Solar PV Hints, Tips & Troubleshooting

phester28

if you have 4 panels only you could diy install if access is not terrible. they are around 50 euro per panel. I dont know what a company would charge to retrofit. But it looks like your shade is causing you to loose ALOT of your potential. Of course the installer should have done a survey and spotted this so you may have some recourse to get them to resolve it on the cheap

Geeyfds53573

Seems a lot of installs require optimizers but installers just don’t bother.
Anyone have experience with the monitoring of optimizers and costs involved?
Tigo have a charged service and with Hauwei I think it’s free? Anyone I have spoken to had to retrofit them and none seem to have been aware of the possibly of monitoring them.

championc

phester28 wrote: »

Total 1.4kwh today from 2.5kwp 1.5/0.9 east west split

Those are two very small strings and must struggle to kickstart the inverter, or are they all on the one string ?

idc

Geeyfds53573 wrote: »

Seems a lot of installs require optimizers but installers just don’t bother.
Anyone have experience with the monitoring of optimizers and costs involved?.

My installer fit optimisers but at the time they could only source dual panel ones which didn't work very well so they removed those. Any of the decent installers did mention i would need optimisers for shade from neighbours and trees. Without them I achieved 68% of projected generation. Hard to know how much they would improve as parts of the day in winter entire array in shade. (No optimiser will fix that )
The installers I would run a mile from didn't even want to consider going near that roof which would of meant I'd only have a 2kWp array.


Never asked about monitoring of them. I knew that was possible but expected it would add a lot to price? One downside I do have is that my system doesn't allow independent monitoring of both strings on web interface. Sure I can on the box current kW for each string but there is no overall total of that kept as independent values. That way could better see difference in how well each string performs

phester28

yes i have solis inverter and reporting is on an aggregated basis. You have to manually extract data for each string. as for the optimizers I think you need to buy the gateway but then you need full coverage. I.E each panel needs an optimizer. The dual ones should have worked fine for you.

They are only dc-dc converters that match the voltage and impedance so that it can pass the feed current.

slave1

championc wrote: »

Even if only a QUARTER of ONE panel was shaded, it pulls EVERY panels' output down to the output of that panel.

So the option is for an Optimizer to be fitted to EACH affected panel, or remove them from the string and put on a separate Micro-Inverter

EDIT: posted as a heads up for those unaware of the effect of shading, and the potential solutions

Yep, totally known by me at install but I choose to go without optimisers and see how I get on given the number of panels I have and cost.
Now at least I know it’s a worthwhile investment, didn’t know about the monitoring piece though, would appreciate further advice/links to how that works please

idc

phester28 wrote: »

yes i have solis inverter and reporting is on an aggregated basis. You have to manually extract data for each string. as for the optimizers I think you need to buy the gateway but then you need full coverage. I.E each panel needs an optimizer. The dual ones should have worked fine for you.

They are only dc-dc converters that match the voltage and impedance so that it can pass the feed current.

For optimisers I think it depends on the model if it includes monitoring capability or not, could be wrong though. My installer figured the problem with the dual optimiser meant that if one panel was shaded the dual optimiser would take both down. Ie instead of 1 panel getting bypassed 2 did. If 3 or 4 of panels had shade that pretty much knocked off the whole array.
Would love to hear from someone on a single string results of before and after using optimisers and how much difference it made.

championc

idc wrote: »

For optimisers I think it depends on the model if it includes monitoring capability or not, could be wrong though. My installer figured the problem with the dual optimiser meant that if one panel was shaded the dual optimiser would take both down. Ie instead of 1 panel getting bypassed 2 did. If 3 or 4 of panels had shade that pretty much knocked off the whole array.
Would love to hear from someone on a single string results of before and after using optimisers and how much difference it made.

I have a single string with 12 panels, and I have optimizers on 5 of them.

Watts = Volts x Amps

What the optimizers do is reduce the voltage and increase the amperage. It means that the whole string overall voltage is lowered.

I've 3 on my shed roof which are totally shaded by the row of houses behind me, from early November until the middle of February. So my real output for December is more for just 2.7kWp

idc

championc wrote: »

I have a single string with 12 panels, and I have optimizers on 5 of them.

Watts = Volts x Amps

What the optimizers do is reduce the voltage and increase the amperage. It means that the whole string overall voltage is lowered.

I've 3 on my shed roof which are totally shaded by the row of houses behind me, from early November until the middle of February. So my real output for December is more for just 2.7kWp

Thanks for the info. I think i understand. Guess I'm trying to work out why the dual panel optimisers didn't work. If operating on two panels is similar to scenario with a single string on inverter with no optimisers (ie one panel shaded casues all panels to drop to same output as the shaded one)
In case of dual panels if it was the case each pair had one shaded panel then could that mean the optimiser is working like a normal string ie power of 2 panels drops to that of the shaded panel. Thus optimisers were working but as pretty much all pairs had one shaded panel overall power dropped and it would be better for me to get single panel optimisers??
(Been a long time since I did any electrical/circuit type work so only getting my head around parallel/serial circuits - any searches on web havnt really explained clearly how optimisers work. Some sites talk about the diodes internally in the panels so assumed optimisers worked similarly but on a whole panel basis. Ie panel shaded just skip it altogether!!!)

championc

Optimizers turn each solar panel into it's own individual MPPT unit

From Wikipedia

In order to optimize collection, modern solar arrays use a technique known as "maximum power point tracking" (MPPT) to monitor the total output of the array and continually adjust the presented load to keep the system operation at its peak efficiency point.

Traditionally, solar panels produce voltages around 30 V. This is too low to be effectively converted into AC to feed to the power grid. To address this, panels are strung together in series to increase the voltage to something more appropriate for the inverter being used, typically about 600 V.

The drawback to this approach is that MPPT system can only be applied to the array as a whole. Because the I-V curve is non-linear, a panel that is even slightly shadowed can have dramatically lower output, and greatly increase its internal resistance. As the panels are wired in series, this would cause the output of the entire string to be reduced due to the increased total resistance. This change in performance causes the MPPT system to change the operation point, moving the rest of the panels away from their best performance.

Because of their sequential wiring, power mismatch between PV modules within a string can lead to a drastic and disproportionate loss of power from the entire solar array, in some cases leading to complete system failure. Shading of as little as 9% of the entire surface array of a PV system can, in some circumstances, lead to a system-wide power loss of as much as 54%. Although this problem is most notable with "large" events like a passing shadow, even the tiniest differences in panel performance, due to dirt, differential aging or tiny differences during manufacturing, can result in the array as a whole operating away from its best MPPT point. "Panel matching" is an important part of solar array design.

idc

Yeah i think that explains why dual panel optimiser doesn't work either. when my array has 1 out of every pair of panels shaded. they all operate at the reduced output from those shaded panels. I plan to look into sorting out optimisers for every panel on my roof with shading.
And i will likely need it for every panel as way shade moves during the day/time of year pretty much every panel experiences continuous shade at different times.

DrPhilG

How expensive are optimisers and how much of an impact would they make?

Never noticed before, but at this time of the year my garage suffers shade from the house.



As you can see there's strong sunlight, yet I'm only generating 250-400w.

Once the sun gets over the top I'd be looking at 2-3 times that with this bright day although obviously the house panels will also be coming into action then.

But as its only an issue until about midday and only for a few months of the year, its hardly worth looking at optimisers is it?

Geeyfds53573

DrPhilG wrote: »

How expensive are optimisers and how much of an impact would they make?

Never noticed before, but at this time of the year my garage suffers shade from the house.



As you can see there's strong sunlight, yet I'm only generating 250-400w.

Once the sun gets over the top I'd be looking at 2-3 times that with this bright day although obviously the house panels will also be coming into action then.

But as its only an issue until about midday and only for a few months of the year, its hardly worth looking at optimisers

Buy 3 for €150 and fit yourself
It looks like it would be worth it

DrPhilG

3 optimisers? There's 9 panels. That view was later on in the shaded time. But an hour earlier and probably 7 were shaded.

PS now generating 1.7kW

Geeyfds53573

DrPhilG wrote: »

3 optimisers? There's 9 panels. That view was later on in the shaded time. But an hour earlier and probably 7 were shaded.

Oh damn at €50 a piece + install that’s a tough call to make

Geeyfds53573

DrPhilG wrote: »

3 optimisers? There's 9 panels. That view was later on in the shaded time. But an hour earlier and probably 7 were shaded.

PS now generating 1.7kW

So simple math if losing ~1 kW for ~4 hrs for ~4 months then ~500 kW maybe pays for 1 of them so 9 years

championc

Exactly what I have been talking about and you verified this 100%. So your output would have suddenly shot up once the last bit of shade left the bottom right corner.

You are losing very little. Solar noon is around 12:30, so look at your generation from 13:00 to 16:00. This will confirm your potential output from 09:00 to 12:00.

The sun is so low at this time of year, you'll get fook all before 10:30 anyway. And that's on the basis of a sunny day - which could be one cloudless day per month.

Look at what time the shade leaves the second last panel and the last panel. Then decide whether to buy one or two optimizers. I would certainly think about buying them for the last two, but that's about it really.

You'd be much better moving the up higher

Geeyfds53573 wrote: »

So simple math if losing ~1 kW for ~4 hrs for ~4 months then ~500 kW maybe pays for 1 of them so 9 years

No it's not as simple as that. You wouldn't be generating anything near even 500w at 09:00

DrPhilG

championc wrote: »

Look at what time the shade leaves the second last panel and the last panel.

You'd be much better moving them up higher

How difficult is it to fit optimisers? I'm not a complete technophobe but I'm also happy to pay a few quid for a pro to do it right.

Aa for moving them, I probably will in the next year or 2. Hoping to double both house and battery panels then, pending (hopefully) a review on this 50cm nonsense from the council.

I might get the installer to add optimisers on the outer panels then. Closer to the time I'll shift one of the cctv cameras to capture it for easy analysis of the times and shading.

Currently I get this, a little nudge up and it'll give me the full picture re shading.

championc

DrPhilG wrote: »

How difficult is it to fit optimisers? I'm not a complete technophobe but I'm also happy to pay a few quid for a pro to do it right.

Aa for moving them, I probably will in the next year or 2. Hoping to double both house and battery panels then, pending (hopefully) a review on this 50cm nonsense from the council.

I might get the installer to add optimisers on the outer panels then.

You could chop the peak off the house roof

Just move the panels up (by 2 tiles). You're breaking more of a law with over 12m2 than you would be with a few cm from the top ridge. And who can see them anyway, and you've got your grant, so away you go now.

Tigo optimizers are built with clips, which allow them to slide straight into the corner on the underside of any panel. You don't even have to remove the panels at all. You just connect the panel cables to the Tigo and then connect the Tigo to the string. 5 mins tops.

DrPhilG

championc wrote: »

You're breaking more of a law with over 12m2 than you would be with a few cm from the top ridge.

Difference is that if I apply for planning with the current layout I meet the criteria for approval. If I go inside the 50cm limit then I won't.

championc

DrPhilG wrote: »

Difference is that if I apply for planning with the current layout I meet the criteria for approval. If I go inside the 50cm limit then I won't.

I still cannot understand why you are giving any thoughts whatsoever to "planning". By all accounts, you appear to be in the a******e of nowhere, and any complaint would only likely come from overlooking neighbours.

Would they need binoculars or a telescope ?

DrPhilG

championc wrote: »

I still cannot understand why you are giving any thoughts whatsoever to "planning".

Long story, but I know some folk in the council. And I wouldn't put it past them to squeal.

Bobeagleburger

The planning laws will surely change. They are reviewing them soon if they haven't already. I had a link to a questionnaire a month ago sent from a green party rep.

Contact your local TD to keep the pressure on. CC any green TDs on it too. No harm.

A woman in Clare with too many panels (by current law) had her case thrown out so the precedent is there.

DrPhilG

6 wrote: »

The planning laws will surely change. They are reviewing them soon if they haven't already. I had a link to a questionnaire a month ago sent from a green party rep.

Contact your local TD to keep the pressure on. CC any green TDs on it too. No harm.

The Minister for Agriculture is a close neighbour too. Must have a whinge in his ear.

DrPhilG

For those with Energia, when do they allow a meter reading?

My bill is due on the 8th and still no option to submit.

garbeth

DrPhilG wrote: »

For those with Energia, when do they allow a meter reading?

My bill is due on the 8th and still no option to submit.

I’m with energia as well. Last meter reading was open on the 25-29th of November. My bill was due 11th of December

championc

DrPhilG wrote: »

Long story, but I know some folk in the council. And I wouldn't put it past them to squeal.

Just join FF or have a supply of brown envelopes

MAULBROOK

DrPhilG wrote: »

3 optimisers? There's 9 panels. That view was later on in the shaded time. But an hour earlier and probably 7 were shaded.

PS now generating 1.7kW

To be honest you have given your supplier so much work with recommendations, they should give you them for free and thank you for it.

E30M3

championc wrote: »

My new LiFePO4's

That looks very interesting ChampionC and I think many of us would be grateful if you would consider starting a new thread re your install and what you have learned. I know you are generally very generous with your time and sharing your experiences on the various threads.

For my own part I'd be wondering about a BMS and if you have one and if so what has been your experience?

Charge/Discharge rates?

What Inverter you are using?

Extras you purchased Connections? Cables Brackets? Etc.

Lead time for Delivery?

Could it be doubled with another pack?

Personally I have a 5Kwh Solis Inverter and 2 2.4 Pylontech Batteries. I'd consider either purchasing 2 more Pylontech 2nd hand to get to 9.6 if I got them 2nd hand at a viable price or selling my current and replacing with a setup similar to your own.

Installed since August and would wait a full year before deciding but currently my experience would be that Both Batteries and Water Diverter are redundant on my setup from End September but others may of course have a different experience depending on Orientation, I'm East/West

graememk

E30M3 wrote: »

That looks very interesting ChampionC and I think many of us would be grateful if you would consider starting a new thread re your install and what you have learned. I know you are generally very generous with your time and sharing your experiences on the various threads.

For my own part I'd be wondering about a BMS and if you have one and if so what has been your experience?

Charge/Discharge rates?

What Inverter you are using?

Extras you purchased Connections? Cables Brackets? Etc.

Lead time for Delivery?

Could it be doubled with another pack?

Personally I have a 5Kwh Solis Inverter and 2 2.4 Pylontech Batteries. I'd consider either purchasing 2 more Pylontech 2nd hand to get to 9.6 if I got them 2nd hand at a viable price or selling my current and replacing with a setup similar to your own.

Installed since August and would wait a full year before deciding but currently my experience would be that Both Batteries and Water Diverter are redundant on my setup from End September but others may of course have a different experience depending on Orientation, I'm East/West

I have a similar setup now, Using a Sofar ME3000sp - a dedicated storage inverter

Batteries took about 2 months to arrive. They are a lot more "hands on" than pylontech where they are just plug in and go.

The ME3000sp handles the charging and discharging of the pack, and Im still currently waiting on a passive balancer.. Fried my first one because i wired it up wrong! - always double check the voltages before plugging in!.

Running without the balancer at the minute but keeping a close watch on the voltages of the cells, and they are all staying in balance. - I am the BMS

Using the "DEFAULT" profile so all voltages have to be set manually and it seems to assume a fairly straight discharge, (Lifepo4 discharge/charge is very flat with flicks at each end)

Lots of tweaking settings but i think im 95% of the way there now.

I got them as a project - not to save money.. (i think charging on nightrate has a payback of 50-70c/day). accounting for charging/discharging losses (about 15%).