OT - Renewable stuff for sale and wanted

System

This discussion was created from comments split from: Renewable stuff for sale and wanted.

unkel

Are you sure @Buffman? These things are very unreliable. I wouldn't want to stick them anywhere where they are not easy to get at and replace.

bullit_dodger

https://www.boards.ie/discussion/comment/121142620#Comment_121142620

I've no love of optimizers, I think people overuse them on installs thinking they need them when infact they don't, but do you have data as to the unreliability unkel? I ask as I'm interested in if you had a proven failure rate as opposed to "gut feeling".

Tigo Optimisers Review - ESE Group LTD

and to be unbiased.

Tigo Optimiser Recall? – MC Electrical

That said, they fail "on", meaning if one was to fail, then the panel would produce the same output should an optimizer not be present. Which is pretty much zero risk, other than being out of pocket. Failure rate is 0.2%, so 1 in 500 will fail after warranty (25 years). That's pretty low and probably similar to an actual solar panel failure rate.

My main issue I have with them is that they are sort of branded as "optimizers" in such a way that it infers that they'll somehow improve a solar install (even ones which have no shading). It's misleading advertisment by a lot of installers.

unkel

Yeah nice figures on paper, I'm aware of them. And great that they are supposed to fail "on" but obviously they don't always do. Personally I wouldn't touch them unless I had to. Like in having a very, very limited space for PV panels with a lot of shading. And even if that was the case, I'd probably just live with the shading, or not have PV panels (there) at all and maybe instead go with a battery only system, this is very profitable these days

I know of at least 2 regulars in here who've had problems with tigo optimizers. I had one myself, just to play with it and found it a load of meh. As you say, they don't of course do any optimising at all. And cost about half the size of a panel. Better off to just have another few panels (that get shaded) rather than optimizers. And if it really is a poor setup, use micro inverters, instead of optimizers, with the same result. Although these of course fail too. All electronics fail.

championc

I had two or three which failed. I stupidly got them for the last evening hours, but in reality, the sun was so low anyway that the losses were negligable.

And I can absolutely say 100% that they did NOT fail open in the sense of producing current.

What they actually did was removed the panel from the string as though it didn't exist, rather than breaking the string.

So again, maybe a bit ambiguous with the wording, but failing open appears that it's just a passthru for voltage and current to the next panel in the string

allinthehead

https://www.boards.ie/discussion/comment/121143306#Comment_121143306

You could actually set the system up so the microinverters are in the attic so replacing them would be very straightforward should it be required. 4 port microinverters make for a very simple system. Apologies for the digression.

10-10-20

https://www.boards.ie/discussion/comment/121143473#Comment_121143473

That's my plan for my microinverters. Bring all of the DC cables in through the fabric and attach them in the attic space, and run the AC internally too. (but don't tell championc, he's not a fan of microinverters 😉 ).

allinthehead

https://www.boards.ie/discussion/comment/121143768#Comment_121143768

Good plan. I have 3 different angles on my panels SE, NW and W so micro's made sense for me. All accessible from the ground.

unkel

My biggest beef with micro inverters (never mind optimizers) is that the more of them you use, the bigger the chance one will break, going so far that if you have 20 of them, quite likely every year one will break. Now this is of course not so much an issue at all if the inverters are in the house and easily accessible, like you guys are doing / planning

But in practice, most are installed on the high roof. And I ain't going up there 😁

championc

I'm not a fan when an €80 GoodWe that also has built-in WiFi can do the same job as spending a few 100's .

But if working with less than 4 panels, it's a perfect solution.

It's Optimizers that I have zero enthusiasm for

allinthehead

https://www.boards.ie/discussion/comment/121144134#Comment_121144134

Agreed, the less complication on a high roof the better.

plasterman

https://midsummer.ie/buy/AC-and-DC-isolators/imo-4pole-40a-dc

Basic question, is the rated voltage for DC isolating switches like the on here given in series for 4 pole / 2 string? Ie here is the maximum total voltage for 2 strings in series 600V? No datasheet available.

championc

https://www.boards.ie/discussion/comment/121159874#Comment_121159874

I have two north facing strings - identical - one gets chimney shaded in mornings.

But feck all difference overall

unkel

https://www.boards.ie/discussion/comment/121162954#Comment_121162954

Haha, exact same experience here. Got it cheap, played with it, didn't do much, sold it on. That was many years ago.

bullit_dodger

https://www.boards.ie/discussion/comment/121162954#Comment_121162954

Again, I'm not a fan of optimizers, but I think people are perhaps being overtly negative here. They have their uses, specifically on an array which might have two or more orientations on panels. I'd be slow to adopt them and would look for alternatives myself. That said, right tool for the right job in some scenarios. Your mileage will vary, etc.

unkel

https://www.boards.ie/discussion/comment/121163120#Comment_121163120

When two or more orientations and you don't have enough panels in a string or inputs on a string inverter, you should use micro inverters, not optimizers.

DC999

https://www.boards.ie/discussion/comment/121163120#Comment_121163120

Agree, they have a place. They work for me on 5 of 16 panels and I’m more than happy with them. They are only on an East flat-roof that gets shade every morning and evening as the sun rises and moves around. Plus there’s a lot of autumn, winter and spring shade from tall trees that they help with (casting shade on only some of the 5 panels).

Pic shows the side of our house casting a shadow on the flat roof (pre panels going in) later in the day. That's the only place we have them. The main roof above it won’t have that shadow of course as there is no wall to block it. In the morning you’ll see the shade kinda the opposite (from right to left, not left to right - but less obvious).

We also reduced the height of vent pipes that would have shaded 2 orientations (you can see one in the pic that has since been lowered). So where possible, go old-skool and remove shade too. 

If they fail, well it's a flat roof with access out the window or from the ground on a ladder. They have something like a 20 year warranty - so I'm assuming the company have confidence they will last. And I'll cross that bridge if / when they fail. The inverter will likely fail well before them.

unkel

@DC999 - the vulnerability is in the numbers. If you have just one, chances are it will outlast your inverter. But if you have 10-15 of them then 1 of them failing every year is par for the course. I'd rather a system on my roof where there is near zero chance of anything failing (as in, just panels)

graememk

https://www.boards.ie/discussion/comment/121163574#Comment_121163574

or they all will last for 5+ years and then start dropping like flies!

On another note, I should have an me3000 for sale soon, putting the word out here before going the adverts route (also getting dpd to collect+deliver is super easy, No travel to the wilds of donegal needed!)

unkel

https://www.boards.ie/discussion/comment/121163663#Comment_121163663

Asking price would help there or you will have people wasting your time and you wasting their time 😂

For the folks not aware, the ME3000SP is about the cheapest option out there to have an AC side "power wall" system, you don't even need to have any solar PV, just hooke it up to a battery. This system is now more relevant than ever as you can charge your battery from the cheap night rate and dump into the grid when you get paid well for it (or use it yourself during peak times)

bullit_dodger

https://www.boards.ie/discussion/comment/121163574#Comment_121163574

We've talked about this before .... the probability math doesn't work like that. For sure, if you have more devices your chance in getting a failure goes up - but if the failure rate is 1 in 500 for a device and let's say you have 10 units, it doesn't mean that it goes to 1 in 50. It's actually fairly complicated how it's worked out, depends on the failure distribution curves etc. There's a whole branch of probability on it.

Failure rate - Wikipedia.

For optimizers they'll have some failure distribution curve, could have a spike at the start, a long low plateau and then rises as weather and age gets to them. Or you tend to get batches (let's call them "monday morning batch") which have higher failure rates, and other batches low. So you could get lucky/unlucky.

To be clear, I'm not making a case for "ohh use optimizers, they are 100% reliable" - I'm not. I'm just saying that there is a time and a place for them. Me? I've micro-inverters and they can fail too. Am I worried, nahh - they'll be fine. You start worrying about electronic and you'd never buy a toaster :-)

Edit: I do think though that some of the claims that Tigo etc have made are ..... dubious.

unkel

Yeah I know about statistics and MTBF and normal distribution, but you are comparing the like of inverters with the like of hard disks that maybe have a failure rate of 1 in 500

Most inverters will be dead within 10 years, I do realise that if you have 10 of them, they won't neatly die on the first of January every year for the next 10 years, more likely none will die in the first 4-5 years, then most will die between 8-12 years and the last few will all be dead by 18-20 years

You seem to be missing my point is that if you have loads of electronic components on your roof, chances are you have to go up there regularly to replace broken ones. My aim is to NEVER GO BACK ON THE ROOF AGAIN, EVER! So no electronics there for me. You understand me now? 😂

bullit_dodger

Well the 1 in 500 was from the link I posted earlier. I don't have any other data - but happy to know if some is data out there which has found otherwise/contradict that. Tigo Optimisers Review - ESE Group LTD

Specifically "Tigo claims that its optimisers are so reliable that only 0.2% are returned as defective". So the 0.2% work out as the 1 in 500 I mentioned. granted that's Tigo talking about their own stuff - so there's no bias there - Right?! LOL

While we're at it, it's worth also talking about failure rates of other things like string inverters.

Survey shows 34.3% failure rate for residential inverters over 15 years – pv magazine International (pv-magazine.com)

pv-magazine I think are fairly decent/reliable.....and it actually surprised me that it would be so high if I'm honest. I mean sure, like all things electrical I'd expect failures, but that seems high to me. I'd have guesses 15%-20% myself. I do respect that argument about not letting them near your installations though. I've no love of them either, but I think your missing the point that there's a time and a place for things.

Might be going on a tangent of the "Renewable stuff for sale" :-)

unkel

I trust my own experience and that of others on here over a manufacturer's claims, don't you? 😂 You must have missed @championc post that several Tigo optimizers failed (closed!!!) on him in a short period of time - so back on the roof

And my own record of string inverters is far worse than your figures too (not better like you were expecting). But that is not a problem. I sell the broken ones for a few bob for parts or repair, get brand new replacement ones for free under warranty and replace them myself. Not on the roof.

bullit_dodger

If I buy a Sony TV and it goes BANG(tm) does that mean all Sony TV's are bad? No, course not. I just got unlucky.

I get it what your saying and fully agree with parts of the argument by the way. That said, DC999 has been using them successfully (above) too for a few years and he's had no issues. That wouldn't make them "good" in my eyes either, just that I wouldn't infer anything from small sample sizes. That's why I always look for large data sets ideally. In the absence of that, sure makes sense to fall back on your own experiences.

I guess we'll have to agree to disagree.

unkel

I don't want to ever go back on the roof or having to pay anyone to do it for me, and you don't seem to mind this or take your chances with it because the manufacturer says the chance is slim. That's the only thing we seem to disagree on 😂

con747

https://www.boards.ie/discussion/comment/121166326#Comment_121166326

I know you're very knowledgeable in this area but by you're logic if 10 houses on the same street buy a tv or washing machine or any appliance 1 appliance is going to fail every single year for 10 years in one of the houses. I just can't get my head around that!

championc

The main point is being missed here. In most cases, bypass diodes would appear to remove the need for optimizers.

It's impossible to say that they work if they are in a string. If you had a graph from before and after adding them, then that would be a must for a proper comparison.

What I can say is that I have two rows of north facing panels in portrait. The upper string gets shaded by a chimney, covering 1.5 panels in early morning. Yes, maybe a whole kWh of a different in total across a day. It certainly does not wipe out generation

SD_DRACULA

https://www.boards.ie/discussion/comment/121167249#Comment_121167249

I also have 4 optimizers on my roof due some morning chimney shading but hard to know if needed or not unless testing with and without

I did a test a while back on the 12 panel string on my shed, I covered one panel completely and even two and production did not go to 0 so that much might not need optimizers.

However that same string gradually gets shaded by the house fully in about two weeks from now and once half the panels get shaded the output is being destroyed even for the 6 unshaded.

I think people are best testing without first then if the output is minimal then maybe they are needed.

rosmoke

I've a string with 3 Jinko 470w each, on a south facing extention at a very low angle (pointing upwards towards south-east) have heavy shading on last panel due to trees and on 22nd of Sept added a Tigo optimiser just for the craic to see if it would help. So these panels are faced literally towards the sun in the morning so should produce a bit more. On the other side of the extension I have 5 panels pointed towards west and production is way better just before sunset.

Here are some pictures and stats from home assistant for this particular string, bear in mind sun was going strong on the other 2 panels, especially in the morning 9-10:30am and they are still producing peanuts .. they'll probably produce more if I disconnect the last one (that'll be a nice test)

22nd was very similar in terms of overall production to 21st for my particular array system (7.4kw split across everywhere except north). Overall production was 20.4kWh on 21st and 21.2kWh on 22nd.

Mornings 9-12 are the most relevant as last panel has shading until 10:40am.

I don't see any big difference, I know it's not a lot of data to go by but I looked at other days and it's similar.