was fitted to the main cable supplying power to the outbuildings (and sending it back from the panels).

So where the graph is showing a growing output up to 12ish, that is mostly from the second array - which at the point I took the photos was producing 1270W, with the 9 panel array just giving 60W.

As a side issue, what I have realised is that this CT clamp does not seem able to distinguish between generation and consumption, treating anything on that cable as generation. So when (say) the electric shower in the outbuilding is used, this shows as generation, not consumption.



I must admit I thought that the monitor would be able to distinguish between consumption and generation, but maybe I am misunderstanding. I wish I'd asked for each inverter to be monitored separately now, as that would have made it a lot more obvious what was going on.

Again, I have sought an explanation from the installer, and not been given anything useful

Assuming the other inverter is also Solis, what would be helpful is a photo showing clearly the underside of the inverters, i need to see how many DC cables (black) are connected and to which ports. I need to see the Comms port to see if any wifi or wired comms have been installed. I am totally confused about the Cts and your graph as if your load is showing as a positive in production the graph is just nonsense and i would not rely on it.
What App are you using to give this graph and what make model is the battery system and what App do you have with that.

the out of box Solis App can show you each inverter BUT the App is laggy and it will not show realtime unless you keep proding it.

Also are both building the same orientation and panel angle, i.e. are they both comparable as if 5 panels can produce 1200W and 9 is only giving 60W at the same time, given the above then investigation is warranted, regardless of a couple of panels having shading.

plugsandsparks said:

Assuming the other inverter is also Solis, what would be helpful is a photo showing clearly the underside of the inverters, i need to see how many DC cables (black) are connected and to which ports. I need to see the Comms port to see if any wifi or wired comms have been installed. I am totally confused about the Cts and your graph as if your load is showing as a positive in production the graph is just nonsense and i would not rely on it.
What App are you using to give this graph and what make model is the battery system and what App do you have with that.

the out of box Solis App can show you each inverter BUT the App is laggy and it will not show realtime unless you keep proding it.

Also are both building the same orientation and panel angle, i.e. are they both comparable as if 5 panels can produce 1200W and 9 is only giving 60W at the same time, given the above then investigation is warranted, regardless of a couple of panels having shading.

Click to expand...

Both buildings are pretty much identical orientation, and roof angle is the same as well.

9 panel inverter


The other array's inverter is a Solis as well, though a S6-GR1P2.5K-M - sized for the smaller array I assume.

5 panel inverter



Battery system is a Sofar ME3000SP hooked up to two Pylontech US3000C batteries.

As I understand it, they have not added any comms to the two Solis inverters, but just the Sofar battery inverter. I am guessing there is a CT clamp on the 10mm armoured cable that takes power out to the outbuildings, so it is measuring the output based on what is coming back from the outbuildings - but also interpreting consumption as generation. So I think it is the Sofar that is sending the data to the monitoring app.

The monitoring app is Solarman, which lags by about 5-10 minutes - one of the reasons I have done my tests on fully sunny days, where off and on cloud cover can't confuse the results.

As I say, I think they have done it this way so we just get a single control panel showing what should be total generation, but if I had been told of the negatives of this approach, I certainly wouldn't have chosen this way.

In terms of CT location it may be that the layout of your electrical circuits means accurate readings are not straight forward. Ideally there should be one set of CTs measuring combined solar production only and one set of CTs measuring total load or possibly a set of CTs on your grid connection. If you are producing from the outbuildings and also creating a load at the outbuildings and the CTs are measuring at the house, this will give false readings. Hope that makes sense.

The Solis Inverters offer a cheap simple comms using Wifi devices that plug into the Comms port.
Part No: SOL-DLS-W3

They are around £30 each and you need two, one for each inverter. You do need a wifi signal from your router at the outbuildings or they will not work. If you get these you can download the App, its free and configure them to your situation. That way you will get proper actual production generated and it also outputs each PV string Volts and Current , so a good way for fault finding and getting the optimum out of the array.
Both of your inverters are dual string, i.e. you can split the panels across both inputs. There are plus' and minus' when you have a low number of panels but for the 9 panel array you may wish to split them 5/4 and use both inputs. This will allow the inverter to have different settings for the panels in shade and the panels not in shade which may help. To achieve this you need to run two more black cables to the middle of the panels and split the array into two.

I would get proper monitoring on there first before looking at splitting the array.

Thanks - that's all a great help.

Frustrating that the installer didn't offer these suggestions - and I still need to address the fact that they have charged me for optimisers that have not been fitted. Of course, the optimisers are not available anywhere at the moment due to supply issues. Alternatively, if they had suggested splitting the array it might well work nearly as well as if optimisers were fitted, which would have saved me money.

Those logging sticks look to be a bit pricier - certainly from where I can get them from - cheapest I can see is £50 each plus shipping. I'll see whether my installer can at least do something to get me those at a better price.

I think you are right about the false readings - the guy who did the installation did warn me that the measurement would be less any power consumed in the outbuilding, but I hadn't realised it would take consumption as generation - I assumed the CT clamp would ignore any flow going the "wrong way".

Once again, I am very thankful for your assistance.

Yes, get your installer to supply i pay just less than £30 but they are added to other stuff so dont pay carriage.

The panels you have are quite sophisticated and can handle shade in terms of not killing all production but the inverter is trying to get the best out of all the panels combined and sometimes its better to split.

For the cost of a couple of cables and connectors its worth a try, if it does not improve it you can always revert.

But get monitoring on first

Well, lo and behold. I called the installers up and insisted (politely) on speaking to someone in authority. Explained I had asked for second opinions on the lack of optimisers.

Suddenly they agreed that the installation was missing them - and even more miraculously, they discovered they had an early delivery of optimisers, and someone is coming to fit them tomorrow.

Next, to try and get the dongles....

richardh said:

Well, lo and behold. I called the installers up and insisted (politely) on speaking to someone in authority. Explained I had asked for second opinions on the lack of optimisers.

Suddenly they agreed that the installation was missing them - and even more miraculously, they discovered they had an early delivery of optimisers, and someone is coming to fit them tomorrow.

Next, to try and get the dongles....

Click to expand...

Lol, wifi sticks are also low stock / no stock. My inverter has just been pushed back from early Sept to Mid Nov, its a jungle out there......